(Montreal) Although ice baths are better known to the general public, it is in fact hot baths that allow the muscle fibers of high-level athletes to recover better, a team from Laval University has found.
The researchers found that heat accelerates blood circulation, promotes vasodilation of the vessels and helps relax muscles and tendons, which speeds up the recovery process.
Ice baths, on the other hand, are useful for central nervous system recovery.
“It’s relatively new for hot baths, for muscles,” explained one of the study’s authors, doctoral student Abdellah Hassar from the Quebec institution’s faculty of medicine.
“We did some very thorough tests at the muscular and intracellular level to see a little bit what happens in terms of acceleration of recovery. And we noticed that there is indeed a much faster recovery at the muscular level when you take a hot bath.”
Working with Professor François Billaut, an expert in performance physiology, Hassar and his colleagues demonstrated that just one small degree could make all the difference: the thermal shock produced by water heated to 40°C, compared to 41°C, was therefore not sufficient to induce muscle recovery.
Other studies have shown that cold or ice baths promote recovery of the central nervous system, which is especially used during explosive sports such as running, sprinting, throwing or weightlifting.
By promoting the dilation of blood vessels, the researcher said, hot baths allow the blood to bring more “food” to the muscle, which will allow it to recover more quickly. The heat will also have the effect of relaxing and loosening the muscle, which will promote better sleep.
The body, Mr. Hassar said, “tends to do the opposite of what you do to it.”
“After an ice bath, you feel a sensation of warmth in your skin because your body is protecting itself,” he explained. “With a hot bath, it does the opposite, it cools down, and we need to cool our bodies down well to recover and sleep well.”
Thirty young athletic men were recruited for this study. The researchers targeted only one muscle group to save time.
After the training, some participants were immersed in warm water from the waist down until their body temperature reached between 38.5 and 39 °C for about 25 minutes. Others took a cold bath for eleven minutes, in water kept at a temperature of 11 °C. A third group took a lukewarm bath for 25 minutes at 36 °C.
Hassar and his colleagues therefore conclude that optimal performance requires both hot and cold baths. A hot bath would be appropriate after a high-intensity session. A cold bath, which promotes central nervous system recovery, would be appropriate between training blocks, while the athlete has a day or two of rest.
Hot baths could also be beneficial between events. At the Olympics, Hassard said, athletes could do a soak between prequalification, qualification and the final to speed recovery from muscle damage.
“The combination of the two would be perfect for optimal recovery,” concluded Hassar, who is himself a world-class hammer thrower.
The findings of the study were published in the journal Medicine & Science in Sports & Exercise.