Ice baths ease soreness, and 5 °C is no better than 15 °C

Cold-water immersion is one of the most popular recovery rituals in sport, yet the practical details have never been settled. Athletes and gym-goers plunge into everything from near-freezing tubs to merely chilly pools, often on the assumption that colder means better. The research to date has produced inconsistent conclusions about whether water temperature actually changes the outcome. This analysis set out to answer two questions at once: does a single post-exercise cold plunge genuinely reduce soreness and muscle damage, and does the temperature of the water matter?

The authors ran a systematic review and meta-analysis following PRISMA guidelines, searching PubMed, Web of Science, SPORTDiscus and SCOPUS. They included only studies using a single session of cold-water immersion, which left 52 studies in the analysis. Outcomes were delayed onset muscle soreness plus two blood markers of muscle damage, creatine kinase and myoglobin. Effects were expressed as standardised mean differences, and subgroup analyses compared water at approximately 5 °C, 10 °C and 15 °C. The protocol was not prospectively registered, and the authors flag the temperature comparisons as exploratory.

Overall, cold-water immersion produced statistically significant moderate-to-large benefits: soreness fell with an effect of 0.81, creatine kinase by 0.64 and myoglobin by 0.93. The temperature story ran against intuition: soreness relief was numerically smaller at around 5 °C, an effect of 0.2, than at around 10 °C or 15 °C, where effects were 0.8 and 0.9. That difference between temperature groups was not statistically significant. The blood markers fell across all temperature ranges, again with no significant differences between them, and wide prediction intervals mean the benefits may not reproduce everywhere.

This pooling strengthens the case that a post-exercise cold plunge reduces perceived soreness and markers of muscle damage, which has been the dominant but contested view. Where it genuinely adds something is on temperature: it finds no evidence that colder water works better, and if anything the numbers lean the other way. Because the subgroup analyses were exploratory and the included studies varied substantially, the authors conclude that no water-temperature range can currently be considered superior. Whether ice baths affect longer-term adaptation to training is a separate question this analysis did not address.

For anyone who already uses cold plunges after hard sessions, this is reasonable support that they do take the edge off soreness. It is also a reason to be sceptical of the macho logic that the water must be barely above freezing: the coldest tubs showed no advantage here, and numerically the mildest relief. The honest reading is that the general effect looks real on average but inconsistent across settings, and the ideal temperature, if one exists, has not been identified.