By Linda Carroll

(Reuters Health) – New research throws cold water on a popular exercise recovery regimen, finding that ice baths after a workout may actually impede muscle building.

Researchers found that cold or ice baths can impede the generation of new protein in the muscles, according to the report published in the Journal of Physiology.

“The take-home message from our study is that athletes aiming to grow and/or repair their muscles should avoid cold water immersion after exercise,” said study leader Cas Fuchs, a researcher at Maastricht University in the Netherlands.

Athletes often assume that cooling is good for recovery after a workout because they say “they ‘feel’ better after post-exercise cooling,” Fuchs told Reuters Health by email. “They feel less muscle soreness and believe that they are able to recover faster, and thereby being able to exercise faster again.”

But feelings can be deceptive, Fuchs said. While cooling can knock-back muscle swelling and soreness, “in our study we found that post-exercise cooling lowers the ability of our muscles to make new proteins that are essential to repair and build our muscles,” he explained. “Therefore, if you want to repair and grow your muscles after a workout, it is smart to avoid cooling.”

To take a closer look at the impact of a cold or iced bath after workouts, Fuchs and his colleagues recruited 12 healthy young men, with an average age of 21, for a series of experiments. After the men did some lower-body weight lifting – leg presses and extensions – they were asked to place one leg in icy water and the other in room temperature water. Afterward, the men consumed a protein drink.

When the researchers examined muscle biopsies from the men’s legs, they found less protein synthesis in the cooled leg than in the one that had been in room-temperature water. “Less muscle protein synthesis very likely translates into less muscle building in the long-term,” Fuchs said.

While the new study is interesting, “I can’t imagine anyone’s practice changing because of one small study,” said Dr. Melissa Leber, an associate professor of orthopedics and director of emergency department sports medicine at the Icahn School of Medicine at Mount Sinai Hospital in New York City.

“Elite athletes all the way from high school to college to pros use ice baths to help with recovery,” Leber said. “They all have ice baths in their training rooms to help legs recover so they can train the next day.”

This article suggests “that unless there is an injury, like a muscle pull or tendonitis, this is not the best way to recover and it potentially hinders muscle building,” Leber said. “They feel that it’s possible that cold water baths are not doing what we intend them to do.”

But, said Leber, “the study has a huge limitation: there are just 12 athletes. Plus, they are only testing resistance training not aerobic exercise.”

And while it might be argued that the findings would be pertinent for weight lifters, “they are not typically the ones who are going to use ice water baths,” Leber said, adding that ice water baths are more typically used by people doing sports such as soccer and football.

Leber would like to see more studies on the topic. “It’s an interesting possibility for future research, she said. “Maybe we will need to find a way for better recovery than just ice water baths after exercise.”

SOURCE: Journal of Physiology, online December 1, 2019.