Are ice baths and cold showers a cure-all after exercise?
You've probably seen images of athletes immersing themselves in ice-cold water after training... Since it was popularized by Wim Hof, known as "Iceman," the practice has become widespread in the fitness world before spreading to other disciplines. It must be said that it is believed to have many benefits!
Stéphane Perrey, University of Montpellier and Marc Julia, University of Montpellier
Prophylactic health effects, stimulation of the central nervous system, improved muscle performance and recovery after exercise... This strategy of active recovery after physical activity, a fundamental part of any serious training program, has become one of the most popular approaches over the last ten years.
Although many athletes, both professional and amateur, use it, they are not necessarily well informed about the real benefits of this practice and its effectiveness. If you grimace at the idea of plunging into a simple swimming pool, you may have more questions... Are ice baths, cold showers, and cryotherapy chambers at -80°C (in specialized facilities), if you are highly motivated, really beneficial? Or is it just a fad? Who can benefit from it?
To answer these questions, it is best to start by looking at how cold affects our bodies...
A myriad of physiological responses
The most important physiological adaptation to extreme cold is undoubtedly the narrowing of blood vessels, or "vasoconstriction, " which is probably intended to reduce body heat loss. Ice baths thus cause a rapid increase in blood pressure in the short term, which in turn leads to an increase in heart rate and respiration.
Because blood vessels constrict, blood flow to submerged areas slows down considerably in terms of volume. This can be beneficial in combating excessive microbleeding and microinflammation caused by certain physical activities involving repeated impact. If exposure to cold is prolonged, the tips of our nerve endings, just beneath our skin, can reduce sensation to the point of numbness.
There is also evidence that cold water swimming can modulate the production of pro-inflammatory cytokines, small cellular proteins that activate the body's inflammatory response—which can have an analgesic (pain-reducing) effect.
But be careful: an ice bath should not be taken for long periods of time, due to the real riskof hypothermia, which can have serious consequences.
What are the potential benefits?
Given these physiological changes, why do athletes choose this method after exercise? The most common reason is their belief that it will "cure" sore muscles.
What is established is that ice baths reduce blood flow to submerged areas, which reduces edema (swelling), aided by the hydrostatic pressure effect. And, as mentioned above, cold has an analgesic effect, which is useful in the case of traumatic injuries—hence the use of ice packs for local injuries or to relieve post-operative pain. But beware, cold does not heal: the pain will return when the temperature starts to rise again. Its use is therefore only temporary and symptomatic.
What about muscle pain after strenuous exercise? What about soreness? It has been suggested that, due to vasoconstriction of the blood vessels, muscle damage may have a weaker inflammatory response, resulting in less muscle pain.
Over the past 10 years, various studies have shown that immersion in cold water can improve, to a certain extent, the treatment of delayed muscle soreness (24-48 hours). A study of elite rugby players, conducted over three weeks of competition, concluded that there was a reduction in muscle fatigue and a slight decrease in soreness. Separate research has also suggested a modest positive effect on muscle pain perceived by MMA athletes. However, there was no improvement in performance.
However, there is also data suggesting that cooling is not necessarily beneficial for post-exercise recovery—the perceived benefits may be due to a placebo effect (when we are convinced that it works). Cryotherapy (3-4 minutes at -85°C), cold water immersion (10 minutes at 10°C), and a placebo group were compared after weight training. The differences were insignificant, and some biological and performance markers even favored the placebo...
A meta-analysis also reported that the proposed beneficial effects of cold water immersion (10°C and 13 minutes on average) appeared to be based more on subjective markers (perception of pain and perceived exertion) than objective markers (blood markers).
To summarize, cold water immersion, mainly due to its ability to lower tissue temperature and blood flow, can reduce muscle pain and edema, but its effects on muscle recovery and performance are highly debated. The beneficial effects on post-exercise recovery appear to be context-specific, and several factors such as body composition, gender, type of physical activity performed, and training status must be taken into account.
[More than 85,000 readers trust The Conversation's newsletters to help them better understand the world's major issues. Subscribe today]
Friend or foe for muscles?
Recent data has shown that cooling down after exercise can be detrimental when the goal is to build muscle mass (hypertrophy).
A study indicates that acute exposure to cold reduces skeletal muscle protein anabolism (enabling muscle growth) while increasing catabolism (leading to breakdown). This has no effect on muscle strength.
Another study examined the effects of active recovery and ice baths on adaptations to weight training. After 12 weeks, ice baths reduced muscle growth... and strength gains! The acute (negative) effects of cold water immersion thus appear in the longer term, possibly as a result of a decrease in circulating testosterone.
If gaining muscle mass and strength is a goal (as part of a training plan, away from competitions), then immersion in cold water should be avoided as a recovery strategy after exercise.
So... Taking ice baths?
Potentially costly and time-consuming, ice baths (10-15°C for 11-15 minutes) are therefore not a panacea...They can help reduce delayed muscle soreness, but so can active recovery, such as walking—which is cheaper and much easier to do!
While in the short term, there may be a faster recovery of strength capacity, reduced inflammation, and less muscle soreness, over a longer period of time, immersion in cold water has no effect, positive or negative, on physiological adaptations.
Above all, cold water is not suitable for people who follow a weight training program—bodybuilders or weightlifters who want to develop muscle mass and strength... But at the same time, they may find it beneficial to enjoy the benefits of an ice bath after a very intense workout or competition.
The use of the bath will therefore depend on your sporting activities and your goals!
If you don't need to build a lot of muscle, you can use it. This may apply to many athletes as well as combat sports. And even if strength and muscle mass are important, weigh the pros and cons... For example, in a competition over two consecutive days, with sessions several times a day, the benefits of faster recovery will outweigh any reduction in muscle growth.
And you don't need to take an ice bath after a low-intensity workout: your muscles won't have accumulated enough damage to justify its use.
Above all, if you suffer from high blood pressure or cardiovascular disease, an ice bath may prove to be too much of a shock for you and your heart! Medical advice is necessary. So be careful... As always, the important thing is to know your body, the goals you are aiming for, and the effect of the techniques you are using.
Stéphane Perrey, University Professor of Exercise Physiology/Integrative Neuroscience, Director of the Research Digital Health in Motion Research Unit, University of Montpellier and Marc Julia, Sports Physician, Associate Researcher in Sports Science, University of Montpellier
This article is republished from The Conversation under a Creative Commons license. Readthe original article.