A dip in cold water may reduce “bad” body fat in men and reduce the risk of diseases like diabetes, suggests a large scientific study published in the peer-reviewed journal International Journal of Circumpolar Health.
The authors say many of the 104 studies they analyzed showed significant effects of cold-water swimming, including on “good” fat that helps burn calories. This may protect against obesity and cardiovascular disease, they add.
However, the review was overall inconclusive on the health benefits of cold-water bathing, an increasingly popular hobby.
Much of the available research involved small numbers of participants, often of one sex, and with different water temperatures and salinity compositions. Additionally, it’s unclear whether or not winter swimmers are inherently healthier, says the scientific expert team of review authors from UiT The Arctic University of Norway and the University Hospital of North Norway.
“It is clear from this review that there is increasing scientific support that voluntary exposure to cold water can have some beneficial health effects,” explains lead author James Mercer of UiT.
“Many of the studies showed significant effects of cold water immersion on various physiological and biochemical parameters. But whether these are beneficial to health or not is difficult to assess.
“Based on the findings of this review, many of the health benefits claimed from regular colds may not be causal. Instead, they can be explained by other factors, including an active lifestyle, stress management skills, social interactions, and a positive mindset.
“Without further meaningful studies, the topic will continue to be discussed.”
Weight loss, better mental health, and increased libido are among the numerous health and well-being claims made by devotees of regular cold water immersion or arising from anecdotal accounts.
This activity takes many forms such as: B. swimming in cold water in winter, and is experiencing growing interest worldwide.
The primary objective of the review was to determine whether voluntary exposure to cold water has any health effects on humans. The methodology involved a detailed search of the scientific literature.
Excluded from the review were studies in which participants wore wetsuits, accidentally immersed themselves in cold water, and had water temperatures greater than 20 degrees Celsius.
Topics covered by the studies eligible for review included inflammation, adipose tissue, blood circulation, the immune system, and oxidative stress.
Being immersed in cold water has a major impact on the body, triggering a shock reaction such as an increased heart rate.
Some studies have provided evidence that cardiovascular risk factors are actually improved in swimmers who have adapted to the cold. However, other studies suggest that the heart’s workload is still elevated.
The review provided insight into positive associations between cold-water swimming and brown adipose tissue (BAT), a type of “good” body fat that’s activated by cold. BAT burns calories to maintain body temperature, unlike “bad” white fat, which stores energy.
Exposure to cold water—or air—also appears to increase the production of adiponectin by adipose tissue. This protein plays a key role in protecting against insulin resistance, diabetes, and other diseases.
Repeated cold water immersion during the winter months significantly increased insulin sensitivity and decreased insulin concentrations, the review found. This was for both novice and experienced swimmers.
However, the authors point out that the profile of the swimmers participating in the studies was very different. They ranged from elite swimmers or established winter swimmers to those with no prior winter swimming experience.
Others were not pure ice bathers but used cold water immersion as a post-treatment exercise.
Education about the health risks associated with bathing in icy water is also needed, say the authors. These include the effects of hypothermia, as well as heart and lung problems that are often associated with cold shock.