Post-exercise rehydration: a randomized cross-over trial comparing a 100% fruit juice, a glucose-based sports drink, and water
Study Details
This new study compared 100% fruit juice, a glucose-based sports drink and water for post-exercise rehydration in 17 adults after ~2% body mass loss 🔍
Participants cycled in ~35°C heat until they lost ~1.9% body mass 🌡️
They then consumed fluid providing water equal to 150% of body mass lost over 1 hour💧
🍉 The fruit juice contained ~5.9% carbohydrate, relatively little sodium and ~35 mmol/L potassium
🥤 The sports drink contained ~6.3% carbohydrate and ~20 mmol/L sodium
Importantly, drinks were matched for actual water content, rather than total beverage volume ⚖️
Key Findings
🚽 Total urine production over 5 hours did not significantly differ between fruit juice, sports drink and water
💧 Water retention was also similar: ~42% with fruit juice, 37% with sports drink and 35% with water
📊 Net water balance did not differ significantly between beverages
This suggests that, when actual water intake is matched, the sports drink did not provide a clear rehydration advantage over plain water 🧐
🧃 Fruit juice therefore performed similarly to both sports drink and water for restoring hydration
Blood glucose responses differed substantially between drinks:
📈 The sports drink produced the highest 2-hour glucose response, fruit juice was intermediate and water was lowest
⚠️ Hyperglycaemia occurred in 44% of participants after the sports drink, but in none after fruit juice or water
📉 Hypoglycaemia occurred in 75% after water, 19% after fruit juice and none after the sports drink
🧃 Fruit juice therefore produced a more moderate blood glucose response despite a carbohydrate concentration similar to the sports drink
🚨 Three additional participants withdrew because of diarrhoea after consuming the fruit juice
🥤 This likely reflected the unusually large ~2.3 L juice intake within 1 hour, providing ~136 g carbohydrate and an estimated ~68 g fructose
Conclusion
100% fruit juice may be a viable “food-first” rehydration option, but large volumes consumed rapidly may increase GI risk ✅
Reference
https://pubmed.ncbi.nlm.nih.gov/42672944/
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