Cold-water baths – often called ice baths even though the water isn’t always that cold – are a popular post-workout ritual for many athletes.
The idea is that by reducing pain and inflammation they shorten recovery time, allowing you to do more workouts per week, month or year than would otherwise be possible.
Since workouts make you strong, the reasoning goes, finding a way to squeeze in a few more should cause you to get even stronger, more quickly.
But not so fast: it may be better to let nature take its own sweet time. However much better ice baths may make you feel, they appear to impede muscle building rather than facilitate it, scientists say.
In a study published in The Journal of Physiology, researchers from The Netherlands examined the effect of cold-water treatment on the rate of muscle protein synthesis in college-aged men undergoing a two-week weightlifting program.
After each workout, the participants immersed one leg in cold water (eight degrees Celsius) for 20 minutes, but not the other.
After the first session, says study author Cas Fuchs from Maastricht University, the volunteers were given a protein/carbohydrate recovery drink containing amino acids labelled with a non-radioactive form of carbon that could be used as a tracer for how well their muscles absorbed amino acids.
When the volunteers’ leg muscles were then biopsied, Fuchs says, the researchers found fewer of the labelled amino acids in their cold-water-bath legs than in their unchilled ones.
That’s significant because amino acids are the building blocks of proteins, necessary for muscle strengthening and repair.
“We wanted to see if the process is affected by cold-water immersion,” Fuchs says. “We [found] that the cooled leg was less capable of muscle-protein synthesis.”
Similarly, they found that at the end of two weeks of training, the cold-water-immersed legs had built less new protein overall than the non-immersed legs.
This doesn’t mean ice baths aren’t good for injuries such as sprained ankles, where reducing swelling is often a primary goal. “Injuries and exercise recovery are very different things,” Fuchs says.
But it does mean that athletes and coaches might want to reconsider their reliance on ice baths as a recovery aid.
“Everyone wants to get the most out of their workouts,” Fuchs says, “[but] our research suggests that if the primary aim is to repair and/or build muscle, athletes should not use ice baths.”
Other scientists agree. “This new research is important,” says Jonathan Peake, a sports scientist at Australia’s Queensland University of Technology, who was not part of the study team.
Previous studies, including ones from his group, had showed that ice baths may have deleterious effects on overall strength gain.
But the new study, he says, adds to the case by demonstrating “quite emphatically” that one of the ways this may happen is by suppressing the rate of muscle protein synthesis.
Richard has more than just a scientific interest in this story. As well as a regular contributor to Cosmos, he coaches the 240-member Team Red Lizard running club in Portland, Oregon, and has coached several competitors in the US Olympic Team marathon trials through the last three Olympiads. He also has written dozens of training-related articles for running magazines and co-authored two training books.
Richard A Lovett
Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.
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