Electrolytes and sodium in racing: what ACSM and the hyponatremia consensus say
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What they are
The AIS describes electrolyte supplements as powders, tablets or ready-to-drink products designed to replace fluid and electrolytes, mainly sodium and potassium, lost in sweat or other body fluids.3 They differ from gels and carbohydrate drinks, which supply energy: for those use Fuel and the marathon carbohydrates article.
What the ACSM says
The 2007 ACSM position stand sets the goal during exercise as preventing excessive dehydration and excessive changes in electrolyte balance that compromise performance. Because sweating and sweat salts vary a lot between people, it recommends tailored plans. During exercise, drinks with electrolytes and carbohydrate can give benefits over water alone in certain circumstances.1
The risk of excess
- Exercise-associated hyponatremia: the 2015 consensus names sustained excessive fluid intake (water, sports drinks) beyond losses as the single most important risk factor. Symptomatic cases almost all occurred in people who kept or gained weight during the activity.2
- Sodium in the drink: sports drinks are hypotonic to plasma (about 10-38 mmol/L sodium in those considered), so an excessive volume overwhelms the protective effect of their sodium.2
- Other factors: duration over 4 hours, little experience or training, slow pace, high or low body mass index, fluids always available.2
- Thirst: per the consensus, thirst is an adequate stimulus to prevent excessive dehydration and markedly lowers the risk of hyponatremia in all sports. Evidence for sodium loss as the main cause of symptomatic cases is scarce, even in long hot races.2 This does not erase cases of sodium loss in extreme events: the consensus considers them less frequent.
- Cramps: experimental and observational studies suggest exercise cramps may reflect neurological changes from fatigue rather than uncompensated water and sodium losses, at least in some cases.2
Limits and safety
- After a long race, if neurological symptoms appear (for example confusion), even within the following 24 hours, urgent medical help is needed: the consensus says so for people with hyponatremia even without initial symptoms.2
- With heart or kidney disease, with medicines or on a controlled-salt diet a doctor decides: the sources read concern healthy athletes.
- The sources date from 2007 and 2015: newer studies not read. No product assessed, no brands, no sodium amount given.
How we reviewed it
Document review: 2007 ACSM position stand (abstract), 2015 international hyponatremia consensus (text), AIS page. Not every full text. No WOLF LAB tests.
Limits. Sources from 2007 and 2015, nothing more recent read. Healthy athletes. No product, brand or sodium amount assessed. Not medical advice.
Sources
- Sawka MN et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 2007. PubMed.
- Hew-Butler T et al. Statement of the 3rd International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. British Journal of Sports Medicine, 2015. BJSM.
- AIS (Australian Sports Commission). Sports supplements, Group A. AIS.
Sources read on 31 October 2026: abstract (ACSM) and the text of the 2015 consensus for the sections on risk, thirst and cramps; not every full text. General information, not medical advice. No WOLF LAB tests.