Image source: Maaniemi, Tero. (2209, January 21). Avanto [Photograph]. Flickr. https://images.app.goo.gl/eTq5MHDbrLbhDVq67
By: Quinnlyn Boyle
The thought of going for a swim may seem crazy as winter approaches, but for some, the dropping temperatures indicate the start of polar plunge season. A quick dip in the frigid Canadian waters sends a shock through the body–but upon returning to shore, this is replaced by a sweeping refreshing sense of calm. Is this activity, seen as reckless by some, actually beneficial to one’s physical or mental health.
Research seems to suggest it is. More specifically, an occasional quick swim in cold water reduces stress levels. This is because brief cold water immersions are acute stressors. Repeated exposure to these short-term stressors triggers adaptive physiological mechanisms that have beneficial health effects–including metabolic changes that allow more food to be digested and insulatory and hypothermic changes, which reduce heat loss by lowering skin temperature and internal temperature, respectively (1, 2).
Once out of the water, the transition from a cold to warm environment increases blood circulation. Upon initial exposure to a cold environment, an individual’s blood vessels will contract, a process known as vasoconstriction. However, returning to a warm environment triggers vasodilation, where blood vessels expand (3). In the context of a cold plunge, this increases blood circulation to a level higher than before the swim, which in turn increases the flow of nutrients and oxygen to the body (3, 4).
Many studies suggest that individuals can reap significant general well-being effects from winter swimming (5). One study followed a group of winter swimmers and a group of non-swimmers (the control), assessing fatigue at the start and end of a four month period. The swimmers experienced a significant decrease in fatigue–and therefore an increase in energy–compared to the non-swimmers, who showed a stable level of fatigue throughout the period. The results also suggest a decrease in tension for the swimmers (5).
The body can also experience a slight increase in blood flow while actively immersed in cold water if one is in a warm environment before the plunge. This is known as cooling-induced vasodilation. It occurs after five to ten minutes of cold water immersion. However, this increase in blood flow only lasts until the body’s internal temperature drops below the baseline (4).
In addition to the cold water aspect, the act of swimming itself is beneficial to one’s physical and mental health. Physical activity releases mood-boosting dopamine and endorphins, which can result in a “post swim high”–a very similar feeling to the post-run feeling. Studies have shown that after a swim or a run, individuals reportedly experience less depression and anxiety (6, 7). This makes swimming a great alternative for those who are not particularly inclined to go for a run.
Despite all of these benefits, there is still risk in cold-water swimming. A sudden drop in body temperature can cause hypothermia (3). Individuals with pre-existing conditions like high blood pressure and heart conditions are more susceptible to the risks of cold water immersion, such as hypothermia or a cold shock response (3). These risks can be managed through a gradual introduction to cold water immersion, starting with higher temperatures and shorter immersion periods.
It appears a quick polar swim can be beneficial for an individual’s health in a multitude of ways, as long as it is performed carefully. So this winter semester, be sure to pack a swimsuit alongside your hats and scarves!
The Abstract 