Post-workout ice baths and increased dietary protein intake have long been used by athletes as strategies to build muscle. Findings from a new study suggest that ice baths may hinder muscle protein synthesis by interfering with dietary protein uptake into muscles.

The study participants included 12 healthy young men who engaged in a single resistance‐type exercise session and then immersed both their legs in water for 20 minutes. One leg was immersed in cold water (8°C, 46°F) while the other leg was immersed in water that was slightly warmer than room temperature (30°C, 86°F). Afterward, the participants consumed an amino acid-rich beverage.

The authors of the study monitored the uptake of the amino acids and subsequent muscle protein synthesis for two weeks. Analyses of blood, saliva, and muscle tissue revealed that cold water immersion after resistance‐type exercise reduces muscle protein synthesis, which could impair muscle conditioning.

Interestingly, an older study found that cold water immersion reduced the risk of cancer and enhanced longevity in mice. The contradictory findings of these two studies suggest that cold exposure may be harmful in certain contexts, but beneficial in others, and that timing of the exposure is critical.

• Link to study abstract.