Research
Energy balance
Maintaining euhydration and minimizing dehydration (body mass loss <2%) during exercise in the heat is critical to prevent impaired aerobic performance and exacerbated cardiovascular strain.
Start your event well-hydrated by drinking 6 mL of water per kg of body weight every 2-3 hours before you start. During the event, drink fluids containing 0.5-0.7 g/L of sodium. Do not rely solely on thirst, as you will likely be dehydrated by the time you feel it, which hurts performance.
GoodSupportsHIGH confidence
In addition, athletes should initiate competition and training in a euhydrated state and minimize dehydration during exercise.
Why this rating
Consensus statement acknowledging debate but leaning towards impairment.
Source
Consensus recommendations on training and competing in the heat
Sébastien Racinais et al. · Scandinavian Journal of Medicine and Science in Sports · 2015
DOI 10.1111/sms.12467
clinical_guidelineCited 245×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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