Cold-water immersion lacks superiority for recovering muscle strength

Cold-water immersion is a popular post-workout recovery strategy, but new research suggests it may offer no greater benefit to muscle strength recovery than heat-based methods. 

The study, published in the Journal of Thermal Biology, investigated how different thermal recovery strategies affect muscle recovery following exercise-induced muscle damage. 

Researchers led by the University of East London found that while heat-based interventions altered several physiological markers associated with cellular stress and muscle repair, neither heat nor cold resulted in superior recovery of muscle strength over a 72-hour period. 

The research involved 40 healthy, physically active adults who completed an intensive exercise protocol designed to induce temporary muscle damage and delayed onset muscle soreness. 

 Participants were randomly assigned to one of four recovery strategies: 

• 30 minutes of hot-water immersion at 42°C 
• 15 minutes of cold-water immersion at 9°C 
• 30 minutes of hot-air exposure at 30°C 
• Passive recovery at room temperature 

Researchers then monitored changes in muscle strength, muscle soreness and a range of molecular markers associated with muscle damage and inflammation over the following 72 hours. 

Immediately following exercise, muscle strength decreased by approximately 36% across all groups. Although strength gradually recovered over the monitoring period, no statistically significant differences were observed between the four recovery strategies. 

However, the different recovery approaches produced distinct physiological responses. Participants receiving heat-based treatments showed increased expression of heat shock protein 72 (HSP72), a cellular stress protein associated with protective and repair-related processes within muscle. In addition, concentrations of creatine kinase-MM (CK-MM), a marker commonly associated with muscle damage, returned towards baseline more rapidly in the heat-based recovery groups than in the cold-water immersion group. 

These findings suggest that heat-based recovery strategies may influence some of the biological processes involved in recovery following muscle-damaging exercise. However, these physiological changes did not translate into significantly greater improvements in muscle strength or reductions in soreness during the 72-hour recovery period. 

Cold-water immersion remains one of the most popular recovery strategies used by athletes and recreational exercisers alike. Our findings suggest that heat-based recovery methods produce different physiological responses following strenuous exercise, particularly in relation to markers associated with cellular protection and muscle repair. 

We observed increases in heat shock protein expression and a faster return towards baseline for some markers associated with muscle damage in the heat conditions. However, it is important to recognize that these responses did not result in significantly greater recovery of muscle strength or lower levels of soreness over the following 72 hours. 

The findings highlight the complexity of recovery and suggest that changes at a physiological level do not necessarily translate into immediate improvements in functional recovery. Further research is needed to understand whether repeated exposure to heat-based recovery strategies might produce longer-term benefits." 

Dr. Freya Bayne, Lecturer in Sport and Exercise Science, University of East London and lead author of the study

The study was carried out in collaboration with researchers at London South Bank University (LSBU), Maastricht University, Univ Montpellier, CREPS Montpellier Font-Romeu and De Montfort University Dubai.