Dehydration may blunt the amino acid response to post-exercise protein 💧

One more reason to nail hydration during exercise.

Exercise-Induced Dehydration Limits the Effectiveness of Post-Exercise Whey Protein Supplementation in Healthy Young Men

Study Details

This new study examined whether exercise-induced dehydration alters the circulating amino acid response to 45 g whey protein in 13 healthy young men 🔍

Participants completed the same intermittent running protocol under three hydration conditions, producing body-mass losses of 2.20%, 1.18% and 0.27% 🏃

Within 5 min of exercise, all participants consumed 45 g whey protein in 450 mL water 🥤

Key Findings

📈 Whey increased circulating amino acids in all conditions, but the response was reduced when participants finished exercise ~2.2% dehydrated

🩸 At 60 min, total amino acids, BCAAs, leucine, isoleucine and glutamine were all significantly lower after 2.2% dehydration than after either partial or full fluid replacement

📊 The 0–120 min amino acid response was also lower for total amino acids, BCAAs, isoleucine and glutamine with 2.2% dehydration

↔️ Importantly, there were no meaningful differences between ~1.2% and ~0.3% body-mass loss

💡 This suggests that replacing around 50% of exercise fluid losses may have been sufficient to preserve the early amino acid response, with no additional benefit from replacing 100%

🤢 GI symptoms remained very low and did not differ between conditions, meaning impaired amino acid appearance occurred without obvious gastrointestinal discomfort

🧬 Potential mechanisms include reduced splanchnic blood flow, slower gastric emptying and impaired intestinal absorption, although these were not directly measured

⚠️ Muscle protein synthesis was not measured, so lower circulating amino acids cannot automatically be interpreted as reduced muscle protein synthesis or recovery

Conclusion

Finishing exercise substantially dehydrated may reduce the early availability of amino acids from post-exercise whey, so maintaining at least partial fluid replacement during exercise could help preserve the intended recovery benefit of protein intake ✅

Reference

https://www.mdpi.com/2072-6643/18/19/3267

---

Performance Nutrition Digest is powered by Healthspan Elite ⚡️

Healthspan Elite is a science-led sports nutrition range developed in collaboration with leading experts to support athletic performance, recovery, and health.

Use code: TCDIGEST25 for 25% off at https://www.healthspanelite.co.uk/ 💪

---