Have you got friends that like to take a refreshing (well more like freezing) dip in the ocean on Boxing Day? Or are you one of those people yourself? Well, you might be on to something: taking a dip in cold water may reduce the risk of disorders like diabetes and may cut body fat in men, according to a new review.
Cold-water bathing and swimming have become popular hobbies in recent years. This increase in popularity also comes with many anecdotal benefits from the people who partake in this pastime – including health benefits and increased libido.
In a recent paper, researchers investigated 104 studies that highlighted any effects of cold-water swimming. The team excluded studies where water temperatures were greater than 20°C (68°F), participants wore wet suits, or cold-water immersion was accidental. The studies that were included looked at a range of topics, such as the immune system, oxidative stress, adipose tissue, inflammation, and blood circulation.
Typically, during the initial cold water immersion, the human body will experience a triggered shock response, resulting in an elevated heart rate. There are conflicting views from different studies on the cardiovascular benefits, some suggested that people who partake in the hobby have reduced cardiovascular risk factors. While some studies indicate that the workload on the heart is still increased.
Studies found positive links between cold water swimming and brown adipose tissue – cold-activated "good" body fat that burns calories to maintain body temperature. This is different to the energy-storing white fat. Some studies revealed that exposure to the cold can increase adipose tissue production of adiponectin. This is a protein that helps protect against diabetes, insulin resistance, and other diseases. For experienced and inexperienced swimmers, taking a dip during winter can increase insulin sensitivity and decrease insulin concentration, the review found.
Overall, however, the review was found to be inconclusive on the overall health benefits. This is because the studies included often involved a very small number of participants, just one gender, a range of swimming experience, or used cold-water immersion in different ways (for example as a hobby or as a post-exercise treatment). There were also variables in terms of the water, such as the salt composition and the water temperature. The studies also didn’t identify if those who swam regularly were generally more naturally healthy than those who did not.
“From this review, it is clear that there is increasing scientific support that voluntary exposure to cold water may have some beneficial health effects,” Lead author James Mercer said in a statement.
“Many of the studies demonstrated significant effects of cold-water immersion on various physiological and biochemical parameters. But the question as to whether these are beneficial or not for health is difficult to assess.
“Based on the results from this review, many of the health benefits claimed from regular cold exposure may not be causal. Instead, they may be explained by other factors including an active lifestyle, trained stress handling, social interactions, as well as a positive mindset.
“Without further conclusive studies, the topic will continue to be a subject of debate.”
Please note, if you decide to go for a chilly dip this winter, you need to educate yourself beforehand on hypothermia and other issues that may occur from the shock of the cold.
The study is published in the International Journal of Circumpolar Health.