Protein ingestion before sleep improves postexercise overnight recovery.
Level 2 - randomized trial
Controlled human physiological trial with stable isotope tracers
PubMed 22330017 · doi:10.1249/MSS.0b013e31824cc363
What was done
Sixteen healthy young men completed a single bout of evening resistance exercise (2000 h) following a day of standardized diet. All participants consumed a post-exercise recovery drink (20 g protein, 60 g carbohydrate) at 2100 h. At 2330 h (30 minutes before sleep), subjects ingested a drink with (PRO) or without (PLA) 40 g of intrinsically labeled casein protein. Using continuous intravenous isotope infusions with blood and muscle sampling over 7.5 hours, researchers measured digestion and absorption kinetics, whole-body protein balance, and mixed muscle protein synthesis rates overnight.
What was found
Casein was digested and absorbed during sleep, sustaining elevated circulating amino acids overnight. Pre-sleep protein ingestion increased whole-body protein synthesis rates (311 ± 8 vs 246 ± 9 μmol·kg per 7.5 h, P < 0.01) and improved net protein balance (61 ± 5 vs -11 ± 6 μmol·kg per 7.5 h, P < 0.01) compared with placebo. Mixed muscle protein synthesis rates were ~22% higher with protein ingestion, reaching borderline statistical significance (0.059 ± 0.005 %·h vs 0.048 ± 0.004 %·h, P = 0.05).
Why it matters
This study shows that protein ingested immediately before sleep is effectively digested and absorbed, stimulating muscle protein synthesis and shifting overnight whole-body net balance from negative to positive after evening resistance training.
Limits
The study had a small sample size (n = 16) and included only healthy young males. It measured acute, single-night physiological kinetics rather than chronic adaptations in muscle mass or strength. Mixed muscle protein synthesis rates achieved only borderline statistical significance (P = 0.05).
Cited by
- supports Studies by Luc van Loon show that ingesting a bolus of protein directly before sleep increases overnight muscle protein synthesis.