When does soreness after the gym mean a trip to A&E? Rhabdomyolysis, overtraining, and what normal urine colour cannot rule out

TL;DR The biggest myth: "I looked at my urine, the colour is normal, so I must be fine." That inference runs backwards. Tietze and Borchers (Sports Health 2014) state that rapid clearance of myoglobin from the urine makes it a less sensitive indicator and that it should not be used as the sole objective diagnostic marker [Note 1]; StatPearls (updated 7 July 2025) measured dark urine in about 30% to 40% of patients (another section of the same page says about 50% — both figures are reported here), and the full triad of muscle pain, weakness and tea-coloured urine in fewer than half [Note 2]. Rawson et al. (2017) record ultra-marathon runners with myoglobinuria but without rhabdomyolysis, and an eccentric exercise experiment in which creatine kinase was extremely high yet no participant had visible myoglobinuria [Note 3]. Normal urine colour rules nothing out, and dark urine is not a diagnosis either. The second myth: "I just overdid it, a rest will fix it." This is the conclusion a reader is least entitled to reach alone. Kreher and Schwartz (Sports Health 2012) state that if an athlete presents with underperformance without a period of rest, overtraining syndrome cannot be diagnosed, and that the diagnosis can be made only in retrospect [Note 4]; the joint consensus statement of the European College of Sport Science and the American College of Sports Medicine of 2013 states of the existing markers of overtraining that none of them meets all the criteria to make its use generally accepted [Note 5]. In the study that document cites (Reid et al., Br J Sports Med 2004, 41 competitive athletes with persistent fatigue and/or recurrent infections associated with performance decrements), a cause was identified in 68% — and that study published what the causes were: most commonly partial humoral immune deficiency 28%, unresolved viral infections 27% and non-fasting hypoglycaemia 28%, with allergic disease 15%, new or poorly controlled asthma 13%, sleep disorders 15%, upper airway dysfunction 5%, iron depletion 3%, and one case of a thyroid disorder. And the same document carries a list of organic diseases to be excluded one by one, including thyroid disease, iron deficiency (with or without anaemia), myocarditis and hepatitis. Hong Kong has a real figure for gym injuries. The Centre for Health Protection's Report of Unintentional Injury Survey 2018 (PDF file's own revision date 2 September 2021; fieldwork 17 September 2018 to 14 July 2019): against a population of 7.22 million in the first quarter of 2019, 0.8% of people had a sports-injury-related injury event in the 12 months before the survey; of 326,100 injury events across Hong Kong, 17.5% (57,000) were sports-related; of those, "fitness training" accounted for 4.1% (2,300 events), with seven rows above it in the same table, six of them named sports (basketball, football, jogging, cycling, hiking, badminton) and the seventh a residual category of other sports; and the leading direct mechanism was overexertion, at 51.8%. The route to care and the charges are published: the Hospital Authority's accident and emergency departments at 18 public hospitals, with five triage categories; 400 dollars per attendance for eligible persons, with those triaged as Category I (critical) and Category II (emergency) exempted; and if you leave after triage without seeing a doctor, 350 dollars may be reclaimed within 24 hours. This article will not teach you to judge for yourself whether it is rhabdomyolysis, will not teach you to treat heat stroke or rhabdomyolysis yourself, and prescribes no training or supplement dose. Those are for a doctor. It sets out only sourced facts and the officially published levels of help.

#How many people in Hong Kong are injured playing sport or training?

Hong Kong has a government-measured figure for sports injuries, and "fitness training" is only 4.1% of it; and not one of the sources cited here carries a Hong Kong figure for rhabdomyolysis.

The Centre for Health Protection's Report of Unintentional Injury Survey 2018 (the Injury Survey) is the only government survey of sports injuries in Hong Kong found for this article. It defines a sports injury first: a sports-injury-related injury event means the injured person was hurt while engaged in a sports-related activity (for example competing, taking part in sport recreationally, or warming up) [Note 6].

Which is to say: even a warm-up injury counts. The report's own figures follow.

"Overexertion" is an injury coding category, not rhabdomyolysis. The report's own footnote states that under ICECI, overexertion means a load that causes discomfort or injury to the body, divided into acute and non-acute; acute overexertion occurs over a short and sudden course, an example being spraining an ankle while lifting something heavy; non-acute overexertion is caused by the cumulative effect of repeated activity, with gradual and/or delayed onset, an example being joint strain from marathon running or rowing [Note 6].

In one sentence: its own examples are a sprained ankle and joint strain. It is not, and does not claim to be, a figure for rhabdomyolysis, and this article will not use it as one.

Do the arithmetic (straight from the figures in the table above): 57,000 sports injury events × 4.1% = 2,337 events, which is the 2.3, in thousands, that the report prints; spread across the year, about 195 a month. Basketball over the same period is 22.9%, about 13,053 events, or 5.6 times as many as fitness training. So neither "the gym is dangerous" nor "the gym is where most injuries happen" holds up: of the rows listed in table 3.13, seven have a larger share than fitness training — six named sports plus a residual category of other sports; fitness training is about one twenty-fourth of all sports injury events.

At the same time, Hong Kong's own official exercise advice includes resistance training. The Centre for Health Protection's Physical Activity page (page's own date 15 April 2025) quotes the World Health Organization: adults should also do muscle-strengthening activities at moderate or greater intensity targeting all major muscle groups on two days or more each week [Note 7]. The same page quotes the Behavioural Risk Factor Survey of 2023: 14.8% of people aged 18 and above are insufficiently physically active, 16.0% among women and 13.4% among men. Do the arithmetic: 100% − 14.8% = 85.2% of people aged 18 and above meet the physical activity target.

So this article is not telling anyone not to train — the recommendation the Centre for Health Protection quotes tells people to train on two days a week or more. What this article is about is how to start and when to stop.

⚠️ If the news makes it feel as though a lot goes wrong in gyms and you are wary of going: the figure the Hong Kong Government measured is 4.1% — seven rows in that table have a larger share (six named sports, plus a residual category of other sports).

#What is rhabdomyolysis, and how does "training till you cramp" reach kidney failure?

Once muscle cells rupture, the proteins inside them enter the blood; and when myoglobin among them reaches the kidneys, it can cause acute kidney injury.

The mechanism first. Creatine kinase (CK; some of the literature writes creatine phosphokinase, CPK) is an enzyme inside muscle cells that leaks into the blood when muscle is damaged, and is the laboratory's marker of muscle damage. Myoglobin is the oxygen-carrying protein in muscle; it too leaks into the blood, and is then cleared by the kidneys — and that is the step where the problem lies.

Rawson et al. (Sports Med 2017) state that reduced hydration impairs the kidneys' ability to clear myoglobin and other potentially myotoxic substances, thereby increasing the risk of myoglobin precipitation, renal cast formation and possibly factors local to the kidney such as oxidative stress, raising the risk of renal failure; and that although dehydration is a risk factor, it does not have to be present for clinically relevant rhabdomyolysis to manifest [Note 8].

Which is to say: dehydration makes it worse, but it happens without dehydration too.

Why the gym in particular? Because of eccentric contractions. The same paper states that the contractions causing the most muscle damage are those in which the muscle lengthens as it is attempting to contract (referred to as eccentric in the classical literature), for example lowering the weight during a biceps curl, which the gym calls "negatives"; high-force lengthening contractions place strain on the muscle fibres, damage protein structure, and release muscle proteins into the circulation [Note 8].

#Which situations carry more risk (the source's own list, not exhaustive)

The risk factors Rawson et al. (2017) list for exertional rhabdomyolysis are: an increase in exercise intensity or duration or the use of different muscle groups (unaccustomed strenuous exercise); contraction type (eccentric or lengthening more than concentric); infection; medication use; dietary factors such as hydration; environmental factors (extremes of heat and cold); sex (males more than females); and genetic factors [Note 9].

That list is open-ended — the source's own words are "can include" and "including". Not being on the list does not mean no risk.

Three points deserve singling out, because popular versions regularly leave them out or get them wrong:

• On medication, what is sourced is statins, non-steroidal anti-inflammatory drugs and ephedrine. Rawson et al. note that as many as 5% of statin users have muscle pain, and that about 0.1% of all users will experience rhabdomyolysis, defined as a CK elevation to more than 10 times the upper limit of normal [Note 9]. StatPearls writes that statins are the most common pharmaceuticals to cause rhabdomyolysis, with up to 10% of patients taking them experiencing muscle pain [Note 2]. On NSAIDs, Rawson et al. write that painkillers can reduce renal perfusion, leading to a depressed glomerular filtration rate [Note 9]. On the widely repeated claim about excess caffeine: none of the three documents above (Rawson et al. 2017, StatPearls, Tietze and Borchers 2014) mentions caffeine anywhere in its risk factor or medication passages, and this article therefore makes no statement about it.
• Genetic factors hold up, but they are not the explanation for a first episode. Rawson et al. note that inherited conditions such as metabolic myopathies are not typically associated with the first bout of exertional rhabdomyolysis after strenuous unaccustomed exercise [Note 9].
• Spin classes have two case series behind them, but no source calls them "the most common cause". Yow et al. (Cureus 2021) record an increased occurrence of spin-related rhabdomyolysis among previously fit adults after their first spin bike class, presenting with the triad of myalgia, muscle weakness and dark tea-coloured urine within a week of that first session [Note 10]. The three cases in Ramme et al. (2016) occurred in deconditioned individuals. The phenomenon is sourced; the ranking "one of the most common causes" is not, and only the former is written here.

#How common is it, and what happens afterwards?

All of this has to be read with its denominator:

• Tietze and Borchers (2014): the incidence of exertional rhabdomyolysis is approximately 29.9 per 100,000 patient years.
• Rawson et al., citing a report on military recruits: 22.2 cases per 100,000 military trainees per year.
• The same paper is blunt about why only a few people are affected: only a small percentage of individuals exposed to the same exercise conditions experience rhabdomyolysis [Note 11]. One case from a secondary school physical education lesson: 119 students aged 17–18 did 120 press-ups in 5 minutes, and post-exercise serum CK ranged from 55 to 174,260 U/l, with 20 students requiring admission. Another: a 12-year-old boy made to do 250 to 500 squat jumps as a punishment, whose CK rose from 92,115 U/l to 244,006 U/l on day 4, with 7 days in hospital — while none of his classmates was admitted.
• On marathons: of 25 runners, 40% showed evidence of acute kidney injury immediately after the race, which resolved within the following 24 hours; and over the 18 years from 1969 to 1986 of South Africa's Comrades Marathon, with 2,000 to 10,000 entrants a year, only 19 cases of acute renal failure were reported [Note 11].

Complications (reproduced in full from StatPearls, whose own word is "include", so not exhaustive): acute kidney injury, electrolyte abnormalities, arrhythmia, compartment syndrome, disseminated intravascular coagulation, end-stage renal disease requiring renal replacement therapy, and infection from prolonged hospitalisation.

The mortality figure has to be read with its denominator. StatPearls writes that for hospitalised individuals who develop acute kidney injury in the setting of rhabdomyolysis, the mortality rate is 30% to 50% [Note 2]. That denominator is patients already admitted and already in acute kidney injury; it is not the risk faced by someone who goes to the gym. The same page also writes that if identified early, the prognosis of acute kidney injury from rhabdomyolysis is relatively benign [Note 2]. The two sentences have to be read together.

⚠️ If you are about to do your first spin class, your first heavy eccentric work, or to chase lost ground after a few months off: what all three documents have in common is "unaccustomed strenuous exercise" — the weight is on "unaccustomed", not on "long-trained".

#Why is "I'm just overtrained" the conclusion you are least entitled to reach?

Because overtraining syndrome (OTS) can by definition be confirmed only looking back after a rest, and in athletes whose performance has dropped, the most common outcome is that another illness is found.

The three-tier terminology first, because popular accounts run it all together. Kreher and Schwartz (Sports Health 2012) set out the European College of Sport Science definitions in a table:

What separates the three tiers is not the symptoms but how long a rest it takes to come back. The same paper states that differentiating non-functional overreaching from overtraining syndrome is clinically difficult and can often be made only after a period of complete rest, and that the difference between the two is based on time to recovery and not necessarily on the degree or type of symptoms [Note 4].

And the two decisive sentences: if an athlete presents with underperformance without a period of rest and recovery, overtraining syndrome cannot be diagnosed; and given the definitions of the two, the diagnosis from history can be made only in retrospect [Note 4].

#And in people whose performance has dropped, another cause is found in 68%

Kreher and Schwartz write that in one of the few studies describing the evaluation of underperforming athletes, a cause for repeated infections and/or fatigue was found in 68% of regional-level or higher athletes, and that 93% of the athletes reported decreases in performance [Note 12].

The two sentences that follow have to be carried with it, because they qualify how that 68% was arrived at. The same paper states that this evaluation was significant for a more extensive and costly laboratory evaluation, including vitamin B12, folate, serology for viral hepatitis, toxoplasmosis, cytomegalovirus and Epstein-Barr virus titres, Epstein-Barr virus DNA in saliva, serum and salivary immunoglobulins, and antinuclear antibodies; and that such extensive testing should be considered only in the appropriate setting [Note 12].

That last sentence is the boundary of the whole passage: the source says itself that this battery is not for everyone.

Which is to say: the 68% is not "go to a doctor and 68% get an answer", it is "after that whole battery of tests, 68% got an answer". How much and which tests is for a doctor to decide by the circumstances — which is also why this article sets out no list of tests.

Which study that 68% comes from, its denominator, and what the causes were, are all public. The reference Kreher and Schwartz cite is Reid VL, Gleeson M, Williams N, Clancy RL, Br J Sports Med 2004;38(1):42-5 (PMID 14751944). That study took 41 competitive athletes (22 male, 19 female) with persistent fatigue and/or recurrent infections associated with performance decrements, who had a thorough medical examination and a series of clinical investigations; conditions with the potential to cause fatigue and/or recurrent infections were identified in 68% of them, the most common being partial humoral immune deficiency (28%) and unresolved viral infections (27%), with non-fasting hypoglycaemia also common (28%), and others including allergic disease (15%), new or poorly controlled asthma (13%), upper airway dysfunction (5%), sleep disorders (15%), iron depletion (3%) and one case of a thyroid disorder; a positive antinuclear antibody was detected in 21% of the athletes without clinical evidence of autoimmune disease, and evidence of Epstein-Barr virus reactivation in 22% of those tested [Note 13].

The denominator is 41 people, and 68% is about 28 of them. ⚠️ The percentages above are those printed in that study's abstract; nothing beyond the abstract is stated here. Two things to note: first, the entry condition for this group was "persistent fatigue and/or recurrent infections", not simply "performance has dropped" — the performance decrement is an associated feature (Kreher and Schwartz write that 93% reported decreases in performance); second, 41 is a very small sample.

And that study's own concluding sentence points exactly the same way as this section: athletes with recurrent infections, fatigue and associated poor performance may benefit from a thorough investigation of potentially reversible underlying medical conditions, especially when those conditions disrupt training and competition [Note 13].

Which is to say: the direction the source itself points is "go and get investigated", not "go and rest".

The same paper lists the organic diseases to be excluded, and states itself that the list is "not limited to the following": undiagnosed asthma or bronchial hyperreactivity, thyroid disease, adrenal disease, diabetes mellitus or insipidus, iron deficiency with or without anaemia, infection (myocarditis, hepatitis, HIV and so on), and malnutrition (from eating disorders, coeliac disease and so on) [Note 12].

This is the point. "Persistent fatigue, performance dropping, tired however much I sleep" — in that study of 41 people, 68% of this group had a cause found (immune, viral, hypoglycaemia, asthma, sleep, iron, thyroid), and Kreher and Schwartz's own exclusion list carries myocarditis, thyroid disease and iron deficiency. So "I am just overtrained, two weeks off will fix it" is a conclusion to be reached after a doctor has excluded other illnesses, not one for the reader to reach. This article therefore provides no self-check list of overtraining symptoms.

#Why this article provides no self-assessment checklist

Three sources in their own words:

• Kreher and Schwartz on the symptoms themselves: the symptoms of non-functional overreaching and overtraining syndrome are varied, non-specific, anecdotal and numerous [Note 14].
• The same paper on blood tests: there have been no specific or sensitive levels defined for creatine kinase, urea or iron [Note 14].
• The joint consensus statement of the European College of Sport Science and the American College of Sports Medicine of 2013 (Meeusen et al., Med Sci Sports Exerc 2013;45(1):186-205): several markers are currently used (hormones, performance tests, psychological tests, biochemical and immune markers), but none of them meets all the criteria to make its use generally accepted; and on whether OTS symptoms are more severe than those of NFO, there is no scientific evidence to either confirm or refute the suggestion [Note 5].

There is an assessment tool, but it is for clinical use. The International Olympic Committee's 2023 consensus statement on Relative Energy Deficiency in Sport (REDs) (Mountjoy et al., Br J Sports Med 2023;57(17):1073-1097) introduces a REDs Clinical Assessment Tool-Version 2, which the abstract itself describes as assisting in the detection and clinical diagnosis of REDs. This article notes only that the tool exists and that it is for clinicians; it will not reproduce it — a scoring sheet designed for a clinician who has already taken a history, examined the patient and run the tests becomes something else in the hands of someone at home deciding whether to see a doctor. For the same reason, this article does not reproduce table 2 of Kreher and Schwartz's symptom comparison either.

The core concept of REDs is worth knowing in itself: low energy availability, which the abstract defines as energy intake insufficient relative to exercise energy expenditure. That is, not eating enough to support how much you train — what people colloquially call eating too little and training too much.

On prevention, the source is candid: given the unethical nature of inducing overtraining syndrome in athletes and the uncertain pathogenesis, there are no evidence-based means of preventing it [Note 15].

⚠️ But that sentence cannot be where this stops, because the next word in the source is "However". The same passage continues: however, observation of training load, performance measures and mood questionnaires can help interrupt the progression from functional overreaching to non-functional overreaching or overtraining syndrome; one study showed a decrease in "burnout" in collegiate swimmers from 10% to zero when training load was altered in response to the Profile of Mood States questionnaire, with training load reduced when the mood state fell; the major components of prevention are screening and education; and athletes at risk of overtraining should be taught that one of the initial signs of overreaching is an increased rating of perceived exertion for a given workload [Note 15].

That last sentence is the one observation in the whole section that needs no measurement and no laboratory: the same weight, the same pace, and it feels harder. But it is a prompt, not a threshold — the source attaches no value to it, and neither will this article.

The two sentences have to be read together or the meaning inverts. What the source says is that there is no prevention method validated by randomised controlled trial, not that there is nothing to be done — its very next sentence lists what can be done: watch the training load, watch the performance, watch the mood, and cut the load when the mood falls. This is the one preventive practice among the sources cited here with a number behind it (10% to zero), and the only one that does not need a laboratory value the reader does not have. But remember the denominator: a squad of collegiate swimmers, implemented by a coaching team, not one person filling in a questionnaire at home.

The same paper writes that the management is rest, but that it is unclear which strategy is best — complete rest or relative rest is something the source leaves open. And the sentence immediately following is a direction: if stress, depression and/or anxiety are increased with full rest, relative rest with well-defined expectations should be provided [Note 15]. Which is to say: stopping entirely is not automatically the safer option, and the source leaves itself room on the point. That judgment too is a doctor's, not the reader's.

So be careful with "a week or two weeks off will sort it": rest is the right direction, but the 14 to 21 day line is, in the source, a diagnostic time boundary (needing less than 14–21 days of rest counts as non-functional overreaching and more than that as overtraining syndrome; the paper's wording is "by some", meaning that some diagnose it that way), not a prescription.

⚠️ If you have been tired for weeks, your results have dropped and you are sleeping badly, and you are about to cut your own volume for two weeks at most: in a study of 41 people, 68% of this group had another cause found, and the exclusion list carries myocarditis. Excluding other illness comes before cutting your own volume, not after.

#Hong Kong has an official graded heat warning — but it was not made for gyms

Hong Kong has a graded heat warning, updated hourly, that will push to your phone; it is issued by the Labour Department for employees. The Observatory's public-facing warning, by contrast, publishes no numerical threshold.

#The Labour Department's Heat Stress at Work Warning

The Labour Department's Introduction to the Heat Stress at Work Warning (document's own date 13 April 2026) states that to make it easier for employers and employees to assess the level of heat stress when working outdoors or in an indoor environment without air conditioning in hot weather, the Labour Department has established, on the basis of the HKHI values published by the Observatory and the special "extreme hot weather" alert, a Heat Stress at Work Warning in three levels — amber, red and black [Note 16].

Three further points from the same document. On update frequency: once issued, the Heat Stress at Work Warning is updated hourly, and if a higher warning level arises in the interval, the update is made earlier [Note 16] — the second half has to be carried, because an escalation does not wait for the hour. The reader will see it on the Hong Kong Observatory's official website home page and the MyObservatory mobile application; employers and employees may also learn that a warning is in force through push messages from MyObservatory or the iAM Smart mobile application.

⚠️ There are two footnotes under that table, and both have to be read, because they change how the number is to be understood. Page 1 of the document states that the Labour Department issues the Heat Stress at Work Warning on the basis of the HKHI measured by the Observatory at King's Park, and that if other HKHI monitoring stations show that heat stress in many parts of Hong Kong has reached a given level, the Labour Department will still issue the corresponding warning even though the King's Park index has not reached that level; and that if the Observatory issues a special "extreme hot weather" alert, the Labour Department will issue an amber Heat Stress at Work Warning even where the Hong Kong Heat Index has not reached 30 [Note 17].

In one sentence: those three numbers, 30, 32 and 34, are about King's Park; and the warning can be issued while King's Park is still short of them. So do not read "the King's Park index has not reached 30" as "there is no risk": the threshold is one of the triggers for issuing a warning, not a line of safety.

The scope has to be stated. The document itself says the Heat Stress at Work Warning is mainly a warning about the significant heat stress and health risk that Hong Kong's weather as a whole poses to employees working outdoors or in indoor environments without air conditioning. It is an occupational safety tool, not something issued for runners, hikers or gym-goers, and the Labour Department has made no recommendation for recreational sport. It is set out here because it is the only heat signal in Hong Kong that the reader can see on their phone, with a number, updated hourly.

The Observatory's side, by contrast, has no numbers. The Observatory's Cold and Very Hot Weather Warnings page (the page itself carries no revision date; this article uses its retrieval date of 3 August 2026) says that when Hong Kong is forecast to be generally affected by cold or very hot weather, the Observatory issues a warning calling on the public to be vigilant — and the whole page publishes no temperature or index threshold. The Observatory's own explanatory page on the Hong Kong Heat Index does carry numbers: the Hong Kong Heat Index is computed from the natural wet-bulb temperature, the globe temperature and the dry-bulb temperature, equalling 0.80Tnw + 0.05Tg + 0.15Ta; and generally speaking, when the index at King's Park is around 30 or above, the public should take appropriate precautions against the heat [Note 18].

A comparison: the index at which the Observatory tells the public to start guarding against heat (King's Park around 30 or above) and the threshold for the Labour Department's amber warning (HKHI 30) are the same number, and the same station — the Labour Department's footnote states that it works from King's Park. So the two agree not only on the figure but on where it is measured; one is written for the public and the other for employers.

The Observatory also has a product at a level below the Very Hot Weather Warning. Its section on the special weather tips for hot weather states that in some weather conditions — high temperature, high humidity or light winds — even where conditions have not reached the level for issuing a Very Hot Weather Warning, there is still a risk of heat stroke if the public do not take appropriate precautions; and that when the Observatory anticipates such conditions, it will issue special weather tips for hot weather through several channels [Note 19].

That definition settles something easily confused. The Observatory's special weather tips for hot weather are, by its own definition, issued when conditions have not reached the level of a Very Hot Weather Warning; what the Labour Department's document refers to is a special "extreme hot weather" alert — the name carries the extra word "extreme", and the direction of heat is the opposite: one is not yet hot enough for a warning, the other is extremely hot.

This article therefore does not treat the two as the same thing — two names, two opposite directions of heat; and there is no standalone page on the Observatory's website defining a product called the special "extreme hot weather" alert (see the end).

The passage in the Observatory's precautions on very hot weather most directly about exercise is four sentences: people engaged in outdoor activities should drink plenty of water and avoid over-exertion; those feeling unwell should rest in a shaded area as soon as possible; outdoor activities should as far as possible be arranged in the morning or later in the afternoon; and in extreme hot weather, vigorous exercise should be avoided [Note 19].

#Heat illness symptoms: the Labour Department's complete list, and the one judgment method it forbids

Section 6.1 of the Labour Department's Guidance Notes on Prevention of Heat Stroke at Work (third edition, April 2026) lists the symptoms of heat illness, reproduced in full at [Note 20]: fatigue; dizziness and headache; thirst; nausea and vomiting; rising body temperature; rapid breathing and difficulty breathing; palpitations and a rapid, weak pulse; localised muscle cramps and pain (especially in the feet and abdomen), which in severe cases may become generalised cramps; clammy skin, profuse sweating and pallor (common in heat exhaustion); dry, flushed, hot skin with no sweating (common in heat stroke); and confusion or even unconsciousness.

That list is not exhaustive — the source opens with "some symptoms indicating…" and uses "including" in the middle, and both are open-ended. This article has added nothing to it.

And the asterisked footnote at the end of that list is a rule published by the Hong Kong Government itself forbidding a particular method of judgment, quoted in full at [Note 20]: the symptoms of heat illness vary from person to person, and whether the affected employee is sweating profusely or not sweating should not on its own be used as the criterion for deciding whether heat stroke has occurred and whether first aid should be given.

The gym and hiking circuits pass around "if you stop sweating you have heat stroke" and "if you are still sweating you are fine"; the Labour Department states that sweating or not should not on its own settle it. That sentence is worth remembering more than the whole list.

And that footnote has a second half, because it is the one instruction to act in the section. In the same footnote the Labour Department writes that working long hours in a hot environment or doing heavy physical activity carries a risk of heat stroke, and that when the above symptoms appear, help should be sought as soon as possible and the affected employee cooled down [Note 20]. The two halves have to be read together: the first says you cannot judge by sweating, the second says what to do — seek help and cool down. With only the first half, the reader knows they cannot judge but not what comes next.

#Two authorities, two cooling methods — set out here without reconciling them, and without telling you to do either

• The Labour Department (section 6.2 of the same guidance): heat stroke can develop and worsen rapidly, so initial first aid must be given to the affected employee, the first task being to lower their body temperature until the condition improves or ambulance personnel arrive; the methods set out are spraying them with water and then using a fan or electric fan to aid evaporation, continuous wiping with a sponge or towel soaked in cold water, and placing sponges or towels soaked in cold water in both armpits and the groin; no drink is to be given to anyone who is confused; the affected employee's response to cooling must be watched continuously, and if shivering appears, cooling must be stopped immediately and the employee covered to keep warm; and the last sentence is to send them to hospital as quickly as possible [Note 21].
• The US National Library of Medicine's MedlinePlus Medical Encyclopedia (rhabdomyolysis entry, page's own review date 2 September 2025) writes in its prevention section that in heat stroke, excess clothing should be removed and the body immersed in cold water (restated here rather than quoted, because that page's copyright notice prohibits reproduction or distribution of its contents; the entry was checked and exists in English and Spanish with no Chinese version — see the end).

The two methods differ, and they differ on the handling of an emergency. For a Hong Kong reader this article takes the Hong Kong authority: the Labour Department's version carries a stopping rule — if shivering appears, stop cooling immediately — which the MedlinePlus sentence does not. But this article tells the reader to do neither — the only instruction it can give is to seek help and get to hospital, not to treat this yourself.

#Drinking water: both sources say drinking too much is itself a risk

Section 4.1.2 of the Labour Department's guidance states that, generally speaking, employers should provide employees with about 250 to 500 millilitres of cool drinking water an hour; that the higher the heat stress at work, the more water is lost through sweating, and it is recommended that they drink about 250 millilitres every 15 to 20 minutes, that is about 750 to 1,000 millilitres an hour, but that they should not drink more than 1,500 millilitres an hour, so as not to lower the salt concentration in the blood below normal [Note 22]. Two further sentences from the same guidance: drinking only when thirsty increases the risk of heat stroke, because by then the body may already be dehydrated; and for employees who have to work in a hot environment for more than two hours, employers may also consider providing drinks containing electrolytes such as sodium and potassium [Note 22]. Again: these are occupational safety figures written for employers, not a drinking prescription for the gym.

And on hot yoga, the only sourced case of harm found for this article points the opposite way to the popular advice to load up on fluid before and after class. Reynolds et al. (BMJ Case Rep 2012) record that the patient reported sweating excessively while performing 90 minutes of strenuous exertion in a humidified room heated to an ambient temperature of 40.6°C, and that after the workout she drank 3.5 litres of water before experiencing breathlessness, severe muscle cramps, nausea and general malaise, with initial investigations revealing severe hyponatraemia (120 mmol/l); the paper's own closing line is that this case highlights the dangers of overzealous fluid replacement following severe exertion in a hot environment [Note 23]. This 34-year-old woman went on to a Glasgow Coma Scale of 9/15 and a tonic-clonic seizure, requiring intubation and intensive care, and made a full recovery 5 days later.

This is a single case report, the weakest tier of study design cited in this article; and none of the sources cited here carries an injury rate for hot yoga or a figure for fluid lost per class. But it and the Labour Department's 1,500 millilitre ceiling are two independent sources pointing the same way: "more fluid must be safer" does not hold.

Nor does this article provide any millilitre figure for before or after class. Of the two sources above that carry millilitre figures, the Labour Department's are occupational safety figures written for employers, not a drinking prescription for gym-goers or hot yoga, and this article will not transplant them; while Reynolds et al. 2012 simply record what happened in one case after 3.5 litres, which is not a recommended minimum from any body. Between them, the two sources cannot answer "how much should I drink after the gym or after hot yoga".

⚠️ If you train in an unair-conditioned space in summer, run in the hills, or go to hot yoga: the live numbers you can look at are the Hong Kong Heat Index and the Heat Stress at Work Warning on MyObservatory; and remember that the Labour Department states expressly that sweating or not sweating cannot be used to judge heat stroke.

#How do you know you have it? — one sentence first: normal urine colour rules nothing out

Rhabdomyolysis cannot be told apart at home, and the symptom most people use to reassure themselves is, in the literature, an insensitive indicator.

#Urine colour

Tietze and Borchers (Sports Health 2014) state that rapid clearance of myoglobin from the urine makes it a less sensitive indicator of exertional rhabdomyolysis, and that it should not be used as the sole objective diagnostic marker [Note 1].

Three further records from the same body of literature:

• Rawson et al. (2017): myoglobinuria without rhabdomyolysis has been described in ultra-marathon runners [Note 3].
• The same paper, on an eccentric exercise experiment in which participants' CK rose sharply: none experienced visible myoglobinuria [Note 3].
• The two figures on StatPearls (NBK448168, the page's own "Last Update: July 7, 2025") do not agree with each other, and both are reported here: its History and Physical section says dark urine is seen in about 30% to 40%; the Evaluation section on the same page says reddish-brown urine from myoglobinuria may be present in about 50% of cases [Note 2]. Both figures point the same way: at least half of people will not see a change in urine colour.

The same page states of the triad that even though muscle pain, weakness and tea-coloured urine are the characteristic triad of rhabdomyolysis, these findings are seen in less than one-half of patients; that muscle pain is the most common presenting symptom, reported in about 50% of adults; that dark-coloured urine is seen in about 30% to 40%; that weakness typically involves proximal muscle groups; and that non-specific symptoms such as muscle cramps, stiffness, muscle swelling, weakness, malaise, abdominal pain, nausea, palpitations and fever may be present [Note 2].

And what StatPearls puts immediately after that passage is its own conclusion: a high index of suspicion is sometimes necessary when diagnosing rhabdomyolysis [Note 2]. The same passage also says that depending on the cause, the patient may have the following history (all the items that sentence lists): illicit drug use, insect bites, heat exertion, recent surgical procedures, accidents, recent increases in the dosage of regularly used medications, new medications, or over-the-counter supplements. That is a history list, not a self-check list — the source's own sentence opens with "Depending on the cause".

So the claim that dark brown urine is the most characteristic sign points the wrong way, and points wrong on the reassuring side. A reader in severe muscle pain with normal urine colour who therefore goes back to the gym is exactly why this section exists — and the prescription the source itself writes is to raise suspicion, not to work down a list.

#Three authorities, three different lists

No two lists agree completely, and all three state that they are not exhaustive. Three items make the point: muscle swelling appears in only two of the three sources, reduced urine output in only two, and fever in only two.

So what this article gives the reader is a combined list, taking every item from all three sources and marking where each comes from: muscle pain, muscle weakness, dark urine, muscle swelling, reduced urine output, fever, tiredness, plus the cramps, stiffness, malaise, abdominal pain, nausea, palpitations, confusion, agitation and delirium that StatPearls separately lists, and localised bruising and tenderness; plus the three items unique to that MedlinePlus page — muscle tenderness, joint pain and seizures, and unintentional weight gain. (⚠️ "Seizures" and the "cramps" above are two different things; do not confuse them.) Even taking every item from all three sources, this list is still not complete — all three state that they are not exhaustive. Not being on it does not mean it does not matter.

#Symptoms can start days later

healthdirect (Australia's national health information service, funded by the Australian federal and state governments; the page's own "Last reviewed: June 2025") states in the banner at the top of the page: symptoms of rhabdomyolysis may not start for hours or days after your muscle injury [Note 24].

The actual timings in the literature: the spin case series was within a week of the first class; the physical education case of 119 students was muscle pain and dark urine 2 to 4 days after the exercise; the 12-year-old boy's case was dark urine 2 days after and CK peaking on day 4. Which is to say: "nothing happened that evening" is not a sign that you are through.

#How do you tell ordinary muscle soreness (DOMS) from rhabdomyolysis?

This article provides no method of telling them apart, because not one of the sources cited here provides a method that can be used at home.

The popular version runs that ordinary muscle pain still lets you walk and clears in a few days, while rhabdomyolysis hurts so much you cannot move. That sounds reasonable, but it is an exclusion rule: someone in severe pain who can still walk will find in it the answer "I am the first kind". The literature works the other way round — Tietze and Borchers state that significantly elevated CK must be present for the diagnosis, and that the diagnosis should be made in association with the presenting clinical syndrome of muscle weakness, swelling, pain and, occasionally, darkening of the urine [Note 1]. CK is a blood result, and the reader does not have one.

And on how high CK has to be, four sources give four answers, set out here without reconciling them:

In one sentence: there is not even agreement on how high counts, so this is not something a symptom checklist at home can settle. The claim that "above 1,000 U/L is a diagnosis" is one source's rule of thumb taken for a rule.

⚠️ If this is your first time training so hard you cannot sleep, and you are telling yourself it is probably just DOMS: this article will not rule out rhabdomyolysis for you, because not one source can.

#When to seek care, where to go, and what it costs

The source that speaks to the public most directly about urgency uses one word: "urgently". Hong Kong has published times to care, but they are written for clinicians — among the Hong Kong government pages and documents examined for this article, not one publishes a triage timetable for members of the public to use at home.

#The published levels of help

Rhabdomyolysis — healthdirect (reviewed June 2025). One section of that page is headed with the question of when to call an ambulance or go to the emergency department, and its text states: seek medical attention urgently if you have symptoms of rhabdomyolysis — muscle pain, muscle swelling, muscle weakness and dark urine; and symptoms may not start for hours or days after the muscle injury [Note 24].

⚠️ How that sentence is read matters. Its four symptoms are strung together with "and", which read literally suggests all four are needed. But the same body of literature has already ruled that reading out: StatPearls states that the full triad is seen in fewer than half of patients, and Tietze and Borchers state that urine colour is an insensitive indicator. So that sentence is not to be treated as a checklist requiring all four before going to A&E. healthdirect's own symptom list is written open-endedly too: the symptoms of rhabdomyolysis will depend on the cause, but include muscle pain or swelling, muscle weakness, fatigue, dark red to brown urine, and fever [Note 24].

Two further sentences from the same page are equally direct: it is important to get treatment early to avoid life-threatening complications; and early diagnosis and treatment increases the chance of a full recovery [Note 24].

On the US National Library of Medicine's MedlinePlus, the whole section on when to contact a health professional is a single sentence, to the effect that anyone with symptoms of rhabdomyolysis should contact their health care provider — with no stratification by time (restated rather than quoted, for the reason above and at the end).

Heat stroke — the Hong Kong Observatory's precautions on very hot weather state: if symptoms such as dizziness, headache, nausea, shortness of breath and confusion appear, one should rest and seek help immediately, and seek medical attention as soon as possible [Note 19].

That sentence is itself a two-tier stratification: rest and seek help immediately → seek medical attention as soon as possible. And it closes with "symptoms such as", which is likewise open-ended and not exhaustive.

#The actual route and charges in Hong Kong

The Hospital Authority's accident and emergency services page states that the accident and emergency departments of the eighteen public hospitals under the Hospital Authority provide consultation and treatment for patients needing emergency services, and that patients whose condition is not urgent should seek care at a public or private clinic. Triage has five categories: critical, emergency, urgent, semi-urgent and non-urgent.

Do the arithmetic (entirely from the figures in the table above): an eligible person who suspects rhabdomyolysis and goes to accident and emergency —

• If triaged as Category I or Category II: $0 (exempted).
• If triaged as Category III to V: $400.
• If they leave after triage without seeing a doctor and apply for a refund within 24 hours: $400 − $350 = $50 paid in the event.
• If admission is needed (acute bed) for three days, having been triaged as Category III to V (so the $400 attendance charge applies): $400 + $300 × 3 = $1,300, subject to the protection of the annual charge cap of ten thousand dollars.

Two assumptions in that sum have to be stated: first, it is calculated at the adult bed charge; second, it assumes triage as Category III to V, where the $400 attendance charge applies. Note 4 of the Hospital Authority's fee table states that children under twelve and infants who cannot be discharged at the same time as their mothers pay half the inpatient charge for the class of bed they occupy, with other charges the same as for adults. The same situation for a child under twelve would be $400 + $150 × 3 = $850, likewise protected by the annual cap. If triaged as Category I or II, the $400 attendance charge is waived, and three days of admission comes to $300 × 3 = $900 for an adult and $150 × 3 = $450 for a child under twelve — the triage category, like the class of bed, is an unstated assumption in this sum.

This sum is the most practical thing this article can offer: if you are triaged into the two most urgent categories, the price of "if in doubt, get it looked at" is $0; and if you are seen once without admission, the price is capped at $400 (for an eligible person not triaged as Category I or II). But once admission is needed the price is more than $400 — as calculated above, an adult triaged as Category III to V staying three days comes with the attendance charge to $1,300.

#The admission threshold and the return-to-training protocol are for clinicians; this article notes only that they exist

• The admission threshold. Tietze and Borchers (2014) is the only source found here that publishes one: for an athlete with severe symptoms (CK greater than 5 times the upper limit of normal or darkening of the urine), hospital admission is indicated for intravenous hydration with normal saline (1-2 L/h) maintaining a urine output of 200 mL/h [Note 25]. That is written for a doctor who already has a blood result; the reader has no CK value — and using the "or darkening of the urine" half in reverse, to rule oneself out, is exactly the error of the previous section.
• The return-to-training protocol. The same paper reproduces the staged return protocol of the US military's CHAMP (Consortium for Health and Military Performance), built around repeat CK and urinalysis at 72 hours. This article does not reproduce that protocol: every step of it depends on laboratory values the reader does not have, and one of its low-risk conditions at the 72-hour gate is a negative urinalysis; another passage of the same paper describes a low-risk athlete as one where "the urine is clear" — and a reader at home judging by eye whether their urine is clear and applying such a description is taking an insensitive indicator for a pass. The same paper also states that there are no evidence-based guidelines for return to play after an episode of exertional rhabdomyolysis [Note 25].
• The direction of treatment (StatPearls): the goal of rhabdomyolysis management is to maintain adequate fluid resuscitation and prevent acute kidney injury [Note 2]. healthdirect likewise writes that treatment is given in hospital through intravenous fluids, and that severe cases may need medication, surgery or dialysis. These are things done in a hospital, not at home.

⚠️ If you are standing outside the accident and emergency department working out whether it is worth $400: triage as critical or emergency is free; and if you change your mind and leave after triage, $350 is refundable within 24 hours.

#How do you lower the risk? — what has evidence and what does not

The strongest meta-analysis of sports injury prevention found for this article supports strength training and does not support stretching.

Lauersen et al. (Br J Sports Med 2014) analysed 25 randomised controlled trials, 26,610 participants and 3,464 injuries, and found: stratified exposure analyses proved no beneficial effect for stretching (relative risk 0.963, 95% confidence interval 0.846–1.095), whereas multiple exposures gave 0.655 (0.520–0.826), proprioception training 0.550 (0.347–0.869) and strength training 0.315 (0.207–0.480); both acute injuries (0.647) and overuse injuries (0.527) could be reduced by physical activity programmes; and strength training reduced sports injuries to less than a third, while overuse injuries could be almost halved [Note 26].

Which is to say: the stretching arm's confidence interval crosses 1 (0.846 to 1.095), which is a null result rather than "the evidence is mixed"; and the gym itself — strength training — is the largest effect in that analysis. Saying "the evidence on stretching for injury prevention is mixed" is putting it too gently against these numbers.

On how fast to add load, this article uses a qualitative statement rather than a percentage — the reason is in the paragraph after. healthdirect (reviewed June 2025) states in its prevention section that you can prevent exercise-induced rhabdomyolysis by slowly building up resistance training [Note 27].

That sentence does not stand alone; the same section has three more, all reproduced here, because one of them is the ceiling on the whole section: you can lower your chance of developing rhabdomyolysis by staying hydrated; talk with your doctor or pharmacist about any medicines you take that may increase your chance of developing rhabdomyolysis; and you cannot prevent all causes of rhabdomyolysis, such as when it is caused by an underlying health condition or an accident [Note 27].

The third sentence is the most important in this section: the source states its own ceiling on prevention. So this section is not to be read as a list of things that, done together, mean nothing will go wrong. And the second sentence joins back to the statins passage above: on medication, the source points to a doctor and a pharmacist, not to adjusting your own drugs.

The widely circulated rule of not increasing weekly training volume by more than 10% is not unsourced — it has a name, and it has been put through a randomised controlled trial, which found it did not reduce injuries. In the literature its formal name is "the 10% rule" or "the ten percent training rule". Buist et al. (BMC Musculoskelet Disord 2007, the GRONORUN trial design paper, PMID 17331264) state that to minimise the risk of a running-related injury, an increase of training duration or intensity by no more than 10% is recommended, that is the 10% rule; however, so far no studies have examined the effect of increasing training load in this way on runners' injury risk [Note 28].

The second sentence has to be read with it: the authors state themselves that at that time no study had tested the rule.

So they went and tested it. Buist et al. (Am J Sports Med 2008;36(1):33-9, PMID 17940147) randomised 532 novice runners into two groups: one on the usual 8 week programme, the other on a 13 week graded programme stated to be based on the 10% training rule. The result: the graded training programme was not preventive for sustaining a running-related injury (chi-square = 0.016, df = 1, P = .90); the incidence of running-related injury was 20.8% in the graded training programme group and 20.3% in the standard training programme group [Note 29].

The two figures have to be read together: 20.8% against 20.3%, N = 532, followed for 13 weeks, with injury defined as musculoskeletal discomfort of the lower limb or back causing a stoppage of running for at least a week. In one sentence: the group that followed the 10% rule was injured in the same proportion as the group that did not.

⚠️ The scope has to be stated, because it determines how much this result has to do with you. That trial measured adding 10% a week to running time, in novice runners preparing for a four-mile (6.7 kilometre) event; it is not a trial of the rate of loading in resistance training or weightlifting. So what can be said is: the rule has a source, it has been tested in novice runners, and it tested negative; as for how fast to add weight in the gym, not one of the sources cited here has tested the figure of 10%. This article therefore prescribes no percentage for adding load, and keeps only healthdirect's qualitative sentence above.

Likewise not cited here are "48 hours between sessions for the same muscle group" (what Kreher and Schwartz's table 5 writes is a rest period of greater than 6 hours between exercise bouts, which is a different matter) and "warm up for 5–10 minutes" (none of the sources cited here prescribes a warm-up duration).

⚠️ And Kreher and Schwartz's table 5 is more than that one row, which this section has a duty to give. That table is headed with preventive measures for non-functional overreaching and overtraining syndrome, and has twelve items in all, of which the row quoted above is one. The other eleven are reproduced in full at [Note 30]: periodisation of training; tapering for competition; adjusting training volume and intensity based on performance and mood; ensuring adequate calories for the training load; ensuring adequate hydration; ensuring adequate carbohydrate ingestion during exercise; ensuring adequate sleep; promoting mental toughness or resilience as a buffer; abstinence from training following infection, heat stroke or heat stress and periods of high stress; avoiding extreme environmental conditions; and using the Profile of Mood States (or stress level) and altering training load accordingly. The item on abstaining from training after infection, heat stroke or heat stress and periods of high stress joins directly to the heat section above; and table 5 as a whole is a prompt list for clinical and coaching staff, reproduced here because not one of its items depends on a laboratory value the reader does not have.

There is an official graduated schedule, but it is for heat acclimatisation, not for building strength. Sections 4.6.2 to 4.6.4 of the Labour Department's guidance state that where an employee has never worked, or has not worked for more than a month, in a hot environment, the employer should arrange a heat acclimatisation period of at least 5 days, with work in the hot environment on the first day not exceeding 20% of normal working hours and a further 20% added each day thereafter; that where an employee has been away from work in a hot environment for two weeks to a month, on returning the employer should arrange a heat acclimatisation period of at least 4 days, with the first day not exceeding 50% of normal working hours and a further 20% added each day thereafter; and that past research has shown that more than half of fatal heat stroke accidents involved employees not acclimatised to working in a hot environment, with the accidents occurring during their first few days at work [Note 31].

There is a reason for reproducing all three passages. The first, 4.6.2, is written for people who have never worked or have been away for more than a month in a hot environment — which is the closest box to the reader from the opening of this article who has been off for a few months and wants to catch up — and it starts at 20% on day one. The middle passage, 4.6.3, is for a different group — away for two weeks to a month and now returning — and starts at 50% on day one, unlike 4.6.2. The grading is by how long you have been away, not a single line: "a few months" falls in the 4.6.2 tier, not 4.6.3.

This is an arrangement of working hours in heat, and this article will not repackage it as a training prescription. But it carries one observation that maps directly onto the gym: the incidents cluster in the first few unacclimatised days — the same shape as "unaccustomed strenuous exercise" in the rhabdomyolysis literature.

#Recovery methods: each anchored to its source, with no overall rating

⚠️ If you want to know what actually prevents injury: in that meta-analysis, strength training itself (relative risk 0.315) is the largest effect, and stretching is nil.

#Drugs, supplements and the law: only the few that bear directly on injury

The evidence on supplements as a whole is dealt with elsewhere — see 〈The evidence on supplements〉. This section covers only the few that appear directly in the rhabdomyolysis literature or in Hong Kong law.

Statins, non-steroidal anti-inflammatory drugs and ephedrine — see the section on which situations carry more risk, above. Of the six cases of creatine-associated rhabdomyolysis Rawson et al. record, four of the men were ingesting ephedrine [Note 9].

Creatine: the literature points the opposite way to the popular account. The abstract of Rawson et al. (2017) states that creatine monohydrate does not appear to be a precipitating factor for exertional rhabdomyolysis [Note 32]. The same paper writes that creatine supplementation reduces muscle damage and inflammation, both of which would predict a lower risk of rhabdomyolysis rather than a higher one, and traces the origin of the myth: the deaths of three US National Collegiate Athletic Association wrestlers within two months in 1997 (with official causes given respectively as unknown, hyperthermia and rhabdomyolysis), from which a myth was born [Note 32].

One point bearing directly on reading a laboratory report: creatine can raise blood creatinine, which is a marker of kidney function — but that rise does not happen in everyone. Antonio et al. (J Int Soc Sports Nutr 2021) state that one must exercise caution when using blood creatinine and estimated creatinine clearance or glomerular filtration rate in individuals who consume high meat intake or supplement with creatine [Note 33]; the same paper cites the review by Persky and Rawson: 12 studies with no rise, 8 with a rise that remained within the normal range, and 2 above the upper limit of normal. ⚠️ Declaration of interests: that paper's own competing interests statement records that the first author is the chief executive officer of the International Society of Sports Nutrition, which receives support or sponsorship from companies that manufacture or sell creatine products, and that several co-authors sit on the scientific advisory boards of creatine manufacturers. On the popular advice to stop creatine for a week before a blood test: Antonio et al. 2021 nowhere proposes any stopping period, and says only that interpretation calls for caution, so this article makes no statement about it — what to do before a test is for the doctor ordering it. How to read the numbers on a laboratory report is a subject of its own; see 〈Reading laboratory and imaging reports〉.

Anabolic steroids in Hong Kong are not "a Hospital Authority prescription drug" — the Hospital Authority is a hospital operator, not a drug regulator. The correct legal position has three layers:

1. Part 1 of the Poisons List in Schedule 10 to the Pharmacy and Poisons Regulations (Chapter 138A, consolidated version dated 3 July 2026): steroid compounds with androgenic, oestrogenic or progestogenic activity, and their esters, save where contained in an oral preparation intended for contraceptive use only and containing no more than a specified quantity per dose; the exception names ten substances with a maximum per dose (desogestrel 0.15 mg, gestodene 0.10 mg, levonorgestrel 0.25 mg, lynestrenol 2.50 mg, drospirenone 3.00 mg, ethinyloestradiol 0.05 mg, norgestrel 0.50 mg, norethisterone 1.00 mg, mestranol 0.05 mg, norgestimate 0.25 mg) [Note 34]. ⚠️ That entry is written generally, covering more ground than "anabolic steroids" and including oestrogens and progestogens; and it carries its own quantity exception for oral contraceptive preparations.
2. Schedule 3 to the same Regulations — headed as substances that may be sold by retail only in accordance with a prescription given by a registered medical practitioner, registered dentist or registered veterinary surgeon. That is, prescription drugs.
3. Possession is regulated, but not an offence unconditionally — section 23 has two subsections and both must be read. Section 23 of the Pharmacy and Poisons Ordinance (Chapter 138, consolidated version dated 14 May 2026), headed as prohibiting possession of Part 1 poisons, is reproduced in full at [Note 35]: subsection (1) provides that except in accordance with the provisions of the Ordinance no person shall possess any poison listed in Part 1 of the Poisons List, and that the burden of proof lies on the person possessing it; while subsection (2) provides that where such a poison was obtained in the circumstances listed in section 28(1)(a), (b), (c) or (d), the Ordinance does not prohibit any person from possessing it.

⚠️ Subsection (2) is the most important sentence in that passage, and it is easily left out. Section 28(1) is headed as exemptions in respect of medicines, and the circumstances listed in paragraphs (a) to (d) include medicines supplied by a registered medical practitioner for the purposes of medical treatment, by a registered dentist for the purposes of dental treatment, or by a registered veterinary surgeon for the purposes of animal treatment, and medicines dispensed by an authorised seller of poisons on premises duly registered under the Ordinance. Which is to say: where a drug of this kind is prescribed by a registered doctor or dispensed by a licensed pharmacy, the Ordinance states in terms that possession is not prohibited. A reader taking prescribed testosterone or hormone medication should not conclude from this section that they are breaking the law. The burden of proof under subsection (1) still lies on the person in possession — that is, they must be able to produce the prescription or the source of the dispensing; and what the penalty addresses is possession outside those circumstances. The penalty is in section 34 of the same Ordinance: any person committing an offence under the Ordinance is liable on conviction, unless a penalty is expressly provided otherwise, to a fine at level 6 and to imprisonment for 2 years [Note 35]. And the amount of a level 6 fine is in Schedule 8 to the Criminal Procedure Ordinance (Chapter 221): level 6, $100,000.

"Enhanced Athlete" type SARMs products: Hong Kong has one official characterisation, but it is about registration status, not poisons classification. The Drug Office of the Department of Health's entry of 23 October 2017 in its listing of products found to contain undeclared Western medicines (relaying an alert from Singapore's Health Sciences Authority) has, on the Chinese page, only one sentence of body text besides the heading: in Hong Kong, the above products are not registered pharmaceutical products — and the page then says that for details the English version should be consulted, that is, the Chinese page itself directs the detail to the English. The English version separately records that the three products were labelled as containing GW501516 (cardarine), LGD-4033 (ligandrol) and YK-11, and that GW501516 was found to cause cancers in mice and rats during animal safety studies, that all related research was terminated after 2006, and that the World Anti-Doping Agency issued an alert about it in 2013 [Note 36].

⚠️ One finding with a limit of scope, in passing: across the Drug Office of the Department of Health's listing of products found to contain undeclared Western medicines from 2013 to 2026 (1,824 items in Chinese and English combined) and its press releases from 2015 to 2026, there is not one local Hong Kong action concerning a sports or fitness supplement; of the 77 local Hong Kong cases over the same period, 39 concerned slimming products. That means only that these two listings contain none, not that Hong Kong has no problem products.

⚠️ If someone in the gym tells you these are available online and are nothing to worry about: section 28(1), headed as exemptions in respect of medicines, has four paragraphs, (a) to (d), of which only two are set out above (supply by a registered medical practitioner, dentist or veterinary surgeon, and dispensing by a licensed pharmacy); possessing a Part 1 Poisons List substance outside those four circumstances carries the penalty written into the Ordinance — a level 6 fine of a hundred thousand dollars plus two years' imprisonment, with the burden of proof on the person in possession, meaning you must be able to produce the source. Conversely, section 23(2) states that possession of what was obtained in the circumstances listed in section 28(1)(a) to (d) is not prohibited.

#What to do next

This article will not judge for you whether something is wrong — it cannot, and neither can any of the sources cited here. What it can do is narrow down which road you take next.

First, delete the self-exclusion rule "my urine colour is normal" from your head. It is the single sentence this article most wants to take apart. Dark urine is seen in only 30% to 50% of patients, and the full triad in fewer than half; and severe muscle pain with normal urine colour is precisely the combination that sends people back to the gym. The direction the source itself gives is to raise suspicion, not to work down a list.

Second, if you now have any one of severe muscle pain, muscle swelling, muscle weakness or a change in urine colour — not all four — see a doctor. The only source that speaks to the public directly about urgency uses the word "urgently". And in Hong Kong the price of that step is published: triage as critical or emergency is free, otherwise $400 per attendance, and if you leave after triage without seeing a doctor you may apply within 24 hours to reclaim $350. The sum you are doing at the door is capped at $400.

Third, if your problem is weeks of fatigue and falling results, get investigated first rather than cutting your own volume first. In that study of 41 people, 68% of this group had another cause found, and the exclusion list carries myocarditis, thyroid disease and iron deficiency. "I am just overtrained" is a conclusion to be reached after a doctor has excluded other illnesses. Which tests to run is for the doctor — the source itself states that the extensive and costly battery should be considered only in the appropriate setting.

Fourth, back at training itself, this article has only three sourced things to say: strength training itself is the largest effect in the strongest prevention meta-analysis (relative risk 0.315) and stretching is nil; building up resistance training slowly can prevent exercise-induced rhabdomyolysis (healthdirect's qualitative statement, with no percentage from this article, because the trial that tested the 10% rule found it did not work, and it tested running rather than lifting); and the same source states itself that not all causes can be prevented.

Fifth, before training in an unair-conditioned space in summer, look at MyObservatory. The Hong Kong Heat Index and the Heat Stress at Work Warning are the only heat signal in Hong Kong with a number, updated hourly — even though it was made for employees rather than for you. And the Labour Department's rule is worth remembering on its own: you cannot judge heat stroke by whether or not someone is sweating.

On whether supplements are useful in general, see 〈The evidence on supplements〉; and if your pain is in the low back rather than the limbs, that is a different road — see 〈Low back pain〉.

#Frequently asked questions

My muscles hurt so much after training that I can barely move, but my urine looks normal — can I ignore it?

Normal urine colour cannot rule out rhabdomyolysis. Tietze and Borchers (2014) state that myoglobin is cleared rapidly from the urine, making it a less sensitive indicator that should not be used as the sole objective diagnostic marker; StatPearls measured dark urine in about 30–40% of patients (about 50% in another section of the same page). What healthdirect (reviewed June 2025) writes for anyone with symptoms of rhabdomyolysis is "Seek medical attention urgently".

Nothing happened the evening after training — am I through?

No. healthdirect states that symptoms may not start for hours or days after the muscle injury. From the case literature: the physical education case of 119 students was 2–4 days later; the 12-year-old boy's case was dark urine 2 days later with CK peaking on day 4; the spin case series was within a week of the first class.

I am persistently tired and my results have dropped — is that overtraining?

This is the conclusion least suited to reaching alone. Kreher and Schwartz (2012): where underperformance appears without a period of rest, overtraining syndrome cannot be diagnosed, and the diagnosis can be made only in retrospect. In the study they cite (Reid et al. 2004, 41 people), 68% had a cause found — most commonly partial humoral immune deficiency 28%, unresolved viral infections 27% and non-fasting hypoglycaemia 28%; and the exclusion list includes thyroid disease, adrenal disease, diabetes mellitus, iron deficiency with or without anaemia, myocarditis, hepatitis and eating disorders. But note: that 68% is the result after a whole battery of extensive and costly tests, which the source itself says should be considered only in the appropriate setting, and which tests to run is for a doctor. Exclusion first, rest second.

How do I tell ordinary muscle soreness from rhabdomyolysis?

This article provides no method, because not one of the sources cited here provides a method that can be used at home. The diagnostic step in the literature is a blood CK plus clinical judgment taken together, and on how high CK has to be, four sources differ (see the table in the section on how you know you have it).

How many people are injured in gyms in Hong Kong?

Centre for Health Protection, Report of Unintentional Injury Survey 2018: of 57,000 sports injury events across Hong Kong, "fitness training" accounted for 4.1%, that is 2.3, in thousands, of events over 12 months; seven rows in the same table are above fitness training, six of them named sports (basketball 22.9%, football 15.8%, jogging 11.3%, cycling 10.4%, hiking 7.6%, badminton 4.5%) and the seventh a residual category of other sports at 11.1%; and the leading direct mechanism was overexertion (51.8%). That report carries no figure for rhabdomyolysis at all, and "overexertion" is an injury coding category that cannot be taken for rhabdomyolysis.

Is there an official signal to check before training in an unair-conditioned space in summer?

There are two, with different thresholds. The Labour Department's Heat Stress at Work Warning grades the Hong Kong Heat Index at 30, 32 and 34 into amber, red and black, updates hourly once issued, and can be received as a push through MyObservatory or iAM Smart — but it is an occupational safety tool, aimed only at employees working outdoors or in indoor environments without air conditioning, and does not cover recreational sport. The Observatory's Very Hot Weather Warning publishes no numerical threshold, but its precautions carry one sentence: in extreme hot weather, vigorous exercise should be avoided.

Is "you have heat stroke once you stop sweating" correct?

Section 6.1 of the Labour Department's Guidance Notes on Prevention of Heat Stroke at Work (third edition, April 2026) states that the symptoms of heat illness vary from person to person, and that whether the affected employee is sweating profusely or not sweating should not on its own be used as the criterion for deciding whether heat stroke has occurred and whether first aid should be given.

How much should I drink before and after hot yoga?

This article gives no drinking prescription, and the direction is worth noting: the only sourced case of hot yoga harm found here is a 34-year-old woman who, after 90 minutes of strenuous exercise at 40.6°C, drank 3.5 litres of water and had a blood sodium of 120 mmol/l, a seizure, intubation and intensive care. The Labour Department's guidance separately states that one should not drink more than 1,500 millilitres of water an hour, so as not to lower the salt concentration in the blood below normal. More is not safer.

How much does a trip to accident and emergency cost?

Hospital Authority fees page (in effect from 1 January 2026): 400 dollars per attendance for eligible persons, with those triaged as Category I (critical) and Category II (emergency) exempted; 2,100 dollars for non-eligible persons. If you leave after triage without seeing a doctor, an application through HA Go or the accident and emergency registration counter within 24 hours allows an eligible person to reclaim 350 dollars (that is, 50 dollars paid in the event). There is also an annual cap of ten thousand dollars on public healthcare service charges, with no means test.

#Notes: the original texts

[Note 1] Tietze DC, Borchers J, Sports Health 2014;6(4):336-9: "Rapid clearance of myoglobin from the urine makes it a less sensitive indicator for ER, and it should not be used as the sole objective diagnostic marker." and "Significantly elevated CK must be present for the diagnosis of ER but should be made in association with the presenting clinical syndrome of muscle weakness, swelling, pain, and occasionally, darkening of the urine"

[Note 2] StatPearls, NBK448168 (Last Update: July 7, 2025): "Even though muscle pain, weakness, and tea-colored urine are the characteristic triad of rhabdomyolysis, these findings are seen in less than one-half of patients. Muscle pain is the most common presenting symptom and is reported in about 50% of adults with rhabdomyolysis, and dark-colored urine is seen in about 30% to 40%. Weakness typically involves proximal muscle groups. Nonspecific symptoms like muscle cramps, stiffness, muscle swelling, weakness, malaise, abdominal pain, nausea, palpitations, and fever may be present." "A high index of suspicion is sometimes necessary when diagnosing rhabdomyolysis." "illicit drug use, insect bites, heat exertion, recent surgical procedures, accidents, recent increasing dosages of regularly used medications, new medications, or over-the-counter supplements" The Evaluation section: "reddish-brown urine from myoglobinuria may be present in about 50% of cases" "For hospitalized individuals who develop AKI in the setting of rhabdomyolysis, the mortality rate is 30% to 50%." "If identified early, the prognosis of AKI from rhabdomyolysis is relatively benign." "Statins are the most common pharmaceuticals to cause rhabdomyolysis. Up to 10% of patients taking statins experience muscle pain." "The goal of rhabdomyolysis management is to maintain adequate fluid resuscitation and prevent AKI."

[Note 3] Rawson ES et al., Sports Med 2017;47(Suppl 1):33-49: "However, myoglobinuria without rhabdomyolysis has been described in ultra-marathon runners" and, on the eccentric exercise experiment: "none experienced visible myoglobinuria"

[Note 4] Kreher JB, Schwartz JB, Sports Health 2012;4(2):128-38: "Differentiation of NFO and OTS is clinically difficult and can be made often only after a period of complete rest. The difference between the 2 is based on time to recovery and not necessarily the degree or type of symptoms." "If an athlete presents with underperformance without a period of rest and recovery, OTS cannot be diagnosed." "The diagnosis from history can be made only in retrospect given the definitions of NFO and OTS."

[Note 5] Meeusen R et al. (joint consensus statement of the European College of Sport Science and the American College of Sports Medicine), Med Sci Sports Exerc 2013;45(1):186-205, abstract: "Currently, several markers (hormones, performance tests, psychological tests, and biochemical and immune markers) are used, but none of them meet all the criteria to make their use generally accepted." and "there is no scientific evidence to either confirm or refute this suggestion"

[Note 6] Centre for Health Protection, Department of Health, Report of Unintentional Injury Survey 2018:

A sports-injury-related injury event means the injured person was hurt while engaged in a sports-related activity (for example, competing, taking part in sport recreationally, or warming up). (our translation from the Chinese original)

Chinese original:

「與運動損傷有關的損傷事件是指傷者在進行與運動有關的活動（例如比賽、以消閒性質參與運動、熱身）時受傷。」

The footnote:

Under ICECI, overexertion means a load that causes discomfort or injury to the body, and it can be divided into acute and non-acute. Acute overexertion is a situation occurring over a short and sudden course, an example being spraining an ankle while lifting something heavy. Non-acute overexertion is a situation caused by the cumulative effect of repeated activity, with gradual and/or delayed onset, an example being joint strain caused by marathon running or rowing. (our translation from the Chinese original)

Chinese original:

「根據ICECI，過度勞累是指對身體造成不適或損傷的負荷，它可分為急性及非急性。急性過度勞累是發生過程短暫而急促的情況，例子包括提起重物時扭傷足踝。非急性過度勞累是由多次活動累積效應引致，逐漸和/或延遲發作的情況，例子包括馬拉松或划艇運動所導致的關節勞損。」

[Note 7] Centre for Health Protection, Department of Health, Physical Activity page (page's own date 15 April 2025):

They should also do muscle-strengthening activities at moderate or greater intensity targeting all major muscle groups on two days or more each week, which brings additional health benefits. / 14.8% of people aged 18 and above are insufficiently physically active, 16.0% among women and 13.4% among men. (our translation from the Chinese original)

Chinese original:

「他們還應每星期有兩天或以上，進行中等或更高強度針對所有主要肌肉群的強化肌肉活動，這能帶來額外健康裨益。」 「有14.8%的18歲或以上人士體能活動量不足，女士中有16.0%，男士中有13.4%。」

[Note 8] Rawson ES et al., Sports Med 2017: "Reduced hydration impairs the ability of the kidneys to clear myoglobin and other potential myotoxic substances, consequently increasing the risk of myoglobin precipitation, renal cast formation, and possibly local factors intrinsic to the kidney such as oxidative stress (ischemia–reperfusion), increasing the risk for renal failure. Although a risk factor, dehydration does not have to be present for clinically relevant rhabdomyolysis to manifest" and "The muscle contractions that cause the most muscle damage are those where the muscle lengthens as it is attempting to contract (also referred to as eccentric in classical literature), for example lowering a weight during a biceps curl. In the gym, these contractions are referred to as "negatives." High-force (high-resistance) lengthening contractions place strain on the muscle fibers and cause damage to protein structure, releasing muscle proteins into the circulation"

[Note 9] The same, risk factors: "Several factors can increase the risk of exertional rhabdomyolysis, including an increase in exercise intensity/duration or using different muscle groups (unaccustomed strenuous exercise), muscle contraction type (eccentric/lengthening > concentric), infection, medication use, dietary factors (e.g., hydration), environmental factors (extremes of heat and cold), sex (males > females), and genetic factors"; statins: "~0.1% of all users will experience rhabdomyolysis, defined as a CK elevation to >10 times the upper limit of normal"; painkillers: "can reduce renal perfusion, leading to a depressed glomerular filtration rate"; genetics: "are not typically associated with the first bout of exertional rhabdomyolysis after strenuous unaccustomed exercise"; ephedrine: "Four of the men were ingesting ephedrine"

[Note 10] Yow LPS et al., Cureus 2021;13(7):e16352: "there has been an increased occurrence of spin-related rhabdomyolysis observed among previously fit adults after undertaking their first spin bike class session. They present with the triad of myalgia, muscle weakness, and dark tea-colored urine within a week of their first spin session." Ramme AJ et al. (2016) record three cases occurring in "deconditioned individuals".

[Note 11] Rawson ES et al., Sports Med 2017: "only a small percentage of individuals exposed to the same exercise conditions experience rhabdomyolysis"; on marathons: "40% showed evidence of acute kidney injury … which resolved in the next 24 h"; on the Comrades: "only 19 cases of acute renal failure were reported". The incidence figures: Tietze & Borchers 2014, "an incidence of approximately 29.9 per 100,000 patient years"; military recruits, "22.2 cases of exertional rhabdomyolysis per 100,000 military trainees per year".

[Note 12] Kreher JB, Schwartz JB, Sports Health 2012: "In one of the few studies describing evaluation of underperforming athletes, a cause for repeated infections and/or fatigue was found in 68% of regional- or higher-level athletes. Ninety-three percent of the athletes reported decreases in performance." "This evaluation was significant for a more extensive and costly laboratory evaluation, including B12, folate, serology for viral hepatitis, toxoplasmosis, cytomegalovirus/Epstein-Barr virus titers, Epstein-Barr virus DNA in saliva, serum and salivary immunoglobulins (serum immunoglobulin G subclasses and specific serum immunoglobulin E to aeroallergens), and antinuclear antibodies. Such extensive testing should be considered only in the appropriate setting." "The list of organic diseases that can result in underperformance is extensive and not limited to the following: undiagnosed asthma/bronchial hyperreactivity, thyroid disease, adrenal disease, diabetes mellitus or insipidus, iron deficiency with or without anemia, infection (myocarditis, hepatitis, HIV, etc), and malnutrition (due to eating disorders, celiac sprue, etc)."

[Note 13] Reid VL, Gleeson M, Williams N, Clancy RL, Br J Sports Med 2004;38(1):42-5, abstract: "Forty one competitive athletes (22 male, 19 female) with persistent fatigue and/or recurrent infections associated with performance decrements had a thorough medical examination and a series of clinical investigations to identify potential medical causes." "Conditions with the potential to cause fatigue and/or recurrent infections were identified in 68% of the athletes. The most common were partial humoral immune deficiency (28%) and unresolved viral infections (27%). Non-fasting hypoglycaemia was common (28%). Other conditions included allergic disease (15%), new or poorly controlled asthma (13%), upper airway dysfunction (5%), sleep disorders (15%), iron depletion (3%), and one case of a thyroid disorder. A positive antinuclear antibody was detected in 21% of the athletes, without any clinical evidence of autoimmune disorders. Evidence of Epstein-Barr virus reactivation was detected in 22% of the athletes tested." Conclusions: "Athletes with recurrent infections, fatigue, and associated poor performance may benefit from a thorough investigation of potentially reversible underlying medical conditions, especially when these conditions cause disruption to training and competition."

[Note 14] Kreher JB, Schwartz JB, Sports Health 2012: "Symptoms of nonfunctional overreaching (NFO) and OTS are varied, nonspecific, anecdotal, and numerous" and "There have been no specific or sensitive levels defined for creatine kinase, urea, or iron."

[Note 15] The same: "Given the unethical nature of inducing OTS in athletes and uncertain pathogenesis, there are no evidence-based means of preventing OTS." Immediately after: "However, observation of training load, performance measures, and mood questionnaires can help interrupt the progression from FO to NFO/OTS. A study has shown a decrease in "burnout" in collegiate swimmers from 10% to zero when altering training load in response to the Profile of Mood States questionnaire. When the mood state decreased, training load was also decreased. Major components of prevention are screening and education. One should educate athletes at risk for overtraining that one of the initial signs of overreaching is increased rating of perceived exertion for a given workload." The treatment passage: "It is unclear which strategy is best" and "If stress, depression, and/or anxiety are increased with full rest, relative rest with well-defined expectations should be provided."

[Note 16] Labour Department, Introduction to the Heat Stress at Work Warning (document's own date 13 April 2026):

To make it easier for employers and employees to assess the level of heat stress when working outdoors or in an indoor environment without air conditioning in hot weather, the Labour Department has established, on the basis of the HKHI values published by the Observatory and the special "extreme hot weather" alert, a Heat Stress at Work Warning in three levels, amber, red and black, indicating the significant and increasing levels of heat stress employees face when working in such environments. / Once the Heat Stress at Work Warning is issued, the situation is updated hourly; and if a higher level of Heat Stress at Work Warning arises in the interval, the update is made earlier. / The relevant messages are shown on the home page of the Hong Kong Observatory's official website and on the MyObservatory mobile application. Employers and employees may also learn that a Heat Stress at Work Warning is in force by choosing to receive push messages from the MyObservatory or iAM Smart mobile applications. (our translation from the Chinese original)

Chinese original:

「為了讓僱主及僱員更容易評估在酷熱天氣下處於戶外或沒有設置空調系統的室內環境工作時的熱壓力水平，勞工處基於天文台發布的 HKHI 數值及「極端酷熱天氣」特別提示制定了工作暑熱警告，分為黃色、紅色及黑色三級，顯示僱員在有關環境工作時面對顯著及遞增的熱壓力水平。」「工作暑熱警告發出後會每小時更新情況，若果期間出現更高工作暑熱警告級別，則會提早作出更新。」「相關的訊息會在香港天文台官方網站首頁及「我的天文台」手機應用程式上顯示。僱主和僱員亦可透過選擇接收「我的天文台」或「智方便」手機應用程式的推送訊息而得知工作暑熱警告生效詳情。」

[Note 17] The same, the two footnotes on page 1:

§ The Labour Department issues the Heat Stress at Work Warning on the basis of the HKHI measured by the Observatory at King's Park. As the Observatory measures the HKHI at other locations, the Labour Department will also refer to the relevant data. If other HKHI monitoring stations show that heat stress in many parts of Hong Kong has reached a given level, the Labour Department will still issue the corresponding Heat Stress at Work Warning even though the index at the King's Park station has not reached that level. / # If the Observatory issues a special "extreme hot weather" alert, the Labour Department will issue an amber Heat Stress at Work Warning even where the Hong Kong Heat Index has not reached 30. (our translation from the Chinese original)

Chinese original:

「§ 勞工處基於天文台在京士柏量度的HKHI 為基礎發出工作暑熱警告。隨著天文台在其他地點量度HKHI，勞工處亦會參考相關數據。若其他HKHI 監測站顯示香港多處地點的熱壓力情況已達某個級別，即使京士柏站的指數未達到該水平，勞工處仍會發出對應的工作暑熱警告。」「# 若天文台發出「極端酷熱天氣」特別提示，即使香港暑熱指數未達30，勞工處亦會發出黃色工作暑熱警告。」

[Note 18] Hong Kong Observatory, explanation of the Hong Kong Heat Index:

The Hong Kong Heat Index is computed from the natural wet-bulb temperature (Tnw), the globe temperature (Tg) and the dry-bulb temperature (Ta), its value equalling 0.80Tnw + 0.05Tg + 0.15Ta. Generally speaking, when the index at King's Park is around 30 or above, the public should take appropriate precautions against the heat and avoid the health effects of hot weather. (our translation from the Chinese original)

Chinese original:

「香港暑熱指數是根據自然濕球溫度(Tnw)、黑球溫度(Tg)和乾球溫度(Ta)綜合計算出來，其數值相等於0.80Tnw + 0.05Tg + 0.15Ta。一般來說，當京士柏的指數在30左右或以上，市民便應採取適當的防暑措施，避免炎熱天氣帶來的健康影響。」

The Cold and Very Hot Weather Warnings page:

When Hong Kong is forecast to be generally affected by cold or very hot weather, the Observatory issues a warning calling on the public to be vigilant and to guard against hypothermia from the cold, or heat stroke and sunburn from the heat. (our translation from the Chinese original)

Chinese original:

「當預測香港普遍會受到寒冷或酷熱天氣影響時，天文台便會發出警告，呼籲市民提高警惕，預防因寒冷引起體溫過低，或因酷熱而中暑及曬傷。」

[Note 19] Hong Kong Observatory, Cold and Very Hot Weather Warnings page, the section on special weather tips for hot weather:

In some weather conditions, such as high temperature, high humidity or light winds, even though conditions have not reached the level for issuing a Very Hot Weather Warning, there is still a risk of heat stroke if the public do not take appropriate precautions. When the Observatory anticipates such conditions, it will issue special weather tips for hot weather through several channels, to remind the public early, to avoid the health effects of hot weather and to take full precautions against the heat. (our translation from the Chinese original)

Chinese original:

「在一些氣溫高、濕度高或風勢弱等的天氣情況下，雖然天氣條件未達發出酷熱天氣警告的水平，但如市民未有採取適當的預防措施，仍有中暑的風險。當天文台預計這種情況出現時，將透過多個渠道發放「炎熱天氣特別提示」，及早提醒市民，避免炎熱天氣影響健康及做足防暑措施。」

The precautions on very hot weather:

People engaged in outdoor activities should drink plenty of water and avoid over-exertion. Those feeling unwell should rest in a shaded area as soon as possible. Outdoor activities should as far as possible be arranged in the morning or later in the afternoon. In extreme hot weather, vigorous exercise should be avoided. / If symptoms such as dizziness, headache, nausea, shortness of breath and confusion appear, one should rest and seek help immediately, and seek medical attention as soon as possible. (our translation from the Chinese original)

Chinese original:

「在戶外活動的人士，應多補充水分和不要過度勞累。於感覺不適時，應儘快到陰涼的地方休息。戶外活動儘可能安排在早上或下午較後的時間進行。在極端酷熱天氣下，應避免劇烈運動。」 「若出現頭暈、頭痛、噁心、氣促及神志不清等徵狀，應立刻休息和求助，並儘快求醫。」

[Note 20] Labour Department, Guidance Notes on Prevention of Heat Stroke at Work (third edition, April 2026), section 6.1, reproduced in full:

Some symptoms indicating that an employee may be developing a heat illness include: • fatigue • dizziness, headache • thirst • nausea, vomiting • rising body temperature • rapid breathing, difficulty breathing • palpitations, a rapid and weak pulse • localised muscle cramps and pain (especially in the feet and abdomen), which in severe cases may become generalised cramps • *clammy skin, profuse sweating and pallor (common in heat exhaustion) • *dry, flushed, hot skin with no sweating (common in heat stroke) • confusion or even unconsciousness (our translation from the Chinese original)

Chinese original:

「一些顯示僱員可能出現熱疾病的徵狀包括：• 疲倦 • 頭暈、頭痛 • 口渴 • 噁心、嘔吐 • 體温上升 • 呼吸急促、呼吸困難 • 心悸、脈搏急促而微弱 • 局部肌肉痙攣、疼痛（尤見於足部及腹部），嚴重的可能出現全身痙攣 • *皮膚濕冷、大量出汗及面色蒼白（常見於熱衰竭） • *皮膚乾燥、潮紅、發熱及無汗（常見於中暑） • 神志不清甚至昏迷」

The asterisked footnote in full:

* The symptoms of heat illness vary from person to person, and whether the affected employee is sweating profusely or not sweating should not on its own be used as the criterion for deciding whether heat stroke has occurred and whether first aid should be given. Generally speaking, an employee working long hours in a hot environment or carrying out heavy physical activity has a chance of heat stroke; when the relevant symptoms above appear, help should be sought as soon as possible and the affected employee cooled down, with appropriate first aid given according to the employee's actual condition. (our translation from the Chinese original)

Chinese original:

「* 熱疾病的徵狀因人而異，不應單憑病患員工是否大量出汗或無汗作為斷定中暑及決定應否施行急救處理的準則。一般而言，如僱員長時間在酷熱環境下工作或進行大量體力活動，便有機會中暑，若出現上述相關的徵狀時，應儘快尋求協助及讓不適的員工降溫，並根據員工的實際情況，作出適當的急救處理。」

[Note 21] The same, section 6.2:

Heat stroke can appear and worsen rapidly, so initial first aid must be given to the affected employee, and the first task is to lower their body temperature until the condition improves or ambulance personnel arrive. (our translation from the Chinese original)

Chinese original:

「中暑可以迅速出現並惡化，所以必須對病患員工施行初步急救，而首要任務就是為他降低身體的溫度，直至情況好轉或救護人員到達。」

The methods listed are:

Spray them with water, then use a fan or electric fan to help the water evaporate and lower the body temperature / Wipe them continuously with a sponge or towel soaked in cold water to cool them / Placing sponges or towels soaked in cold water in both armpits and the groin helps cooling / On no account give a drink / The affected employee's response to cooling must be watched continuously; if shivering appears, cooling must be stopped immediately and the employee covered to keep warm / Send them to hospital as quickly as possible (our translation from the Chinese original)

Chinese original:

「向其灑水，再用扇或電風扇協助揮發水分，降低體溫」 「用濕有冷水的海綿／毛巾持續抹身降溫」 「在兩邊腋下及腹股溝放置濕有冷水的海綿／毛巾有助降溫」 「切勿給予飲料」 「要持續注意病患員工對降溫的反應，若出現震顫，應立即停止降溫並遮蓋員工身體以作保暖」 「儘速送院」

[Note 22] The same, section 4.1.2:

Generally speaking, to relieve employees' heat stress, employers should provide employees with about 250 to 500 millilitres of cool drinking water an hour. The higher the heat stress on employees at work, the more water the body loses through sweating, so employers must increase the supply of drinking water to employees according to the circumstances, and it is recommended that they drink about 250 millilitres of cool drinking water every 15 to 20 minutes, that is about 750 to 1,000 millilitres of cool drinking water an hour (but they should not drink more than 1,500 millilitres of water an hour, so as not to lower the salt concentration in the blood below the normal level). (our translation from the Chinese original)

Chinese original:

「一般而言，為紓緩僱員的熱壓力，僱主應向員工提供每小時約250至500毫升清涼飲用水。僱員在工作時的熱壓力越高，身體因出汗而流失的水分便越多，僱主須因應情況給員工增加飲用水的供應，建議讓他們每15至20分鐘飲用約250毫升清涼飲用水，即每小時飲用約750至1,000毫升的清涼飲用水（但不應每小時飲用超過1,500毫升的水，以免導致血液中的鹽分濃度低於正常水平）。」

Two further sentences, the second of which the source introduces as applying to employees who have to work in a hot environment for more than two hours:

Drinking only when thirsty increases the risk of heat stroke, because by then the body may already be dehydrated / employers may also consider providing drinks containing electrolytes (such as sodium and potassium) (our translation from the Chinese original)

Chinese original:

「如果感到口渴時才喝水，會增加中暑風險，因其時身體可能已經出現脫水情況」 「亦可考慮提供含有電解質（如：鈉質、鉀質）的飲料」

[Note 23] Reynolds CJ, Cleaver BJ, Finlay SE, BMJ Case Rep 2012;2012:bcr0820114625, abstract: "The patient reported sweating excessively while performing 90 min of strenuous exertion in a humidified room heated to an ambient temperature of 40.6°C. After the workout she drank 3.5 litres of water before experiencing breathlessness, severe muscle cramps, nausea and general malaise. Initial investigations revealed severe hyponatraemia (120 mmol/l). … This case highlights the dangers of overzealous fluid replacement following severe exertion in a hot environment."

[Note 24] healthdirect Australia, "Rhabdomyolysis" (Last reviewed: June 2025): "Symptoms of rhabdomyolysis may not start for hours or days after your muscle injury." Under the heading "When should I call an ambulance or go to the emergency department?": "Seek medical attention urgently if you have symptoms of rhabdomyolysis — muscle pain, muscle swelling, muscle weakness and dark urine." The symptom list: "The symptoms of rhabdomyolysis will depend on the cause, but include: muscle pain or swelling / muscle weakness / fatigue (tiredness) / dark red to brown urine (wee) / fever" Two further sentences: "It's important to get treatment early to avoid life threatening complications." "Early diagnosis and treatment of rhabdomyolysis increases your chances of a full recovery."

[Note 25] Tietze DC, Borchers J, Sports Health 2014: "For an athlete with severe symptoms (CK greater than 5 times the upper limit of normal or darkening of the urine), hospital admission is indicated for intravenous hydration with normal saline (1-2 L/h) maintaining a urine output of 200 mL/h." One of the low-risk conditions at the 72-hour gate of the CHAMP return protocol is "UA is negative"; another passage of the same paper, citing another work, describes a low-risk athlete as one where "the urine is clear"; and "There are no evidence-based guidelines for return to play after an episode of ER."

[Note 26] Lauersen JB, Bertelsen DM, Andersen LB, Br J Sports Med 2014;48(11):871-7: "Stratified exposure analyses proved no beneficial effect for stretching (RR 0.963 (0.846-1.095)), whereas studies with multiple exposures (RR 0.655 (0.520-0.826)), proprioception training (RR 0.550 (0.347-0.869)), and strength training (RR 0.315 (0.207-0.480)) showed a tendency towards increasing effect. Both acute injuries (RR 0.647 (0.502-0.836)) and overuse injuries (RR 0.527 (0.373-0.746)) could be reduced by physical activity programmes." and "Strength training reduced sports injuries to less than 1/3 and overuse injuries could be almost halved."

[Note 27] healthdirect Australia, all four sentences of the section on whether rhabdomyolysis can be prevented: "You can prevent exercise-induced rhabdomyolysis by slowly building up resistance training." "You can lower your chance of developing rhabdomyolysis by staying hydrated." "Talk with your doctor or pharmacist about any medicines you take that may increase your chance of developing rhabdomyolysis." "You can't prevent all causes of rhabdomyolysis, such as when it's caused by an underlying health condition or an accident."

[Note 28] Buist I et al., BMC Musculoskelet Disord 2007;8:24: "To minimize the risk of a RRI, an increase of training duration or intensity by no more than 10% is recommended, i.e. the 10% rule. However, so far no studies have examined the effect…"

[Note 29] Buist I et al., Am J Sports Med 2008;36(1):33-9, abstract: "The graded training program was not preventive for sustaining an RRI (chi(2) = 0.016, df = 1, P = .90). The incidence of RRI was 20.8% in the graded training program group and 20.3% in the standard training program group." That programme "was based on the 10% training rule".

[Note 30] Kreher & Schwartz, table 5, "Preventative measures for nonfunctional overreaching/overtraining syndrome", all twelve items in the original: "Periodization of training / Tapering for competition / Adjust training volume and intensity based on performance and mood / Ensure adequate calories for training load / Ensure adequate hydration / Ensure adequate carbohydrate ingestion during exercise / Ensure adequate sleep / Promoting mental toughness or resilience as buffer / Abstinence of training following infection, heat stroke/stress, periods of high stress / Avoid extreme environmental conditions / Utilize Profile of Mood States (or stress level) and alter training load / Rest period of greater than 6 hours between exercise bouts"

[Note 31] Labour Department, Guidance Notes on Prevention of Heat Stroke at Work, sections 4.6.2 to 4.6.4:

4.6.2 Where an employee has never worked, or has not worked for more than a month, in a hot environment, the employer should arrange a heat acclimatisation period of at least 5 days, so that the employee can fully acclimatise to working in a hot environment. On the first day, the employee's work in the hot environment should not exceed 20% of normal working hours, with a further 20% of normal working hours added each day thereafter, until the employee is fully acclimatised and works in the hot environment as usual. / 4.6.3 Where an employee has been away from work in a hot environment for two weeks to a month, on their return the employer should also arrange a heat acclimatisation period of at least 4 days, so that they can re-acclimatise to work in a hot environment. On the first day back, the employee's time working in the hot environment should not exceed 50% of normal working hours; thereafter a further 20% of normal working hours may be added each day, gradually returning to the normal working time in the hot environment. / 4.6.4 Past research has shown that more than half of fatal heat stroke accidents involved employees not acclimatised to working in a hot environment, with the accidents occurring during their first few days at work. Employers should therefore pay particular attention to the heat stress risk faced at work by employees who have not completed acclimatisation, and ensure that adequate control measures have been taken. (our translation from the Chinese original)

Chinese original:

「4.6.2 若僱員從未曾或者已經超過一個月沒有在酷熱環境工作，僱主應安排最少5天的熱適應期，讓員工可以完全地適應在酷熱環境中工作。員工首天在酷熱環境中工作不應超過正常工作時間的20%，之後每天再增加正常工作時間的20%，直至員工完全適應並如常在酷熱環境工作。」「4.6.3 若員工已有兩星期至一個月的時間沒有在酷熱環境中工作，當他們復工時，僱主亦應安排最少4天的熱適應期，讓他們可以重新適應在酷熱環境中的工作。在復工的首天，員工在酷熱環境工作的時間不應超過正常工作時間的50%；之後每天可再增加正常工作時間的20%，逐步回復到正常在酷熱環境工作的時間。」「4.6.4 以往有研究顯示超過一半的中暑致命意外涉及未適應在酷熱環境工作的員工，令意外在他們首幾天的工作期間發生。因此，僱主應特別留意未完成熱適應的員工工作時的熱壓力風險，確保已採取足夠的控制措施。」

[Note 32] Rawson ES et al., Sports Med 2017, abstract: "Creatine monohydrate does not appear to be a precipitating factor for exertional rhabdomyolysis." and "both of which would predict a lower risk of rhabdomyolysis, not a higher risk", "a myth was born".

[Note 33] Antonio J et al., J Int Soc Sports Nutr 2021;18(1):13: "one must exercise caution when using blood creatinine and estimated creatinine clearance/glomerular filtration rate in individuals who consume high meat intake or supplement with creatine"

[Note 34] Pharmacy and Poisons Regulations (Chapter 138A), Part 1 of the Poisons List in Schedule 10:

Androgenic, oestrogenic and progestogenic substances as follows — steroid compounds with androgenic or oestrogenic or progestogenic activity; their esters; save where contained in an oral preparation intended for contraceptive use only, that preparation containing per dose not more than the following quantities of the substance — (our translation from the Chinese original)

Chinese original:

「雄激素、雌激素與孕激素物質如下 —— 具有雄激素或雌激素或孕激素作用的類固醇化合物；它們的酯類；但如包含在擬只作避孕用的某口服製劑內，而該製劑每劑含有不多於以下分量的物質，則屬例外 ——」

The heading of Schedule 3:

Regulation 9: Substances that may be sold by retail only in accordance with a prescription given by a registered medical practitioner, registered dentist or registered veterinary surgeon (our translation from the Chinese original)

Chinese original:

「第9條 規定僅可按照註冊醫生、註冊牙醫或註冊獸醫開出的處方而以零售方式銷售的物質」

[Note 35] Pharmacy and Poisons Ordinance (Chapter 138), section 23, headed as prohibiting possession of Part 1 poisons, both subsections in full:

(1) Except in accordance with the provisions of this Ordinance, no person shall possess any poison listed in Part 1 of the Poisons List, and the burden of proving that possession of the poison concerned was in accordance with the provisions of this Ordinance lies on the person concerned. / (2) Where any poison listed in Part 1 of the Poisons List was obtained in the circumstances listed in section 28(1)(a), (b), (c) or (d), this Ordinance does not prohibit any person from possessing that poison. (our translation from the Chinese original)

Chinese original:

「(1) 除按照本條例條文的規定外，任何人不得管有毒藥表第1部所列任何毒藥，而有關的人須就管有有關毒藥乃按照本條例條文的規定一事負責舉證。」「(2) 凡毒藥表第1部所列任何毒藥是在第 28(1)(a)、(b)、(c)或(d)條所列情況下取得的，本條例不禁止任何人管有該等毒藥。」

The circumstances listed in section 28(1), headed as exemptions in respect of medicines, include:

medicines supplied by a registered medical practitioner for the purposes of medical treatment, by a registered dentist for the purposes of dental treatment, or by a registered veterinary surgeon for the purposes of animal treatment / medicines dispensed by an authorised seller of poisons on premises duly registered under this Ordinance (our translation from the Chinese original)

Chinese original:

「註冊醫生為提供醫療、註冊牙醫為提供牙科治療，或註冊獸醫為提供動物治療而供應的藥物」 「獲授權毒藥銷售商在根據本條例妥為註冊的處所內配發的藥物」

Section 34:

Any person who commits any offence under this Ordinance is, unless a penalty is expressly provided otherwise, liable on conviction to a fine at level 6 and to imprisonment for 2 years. (our translation from the Chinese original)

Chinese original:

「任何人犯本條例所訂的任何罪行，除非另有明文規定的罰則，否則一經定罪，可處第6級罰款及監禁2年。」

Schedule 8 to the Criminal Procedure Ordinance (Chapter 221):

level 6 $100,000 (our translation from the Chinese original)

Chinese original:

「第6級 $100,000」

[Note 36] Drug Office of the Department of Health, listing of products found to contain undeclared Western medicines, entry of 23 October 2017, the body text of the Chinese page:

In Hong Kong, the above products are not registered pharmaceutical products. (our translation from the Chinese original)

Chinese original:

「在香港，上述產品並非註冊藥劑製品。」

The English version on GW501516: "was found to cause cancers in mice and rats during animal safety studies"

#What this article does not state

• How many cases of rhabdomyolysis Hong Kong has — no statement is made. In the PubMed index, the only rhabdomyolysis case literature involving Hong Kong is one tarantula bite case (Hong Kong) and a crayfish-related case (authors from the University of Hong Kong and its Shenzhen hospital, with the case occurring in Shenzhen); the Hospital Authority's statistical report publishes total accident and emergency attendances without breakdown by cause or diagnosis, so rhabdomyolysis cannot be counted from it. The scope of this conclusion is limited to those two classes of source (literature indexed in PubMed, and the Hospital Authority's statistical report) and does not cover other Hong Kong government publications. So all that can be said is that there is no citable Hong Kong figure, not that Hong Kong has no such cases.
• This article reproduces no self-assessment table for overtraining or REDs. The tool introduced by the International Olympic Committee's 2023 consensus statement is named the REDs Clinical Assessment Tool-Version 2, and the abstract itself states that it assists in clinical detection and diagnosis; the full tool is not published with that abstract. For the same reason this article does not reproduce table 2 of Kreher and Schwartz's symptom comparison, nor the US military's CHAMP staged return-to-training protocol (every gate of which requires CK and urinalysis results the reader does not have).
• This article does not reproduce the red flag list from the Primary Healthcare Commission's clinical guideline for first-contact physiotherapists, but the document was found, and this article states where it is, what it is and who it is for. Its full title is Clinical Guideline for First-contact Physiotherapists on Assessment and Cross-disciplinary Management Approach for Common Musculoskeletal Problems in Primary Care Setting, issued by the Primary Healthcare Commission, self-dated "First published: Dec 2025", 55 pages, carried on the Health Bureau's website at healthbureau.gov.hk/phcc/. Language status: English; the Primary Healthcare Commission's Chinese page for discipline-based guidelines states itself that the English version should be consulted, so this article cites the English and gives a rendering. Its table 3.1 is headed "Common Red Flag Conditions in Primary Care Setting that Require Urgent or Early Medical Care", in three tiers. This article does not reproduce that table, for the same reason as the REDs tool: most of its items require blood pressure, pulse, respiratory rate and a clinical examination to judge, and a reader at home who cannot match them will use it to conclude "I am not on the table, so I need not go" — which is precisely the direction of inference this whole article exists to avoid. That guideline is written for first-contact physiotherapists who have completed recognised training, not for patients.
• This article makes no statement about whether Hong Kong has a statutory registration system for private fitness trainers. A common claim is that Hong Kong has no mandatory registration system for private trainers. The page on a Hong Kong government website closest to that question is the Leisure and Cultural Services Department's page on recognised qualifications for fitness rooms (page's own revision date 29 January 2026); and what it sets is that a person who has completed one of the listed courses may apply to register as a user of a Leisure and Cultural Services Department fitness room — that is, eligibility to register as a user, not the regulation of private trainers' practice, and the page nowhere mentions the private market. In other words, that page cannot answer the question; and whether Hong Kong has a statutory registration system at all is a question that can only be answered by examining the legislation. This article therefore makes no statement. An untested "there is none" is as serious as a wrong number, because the reader has no way to verify something that does not exist.
• This article makes no statement about whether people over 40 should have an exercise electrocardiogram before starting vigorous exercise. Pre-participation cardiovascular screening guidelines fall outside the subject matter of every source cited here — the literature cited concerns rhabdomyolysis, overtraining and heat, and none of it addresses pre-exercise cardiovascular assessment. For the same reason, this article has not written any list of "stop immediately if the following happens during training" — a safety list may only be copied from a sourced version, never added to.
• The room temperature range for hot yoga, the fluid lost per class, and any "detox" effect — no statement is made on any of them. The only sourced temperature found here is the 40.6°C of a single case report; no controlled study provides an injury rate or a figure for fluid lost in hot yoga; and on the widely circulated claims of 1–2 litres lost per class and of detoxification through heat, the only hot yoga document cited here (Reynolds et al. 2012) is a single case report that did not measure fluid loss and does not discuss detoxification.
• Protein intake, protein intake for people with kidney disease, DHEA, Tribulus and the like — no statement is made; see the supplements article. The protein figures in circulation (1.6–2.2 g/kg, 1.5–2 g/kg) differ from one another and from the 1.4–2.0 g/kg/day of the International Society of Sports Nutrition's 2017 position stand; and the claim that above 3 g/kg has adverse effects on bone health points the opposite way to that position stand (which, on more than 3.0 g/kg/day, writes that it may have positive effects on body composition and says nothing about bone). None of the three figures is cited here.
• Where this article cites MedlinePlus it restates rather than quotes, for reasons of copyright. The copyright notice at the foot of that page reads: "Any duplication or distribution of the information contained herein is strictly prohibited." Language status: that encyclopedia entry has an English version and a Spanish version (medlineplus.gov/spanish/ency/article/000473.htm); the "Chinese, Traditional (Cantonese dialect)" page under the MedlinePlus language index carries no rhabdomyolysis entry, while under the same heading Kidney has 6 items and Exercise has 23 — that is, the heading itself has content. So there are English and Spanish versions and no Chinese one. Even so, the copyright notice alone is enough for this article to restate only.
• The Labour Department's figures for drinking water, rest periods and heat acclimatisation schedules are all occupational safety figures written for employers and employees, not prescriptions for recreational exercise. The Heat Stress at Work Warning likewise addresses only employees working outdoors or in indoor environments without air conditioning; the Labour Department has made no recommendation for fitness training or recreational sport, and this article has not made one on its behalf.
• This article does not equate the Observatory's special weather tips for hot weather with the special "extreme hot weather" alert mentioned in the Labour Department's document. The definition of the Observatory's special weather tips for hot weather is printed on its Cold and Very Hot Weather Warnings page (reproduced above), and that definition itself supports keeping them apart: by its own terms the Observatory's special weather tips for hot weather are issued when conditions have not reached the level of a Very Hot Weather Warning, while the Labour Department's document refers to a special "extreme hot weather" alert — the two names point in opposite directions of heat. There is no standalone page on the Observatory's website defining a product by the name of the special "extreme hot weather" alert, so whether the two are the same product remains unconfirmed and this article does not equate them.
• The Centre for Health Protection's Chinese health topic pages insert typesetting spaces between characters (for example 「定 期 進 行 體 能 活 動」); what is quoted above is the same sentence with those typesetting spaces removed, with the wording unchanged from that page.
• Hong Kong does have published times to care, but they are written for clinicians rather than for members of the public to use at home. Table 3.1 of the Primary Healthcare Commission's first-contact physiotherapy guideline above sets three tiers, in the English original: "Urgent - Priority cat 1: Refer to A&E service within same day", "Urgent - Priority cat 2: Refer to FD/MD within 1-2 days" and "Early: Refer to FD/MD within 2 weeks" — that is, Category 1 urgent, same-day referral to accident and emergency; Category 2 urgent, referral to a family doctor or medical officer within 1 to 2 days; and early, referral to a family doctor or medical officer within two weeks. But those three tiers are referral times applied by a first-contact physiotherapist who has already taken a history, examined the patient and measured their vital signs; they are not a table for a reader to look up hours against symptoms. So what can be said is: among the Hong Kong government pages and documents examined for this article, not one publishes a triage timetable for members of the public to use at home (of the form "with this symptom, see a doctor within X hours"); and the only source cited here that speaks to the public directly about urgency is Australia's healthdirect, whose word is "urgently", with no number of hours.

#Sources

• Centre for Health Protection, Department of Health, Report of Unintentional Injury Survey 2018 (the definition of a sports injury; the 0.8% population proportion and its breakdown by sex and age; 17.5% of all injury events; table 3.13's fitness training at 2.3, in thousands, of events = 4.1% and the shares of the other activities; table 3.15's overexertion at 51.8%; the ICECI definition of overexertion): https://www.chp.gov.hk/files/pdf/report_of_unintentional_injury_survey_2018_tc.pdf and English version https://www.chp.gov.hk/files/pdf/report_of_unintentional_injury_survey_2018_en.pdf (the PDF's own revision date 2 September 2021; fieldwork 17 September 2018 to 14 July 2019; retrieved 2 August 2026)
• Centre for Health Protection, Department of Health, Physical Activity (quoting the World Health Organization's recommendations for adults, including muscle-strengthening activity on two days or more a week; the Behavioural Risk Factor Survey of 2023 at 14.8%, 16.0% and 13.4%): https://www.chp.gov.hk/tc/healthtopics/content/100200/8804.html and English version https://www.chp.gov.hk/en/healthtopics/content/100200/8804.html (page's own date 15 April 2025; retrieved 2 August 2026)
• Hospital Authority, Fees and Charges (400 dollars per accident and emergency attendance and the Category I and II exemption; 2,100 dollars for non-eligible persons; 300 dollars a day for an acute bed; the annual charge cap of ten thousand dollars): https://www.ha.org.hk/visitor/ha_view_content.asp?Content_ID=10045&Lang=CHIB5&Dimension=100&Ver=HTML and the English version at the same address with Lang=ENG (the page states an effective date of 1 January 2026; retrieved 2 August 2026)
• Hospital Authority, Accident and Emergency Services (eighteen public hospitals; the names of the five triage categories; the service targets for Categories I to III; the 350 dollar refund on leaving after triage): https://www.ha.org.hk/visitor/ha_view_content.asp?Content_ID=10051&Lang=CHIB5&Dimension=100&Ver=HTML and the English version at the same address with Lang=ENG (retrieved 2 August 2026)
• Labour Department, Introduction to the Heat Stress at Work Warning (the three HKHI thresholds of 30, 32 and 34 and the explanation of each level; hourly updating and earlier updating on escalation; the MyObservatory and iAM Smart pushes; the § footnote under the table on the King's Park basis and the other monitoring stations; the # footnote's exception for the special "extreme hot weather" alert; the warning's scope being confined to outdoor or unair-conditioned indoor working environments): https://www.labour.gov.hk/common/public/oh/HSWW_tc.pdf and English version https://www.labour.gov.hk/common/public/oh/HSWW_en.pdf (document's own date 13 April 2026; retrieved 2 August 2026)
• Labour Department, Guidance Notes on Prevention of Heat Stroke at Work, third edition (section 4.1.2 on drinking water and the 1,500 millilitre ceiling; section 4.1.4 on thirst as a late signal; section 4.1.5 on electrolytes; sections 4.6.2, 4.6.3 and 4.6.4 on the heat acclimatisation schedule, all three reproduced; section 6.1's complete list of heat illness symptoms and the full asterisked footnote (the rule against judging by sweating or its absence, together with its second half on seeking help and cooling down); section 6.2 on the order of first aid, stopping at shivering, and sending to hospital as quickly as possible): https://www.labour.gov.hk/common/public/oh/Heat_Stress_GN_tc.pdf and English version https://www.labour.gov.hk/common/public/oh/Heat_Stress_GN_en.pdf (document's own edition: third edition, April 2026; retrieved 2 August 2026)
• Hong Kong Observatory, Cold and Very Hot Weather Warnings (the Very Hot Weather Warning publishing no numerical threshold; the precautions in full, including the sentence on resting and seeking help immediately and seeking medical attention as soon as possible when dizziness, headache, nausea, shortness of breath or confusion appear, and the sentence on avoiding vigorous exercise in extreme hot weather; the full definition in the section on special weather tips for hot weather): https://www.hko.gov.hk/tc/wservice/warning/coldhot.htm and English version https://www.hko.gov.hk/en/wservice/warning/coldhot.htm (the page itself carries no revision date; retrieved 3 August 2026)
• Hong Kong Observatory, Regional Weather Information Platform, explanation of the Hong Kong Heat Index (the HKHI formula; the public taking precautions at a King's Park index around 30 or above): https://www.hko.gov.hk/tc/wxinfo/awsgis/regional_portal.html?ele=hkhi and English version https://www.hko.gov.hk/en/wxinfo/awsgis/regional_portal.html?ele=hkhi (page's own revision date 9 July 2026; retrieved 3 August 2026)
• Pharmacy and Poisons Regulations (Chapter 138A), Part 1 of the Poisons List in Schedule 10 and Schedule 3 (the entry on steroid compounds with androgenic, oestrogenic or progestogenic activity; the restriction to sale on prescription), the Chinese and English provisions taken from the Department of Justice's compilation of the laws: https://resource.data.one.gov.hk/doj/data/hkel_c_leg_cap_1_cap_300_zh-Hant.zip (consolidated version dated 3 July 2026; retrieved 2 August 2026)
• Pharmacy and Poisons Ordinance (Chapter 138), both subsections of section 23 in full (subsection (1) prohibiting possession and placing the burden of proof; subsection (2) not prohibiting possession in the circumstances of section 28(1)(a)–(d)), paragraphs (a) and (c) of section 28(1) headed as exemptions in respect of medicines, and section 34 (a fine at level 6 and imprisonment for 2 years), from the same compilation (consolidated version dated 14 May 2026; retrieved 2 August 2026)
• Criminal Procedure Ordinance (Chapter 221), Schedule 8 (a level 6 fine of $100,000), from the same compilation (retrieved 2 August 2026)
• Drug Office of the Department of Health, listing of products found to contain undeclared Western medicines, entry of 23 October 2017 ("In Hong Kong, the above products are not registered pharmaceutical products."; the three SARMs products; GW501516 causing cancer in animals and the World Anti-Doping Agency alert of 2013): https://www.drugoffice.gov.hk/eps/news/showNews/Singapore%3A+HSA+Alert%3A+Bodybuilding+products+sold+online+contain+harmful+substances/consumer/2017-10-23/tc/29232.html and the English version at the same path with /en/ (entry date 23 October 2017; retrieved 2 August 2026)
• healthdirect Australia, Rhabdomyolysis (the "Seek medical attention urgently…" banner; the symptom list; the classification of causes; complications; treatment; all four sentences of the section on whether rhabdomyolysis can be prevented, including "You can't prevent all causes of rhabdomyolysis"): https://www.healthdirect.gov.au/rhabdomyolysis (the page's own Last reviewed June 2025; retrieved 2 August 2026)
• Rout P, Chippa V, Adigun R. Rhabdomyolysis. StatPearls, NCBI Bookshelf NBK448168 (no established diagnostic CK level and the 3–5 times and 5 times formulations; a normal range of 20–200 U/L; the triad in fewer than half of patients; dark urine at 30–40% against 50% on the same page; the non-specific and systemic features; the list of complications; a mortality rate of 30–50% in hospitalised patients with acute kidney injury; statins as the most common pharmaceutical cause; the goal of management; the sentence "A high index of suspicion is sometimes necessary" following the triad passage in History and Physical): https://www.ncbi.nlm.nih.gov/books/NBK448168/ (the page's own Last Update July 7, 2025; PMID 28846335; retrieved 2 August 2026)
• Tietze DC, Borchers J. Exertional rhabdomyolysis in the athlete: a clinical review. Sports Health 2014;6(4):336-9 (urinary myoglobin as a less sensitive indicator not to be used as the sole objective diagnostic marker; an incidence of 29.9 per 100,000 patient years; the diagnosis to be made in association with the clinical syndrome; the admission threshold; the CHAMP return protocol; "no evidence-based guidelines for return to play") (DOI 10.1177/1941738114523544; PMID 24982707; PMCID PMC4065559)
• Rawson ES, Clarkson PM, Tarnopolsky MA. Perspectives on Exertional Rhabdomyolysis. Sports Med 2017;47(Suppl 1):33-49 (the list of risk factors; the eccentric contraction and "negatives" mechanism; the passage on dehydration; statins at 0.1%; NSAIDs reducing renal perfusion; myoglobinuria without rhabdomyolysis in ultra-marathon runners; no visible myoglobinuria in the eccentric experiment; the physical education case of 119 students and the case of the 12-year-old boy; 40% acute kidney injury in the marathon runners and the 19 Comrades cases; creatine not a precipitating factor; four of the six men in the case series ingesting ephedrine) (DOI 10.1007/s40279-017-0689-z; PMID 28332112; PMCID PMC5371628)
• Kreher JB, Schwartz JB. Overtraining syndrome: a practical guide. Sports Health 2012;4(2):128-38 (the European College of Sport Science three-tier definition table; NFO and OTS distinguishable only after rest; "OTS cannot be diagnosed" and "only in retrospect"; the 14–21 day line; a cause found in 68%; the list of organic diseases; no specific or sensitive levels for CK, urea or iron; symptoms "varied, nonspecific, anecdotal, and numerous"; the sentence that there are no evidence-based means of prevention and the However passage that follows, including collegiate swimmers' burnout falling from 10% to zero; all twelve items of table 5 on preventative measures; the treatment sentence "If stress, depression, and/or anxiety are increased with full rest, relative rest with well-defined expectations should be provided."; and the sentence on rating of perceived exertion following "Major components of prevention are screening and education") (DOI 10.1177/1941738111434406; PMID 23016079; PMCID PMC3435910)
• Meeusen R, et al. (joint consensus statement of the European College of Sport Science and the American College of Sports Medicine) Prevention, diagnosis, and treatment of the overtraining syndrome. Med Sci Sports Exerc 2013;45(1):186-205 (NFO and OTS being hard to distinguish; "no scientific evidence to either confirm or refute"; markers of which "none of them meet all the criteria to make their use generally accepted". The abstract is what is cited) (DOI 10.1249/MSS.0b013e318279a10a; PMID 23247672)
• Mountjoy M, et al. 2023 IOC consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med 2023;57(17):1073-1097 (the definition of low energy availability; the REDs Clinical Assessment Tool-Version 2 as a clinical tool. The abstract is what is cited) (DOI 10.1136/bjsports-2023-106994; PMID 37752011)
• Yow LPS, Ho HY, Lum IYW, Hanif IM. Exercise-Induced Rhabdomyolysis: A Case Series of Spin-Related Rhabdomyolysis. Cureus 2021;13(7):e16352 (the triad appearing within a week of the first spin class) (DOI 10.7759/cureus.16352; PMID 34277311)
• Ramme AJ, et al. Exertional rhabdomyolysis after spinning: case series and review of the literature. J Sports Med Phys Fitness 2016;56(6):789-93 (three cases in deconditioned individuals; complications in severe cases) (PMID 25665750)
• Reynolds CJ, Cleaver BJ, Finlay SE. Exercise associated hyponatraemia leading to tonic-clonic seizure. BMJ Case Rep 2012;2012:bcr0820114625 (Bikram yoga at 40.6°C, 3.5 litres of water, a blood sodium of 120 mmol/l, a seizure and intensive care) (DOI 10.1136/bcr.08.2012.4625; PMID 22927272)
• Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries. Br J Sports Med 2014;48(11):871-7 (25 trials, 26,610 people, 3,464 injuries; stretching RR 0.963; proprioception 0.550; strength training 0.315; acute 0.647 and overuse 0.527) (DOI 10.1136/bjsports-2013-092538; PMID 24100287)
• Wang H, Wang L, Pan Y. Impact of different doses of cold water immersion … a network meta-analysis. Front Physiol 2025;16:1525726 (55 randomised controlled trials; the 10–15 minute 11–15°C group at SMD −1.45; the 5–10°C group at −1.12; the authors' own reservation): https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2025.1525726/full (published 26 February 2025; retrieved 2 August 2026)
• Petersen AC, Fyfe JJ. Post-exercise Cold Water Immersion Effects on Physiological Adaptations to Resistance Training… Front Sports Act Living 2021;3:660291 (cold water immersion attenuating resistance training adaptations; the authors' own "evidence is limited"; a narrative review) (DOI 10.3389/fspor.2021.660291; PMID 33898988)
• Wiewelhove T, et al. A Meta-Analysis of the Effects of Foam Rolling on Performance and Recovery. Front Physiol 2019;10:376 (21 studies; pre-rolling sprint +0.7% and flexibility +4.0%; post-rolling pain perception +6.0%; overall "rather minor and partly negligible") (DOI 10.3389/fphys.2019.00376; PMID 31024339; PMCID PMC6465761)
• Leabeater AJ, et al. Under the Gun: Percussive Massage Therapy and Physical and Perceptual Recovery in Active Adults. J Athl Train 2024;59(3):310-316 (65 people with contralateral limb control; no significant interaction; a slight increase in soreness perception at d=−0.35 and −0.48) (DOI 10.4085/1062-6050-0041.23; PMID 37248364)
• Antonio J, et al. Common questions and misconceptions about creatine supplementation. J Int Soc Sports Nutr 2021;18(1):13 (caution in interpreting creatinine; the 12, 8 and 2 distribution in the Persky and Rawson review; the declared relationship between the authors and the creatine industry) (DOI 10.1186/s12970-021-00412-w; PMID 33557850; PMCID PMC7871530)
• Jäger R, et al. ISSN Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20 (1.4–2.0 g/kg/day; the direction of the research on more than 3.0 g/kg/day. Cited here only to show the divergence among the figures in circulation, and not cited in the body as a recommendation) (DOI 10.1186/s12970-017-0177-8; PMID 28642676)
• MedlinePlus Medical Encyclopedia, Rhabdomyolysis (the symptom and cause lists, including the muscle tenderness, joint pain, seizures and unintentional weight gain added to the combined list here; the section on when to contact a medical professional consisting of one sentence with no stratification by time; the prevention sentence on removing excess clothing and immersing the body in cold water in heat stroke. That page's copyright notice reads "Any duplication or distribution of the information contained herein is strictly prohibited.", so this article restates only; language status: English plus Spanish, with no Chinese version, established on the MedlinePlus language index's "Chinese, Traditional (Cantonese dialect)" page using Kidney at 6 and Exercise at 23 as controls): https://medlineplus.gov/ency/article/000473.htm (page's own review date 2 September 2025; retrieved 2 August 2026)
• This site: the article on the evidence for supplements / the article on low back pain / the article on reading laboratory and imaging reports
• Buist I, Bredeweg SW, Lemmink KAPM, Pepping GJ, Zwerver J, van Mechelen W, Diercks RL. The GRONORUN study: is a graded training program for novice runners effective in preventing running related injuries? Design of a Randomized Controlled Trial. BMC Musculoskelet Disord 2007;8:24 (the naming of "the ten percent training rule"; "To minimize the risk of a RRI, an increase of training duration or intensity by no more than 10% is recommended, i.e. the 10% rule. However, so far no studies have examined the effect…"; the intervention being an increase of 10% a week in running time) (DOI 10.1186/1471-2474-8-24; PMID 17331264; PMCID PMC1821023)
• Buist I, Bredeweg SW, van Mechelen W, Lemmink KAPM, Pepping GJ, Diercks RL. No effect of a graded training program on the number of running-related injuries in novice runners: a randomized controlled trial. Am J Sports Med 2008;36(1):33-9 (N=532 novice runners; a 13 week graded programme "based on the 10% training rule" against an 8 week standard programme; injury rates of 20.8% against 20.3%, chi-square 0.016, df 1, P=.90; the abstract is what is cited) (DOI 10.1177/0363546507307505; PMID 17940147)
• Reid VL, Gleeson M, Williams N, Clancy RL. Clinical investigation of athletes with persistent fatigue and/or recurrent infections. Br J Sports Med 2004;38(1):42-5 (the original study behind the 68% cited by Kreher and Schwartz; 41 competitive athletes; the causes and their percentages; the concluding sentence of the abstract. The abstract is what is cited) (DOI 10.1136/bjsm.2002.002634; PMID 14751944; PMCID PMC1724742)
• Primary Healthcare Commission, Clinical Guideline for First-contact Physiotherapists on Assessment and Cross-disciplinary Management Approach for Common Musculoskeletal Problems in Primary Care Setting (the document's existence, publisher and publication date; the heading of table 3.1 and its three referral times "within same day", "within 1-2 days" and "within 2 weeks". This article states only that it exists and who it is for, and does not reproduce table 3.1): https://www.healthbureau.gov.hk/phcc/rfs/assets/pdf/home/discipline-based_guidelines/clinical_guideline_on_first_contact_assessment_and_cross-disciplinary_management_approach_for_common_msk_problems.pdf (self-dated First published Dec 2025; language: English, with the Chinese discipline-based guidelines page noting that the English version should be consulted; retrieved 3 August 2026)
• Leisure and Cultural Services Department, Fitness Rooms — Recognised Relevant Qualifications (the list of recognised courses for registering as a user of a Leisure and Cultural Services Department fitness room; that page does not concern the regulation of private fitness trainers): https://www.lcsd.gov.hk/tc/fitness/list.html (page's own revision date 29 January 2026; retrieved 7 August 2026)

This article was written from the sources listed above; information date 7 August 2026. It is general information and does not constitute medical advice. Individual diagnosis, investigations, medication and training decisions are for a doctor.

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#Further reading

• This site: Longevity science 2026: Bryan Johnson's protocol and the everyday basics
• This site: Reading laboratory and imaging reports
• This site: Low back pain
• Centre for Health Protection, Department of Health — healthy eating and physical activity: chp.gov.hk
• American College of Sports Medicine — overtraining guidance: ACSM Overtraining
• This site: Preventing injury in the gym
• This site: Cognitive behavioural therapy for insomnia