Reader's question: Does winter swimming really bring health benefits?
The current cold snap has often brought the hardy out for a spot of winter swimming, if social media is anything to go by.
One reader of ERR's Novaator portal inquired whether the practice really does bolster the immune system and provide other health benefits, a question which Doctor Liis Puis was happy to answer.
"In everyday language, people like to use the expression 'boosting the immune system,' but in reality the goal of any activity should not be an excessive immune response, which the word 'boosting' might imply. That is because overreacting can actually lead to autoimmune diseases – a situation where the body attacks itself and its own organs," Puis explained.
This means that, from a medical standpoint, it would be better to use the expression "supporting the immune system."
So, does winter swimming help support the functioning of the immune system? The doctor said that a number of physiological reactions are seen in the body in response to swimming in particularly cold water – whose temperatures will only be slightly above, or even at, freezing point (saltwater's freezing point is a little lower than that of freshwater).
This is because the body finds itself unexpectedly plunged, literally, into a situation which it must quickly react to, in order to protect itself.
"In fact, there are no high-quality clinical studies on winter swimming and immune system function. It has indeed been suggested that certain reactive changes occur in the cells and molecules, that serve to drive our immune system in response to cold, either in the short term or somewhat longer term. However, there are no large-scale, high-quality studies that have examined and proven that those who practice winter swimming have fewer infections," the doctor noted.
There are nonetheless several hypotheses which could support the claim that winter swimming is beneficial, which are:
- Exposure to cold leads to certain changes in immune system cells and molecules.
- With regular exposure to cold, the body may better adapt to similar types of stress.
- The posited short-term anti-inflammatory effect of cold water.
- The impact of winter swimming on people's overall sense of well-being and their mood – winter and ice hole swimming does not appear to be a quiet or solitary activity – which in turn can be an important part of immune system functioning.
To sum up, it is not currently known whether those who regularly practice winter swimming suffer from fewer infections, as there are no solid studies on the topic.
According to Puis, we can only speculate about possible mechanisms supporting this hypothesis, based on known physiological mechanisms and observational data.
As well as the possible health benefits of winter swimming, there are very real health and safety risks, and these should perhaps be uppermost when considering whether to go for a dip in the icy water.
"It is certainly vital to emphasize that winter swimming is not suitable for everyone. People with chronic illnesses should definitely consult their doctor before trying it. Likewise, even a healthy person should not recklessly enter cold water without preparation and without following the rules, without knowing and assessing the potential risks," Puis concluded.
More advice and safety tips on winter swimming is here.
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Editor: Andrew Whyte. Sandra Saar
