Do cold-water plunges really speed post-workout muscle recovery?

Post-workout cold plunges may be having a moment, but a new study dunks on the practice. After a tough workout, muscle recovery was no better in women who immersed themselves in chilly water than in women who didn’t. No recovery benefits came from a hot soak, either. The decidedly tepid results appear May 7 in PLOS One.

Thirty women completed five sets of 20 drop-jumps — grueling exercises that require a drop from a thigh-high box followed immediately by a powerful jump on the ground. Afterward, the exercisers, whose average age was 23, followed one of three recovery protocols: a 10-minute dip in 10° Celsius water, a 10-minute dip in 40° C water or nothing. Two hours after the first soak, the participants did another one. One, two and three days after the experiment, researchers looked for signs of muscle recovery, including muscle strength, soreness and swelling. They also measured creatine kinase, a marker of muscle damage in the blood.

Muscle recovery looked similar in all three groups of exercisers. Compared with the control group, neither the cold- nor the hot-water immersion groups differed much in muscle strength, soreness or swelling.

The results are some of the only data on women’s muscle recoveries; most studies on cold-water immersion have focused on men. And though some of those studies turned up benefits of cold-water immersion for recovery, those results are “far from conclusive,” says Vanessa Wellauer, who studies exercise and rehabilitation sciences at the University of Applied Sciences and Arts of Southern Switzerland in Landquart.

While the study throws a bit of cold water on the dipping trend, the effects of immersion may be more complex than simple muscle measurements. For instance, psychological factors such as beliefs and expectations matter here. “The subjective benefits, like feeling refreshed or less tired, can positively influence recovery perception and motivation, which are important factors in practice and competition,” Wellauer says. These benefits may take some of the chill off these findings.