Winter swimming has attracted a growing number of aficionados in Finland over the last few years, with municipalities and associations opening more ice-free swimming spots with changing facilities and sometimes a sauna.
Many of those who regularly take the plunge attribute various benefits to the practice.
The Finnish Institute of Occupational Health, which has studied the effects of cold temperatures on health, responded to Yle about some claims and widely-held beliefs surrounding cold-water swimming.
According to the institute's chief researcher, Sirkka Rissanen, plenty of global research data on the effects of cold on health has been collected over the past century, including studies into winter swimming.
"Cold has the same effect regardless of whether it's air or water, but water conducts heat 25 times more efficiently than air of the same temperature. So water is fast-acting," she explained.
Rissanen added that research information will become more detailed as new imaging methods become available that enable scientists to study humans at the cellular level.
Five statements about cold-water swimming
Rissanen responded to the following claims about cold-water swimming and its health effects:
1. Cold-water swimming is suitable for anyone
In principle, yes. An adult and basically healthy person can get into cold water. However, if you have heart disease or high blood pressure, for example, you should consult a doctor before starting cold-water swimming.
2. Cold-water swimming relieves stress and improves sleep quality
Yes, it can reduce stress, and experienced winter swimmers report that they also get a feeling of relaxation.
In cold-water swimming, a counter-reaction takes place: going into the water is a stress factor for the body, so the secretion of stress hormones increases. However, winter swimmers feel that they "leave their stress behind in the water", when the feeling of well-being, the secretion of pleasure hormones, and the feelings of empowerment increase after leaving the water.
Relaxation and reduced stress also improve the quality of sleep. If the body and mind are in good condition, the quality of sleep also improves.
3. Cold-water swimming relieves colds and aches
Yes. The body toughens up when exposed to cold. Cold adaptation stimulates and enhances the immune system. That is why practitioners seem to catch fewer colds and flus.
In the cold, cortisol is secreted into the body, which relieves pain. Cold-water swimming can help with pain, especially if there is inflammation or rheumatism in the joints, but it can also help with muscle pain.
4. Cold-water swimming helps you lose weight
You won't lose weight directly, but brown fat can increase during cold exposure. Its increase and activation as a result of regular cold exposure can also affect your weight.
Unlike white fat, brown fat produces heat. It then consumes energy and can thus reduce weight.
For example, for a newborn infant, brown fat is the only heat production mechanism. Slim people have more brown fat than heavier people, who in turn have more insulating white fat.
5. You can even jump into cold water
Preferably not, at least not so that your head sinks underwater.
When you jump in suddenly, you get quite a cold shock. When cold water hits the face, a yawning effect may occur as breathing becomes more frequent. You have to be careful not to draw water into your lungs, so there is a risk of drowning.
The cold suddenly impacting the face and head area can be too harsh an experience for the heart, as the sympathetic and its opposite, the parasympathetic nervous system, are activated at the same time. This can cause arrhythmia.
The blood vessels in the head area do not constrict, unlike those in the fingers, skin and other parts of the body. When blood vessels contract, heat loss decreases. Cold exposure increases blood pressure.
Back in the day
In the 1940s and 1950s, Helsinki's winter swimmers organised demonstrations that included jumping headfirst into a hole in the ice. They aimed to show the health benefits of year-round swimming.
You can watch a film clip from the Yle archives below.
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