Heat and dehydration were linked to greater carbohydrate use during endurance exercise
This abstract-based summary examines exercise fuel use across temperature and hydration conditions. The results do not establish performance benefits.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Carbohydrate oxidation and glycogen use were higher in hot conditions than in temperate conditions. Both measures were also higher overall during dehydration. These findings describe exercise metabolism, but do not establish how much carbohydrate an individual needs, whether performance changes, or which fueling approach would work best for them.
Few participants were female. The abstract provides no confidence intervals or detailed exercise protocols, limiting assessment of precision and applicability across endurance activities.
What researchers found
Carbohydrate oxidation
During exercise lasting at least 15 minutes, oxidation was higher in hot versus temperate conditions by 0.29 standard deviations—a standardized difference, not a percentage or carbohydrate amount. The P value measures evidence against no difference, not the difference’s size.
What the measurements capture
The review measured respiratory exchange ratio, carbohydrate oxidation and glycogen use during exercise. These outcomes describe metabolism; the abstract does not quantify whether the observed differences changed endurance performance.
Interpreting the hydration results
Dehydration-related carbohydrate oxidation was statistically higher in hot conditions, but the temperate-condition result was not significant. This alone does not establish different effects across temperatures or rule out an effect in temperate conditions.
The original publication
The Effect of Heat Stress and Dehydration on Carbohydrate Use During Endurance Exercise: A Systematic Review and Meta-Analysis.
Mougin L, Macrae HZ, Taylor L et al.
Sports Med · 2025
- PubMed ID
- 40835807
- Record checked
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