The ice bath you step into right after lifting quietly works against the reason you lifted. A 2024 meta-analysis, honestly titled "Throwing cold water on muscle growth," pooled eight trials and found that cold immersion within fifteen minutes of the last rep blunts the growth signal a hard set switches on, with about a 96 percent probability it points the wrong way for building size.
The effect is modest (a standardized mean difference of about minus 0.22) and it lands harder on size than on strength. So keep the split simple:
- After a session for growth, let the cold wait
- On rest days and in-season, plunge and enjoy it
- Endurance work seems largely untouched
The cold does honest work. It just does not do this one.
