Soaking in cold water can reduce ‘bad’ body fat in men and reduce the risk of conditions such as diabetes, suggests an important scientific review published in a peer-reviewed journal. International Journal of Environmental Health.
The authors say that many of the 104 studies they analyzed showed significant effects of swimming in cold water, including ‘good’ fats that help burn calories. They add that this may protect against obesity, cardiovascular disease.
However, the review was generally inconclusive on the health benefits of cold water bathing, an increasingly popular hobby.
Most of the available studies involved a small number of participants, usually of one gender and with different water temperature and salt composition. It’s also unclear whether winter swimmers are naturally healthier, say the team of scientific experts from UiT Norwegian Arctic University and Northern Norway University Hospital.
“It is clear from this review that there is growing scientific support that voluntary exposure to cold water may have some beneficial health effects,” says lead author James Mercer of UiT.
“Most studies have shown significant effects of cold water immersion on various physiological and biochemical parameters. However, the question of whether these are beneficial to health is difficult to assess.
“Based on the results of this review, many of the health benefits of regular cold exposure may not be causal. Instead, they may be explained by other factors such as an active lifestyle, educated stress management, social interactions, and a positive lifestyle mindset.
“Without further conclusive studies, the issue will remain a topic of discussion.”
Weight loss, better mental health, and increased libido are among the numerous health and well-being claims made by or anecdotal cases by followers of regular cold water dips.
This activity takes many forms, such as swimming in cold water in winter, and is of increasing interest worldwide.
The main objective of the review was to determine whether voluntary exposure to cold water had health effects in humans. The methodology included a detailed search of the scientific literature.
Studies in which participants wore wet clothing, were accidentally immersed in cold water, and had water temperatures above 20 degrees Celsius were excluded from the review.
Themes covered by studies eligible for review included inflammation, adipose tissue, blood circulation, the immune system, and oxidative stress.
Immersion in cold water has a great effect on the body and triggers a shock response such as a high heart rate.
Some studies have provided evidence that cardiovascular risk factors are indeed improved in cold-adapted swimmers. However, other studies show that the workload on the heart is still increasing.
The review provided insights into the positive links between swimming in cold water and brown adipose tissue (BAT), a type of ‘good’ body fat activated by the cold. BAT burns calories to maintain body temperature, unlike ‘bad’ white fat, which stores energy.
Exposure to cold in water or air also appears to increase adiponectin production by adipose tissue. This protein plays a key role in protecting against insulin resistance, diabetes, and other diseases.
According to the review, repeated cold water immersion during the winter months significantly increased insulin sensitivity and decreased insulin concentrations. This was for both inexperienced and experienced swimmers.
The authors note, however, that the profile of swimmers participating in the studies varied. They ranged from elite swimmers or deep-rooted winter bathers to those with no previous winter swimming experience.
Others were certainly not ice bathers, but used cold water immersion as a post-workout treat.
There is also a need for education about the health risks of diving into ice water, the authors say. These include the consequences of hypothermia and heart and lung problems often associated with shock from the cold.