Sports drinks buy a small endurance edge in warm conditions, nothing for strength

Carbohydrate-electrolyte drinks are among the most heavily used sports products, and exercising in warm or hot weather is exactly when athletes reach for them. Whether they genuinely improve performance across moderate to hot temperatures, and across different kinds of effort, is less settled than the marketing suggests. This review took a deliberately wide temperature criterion, treating 22 °C as an operational lower boundary spanning mildly warm to hot conditions rather than a physiological threshold for heat stress. It then asked what the randomised evidence actually shows for these drinks against water or a non-caloric placebo.

The review was registered on PROSPERO before work began, and five databases were searched up to May 2026 for randomised controlled trials comparing acute carbohydrate-electrolyte supplementation with water or a non-caloric placebo during exercise at these temperatures. Twenty-one studies covering 316 participants contributed 32 separate effect estimates, which were combined using a three-level model built to handle multiple results from the same study. The certainty of the evidence was graded, risk of bias was assessed, and sensitivity analyses re-ran the numbers after excluding trials conducted at the cooler end of the range.

Overall, the drinks were associated with a small average performance advantage, a standardised effect of 0.37, but the range of plausible effects in future settings crossed zero, running from -0.21 to 0.96. Split by performance type, the benefit concentrated in aerobic endurance, at 0.45, while evidence for anaerobic endurance, explosive power and strength remained inconclusive. Excluding trials at 22 to 25 °C left the estimate positive, at 0.41 above 25 °C and 0.36 at 28 °C or hotter, but those prediction intervals still crossed zero. Neither ambient temperature nor exposure duration significantly moderated the effect.

A small endurance benefit from carbohydrate during prolonged work fits the broader sports-nutrition picture, and this analysis extends it specifically to warm and hot settings. Its more interesting contribution is the boundary it draws: the trials compared drinks within the same environmental condition, never hot exercise against temperate exercise, so the results cannot show that these drinks offset the performance loss heat itself causes. The wide spread of effects also means some events and individuals may see no benefit at all, and the strength and power domains remain genuinely open questions.

If you drink a carbohydrate-electrolyte product during long warm-weather endurance sessions, this is a reason to think it offers a small average edge over water. It is equally a reason to keep expectations modest: the effect is small, inconsistent across studies, and does not extend to strength, power or short anaerobic efforts on this evidence. And nothing here shows the drinks counteract heat as such, since no trial compared hot conditions against cooler ones; what they fuel is the endurance work itself.