Outdoor swims have become a fixture of the Christmas period for many, with communal festive dips into Britain’s icy waters a growing seasonal tradition.
However, warnings about the dangers of swimming in cold water have grown after two men in swimming trunks, drying themselves near freezing waters in Salford Quays, were condemned as “utterly reckless”, said the BBC.
Salford City Councillor Barbara Bentham said if the men were not “trained to swim in cold water then they are lucky to be alive”.
She told the broadcaster the council had issued many warnings that open water was cold even on the hottest days of the year. “I cannot begin to imagine how cold the water must have been and I hope this was just a one-off moment of madness,” she added.
Cold-water swimming enthusiasts speak of numerous health benefits but others warn of risks and dangers.
Pro: immersion is a stress buster
Cold-water swimming is an “instant mood booster”, said Woman & Home. It cited a study carried out by scientists in Prague, which found that cold-water immersion can boost dopamine levels by 530%. A 24-year-old woman who had suffered from depression and anxiety since she was 17 was able to stop taking her medication after a trial of weekly cold-water swimming.
A separate study, published in the British Medical Journal, found that open-water swimming can be used to treat some cases of depression.
Con: risk of heart danger
Cold-water swimming “could spell trouble” for people with heart issues, said Harvard Medical School’s Massimo Ferrigno, because the “shock of cold water” shifts “even more blood to the chest, taxing the heart”. Being in colder water “may provoke irregular heart rhythms”, agreed the British Heart Foundation.
It can also “lead to a lower heart rate and higher blood pressure”, wrote Ferrigno, adding that “some people respond so strongly to cold water that just putting their face in a bowl of cool water can make them pass out from a low heart rate.”
Pro: metabolism booster
Want to burn off your Christmas weight gain? Regular cold-water swimming may lead to weight loss. Swimming in cold water “causes your body to react in order to produce more heat and maintain your core temperature”, said Circle-One, which will “increase your metabolism, burning fat in order to keep warm”.
A Scandinavian study of men who went winter swimming two or three times a week found that they use the equivalent of around “500 extra calories per 24 hours on average compared to other people”, reported the Daily Mail.
Con: underwater obstacles
Wild waters will obviously not be as clean and clear as swimming pools. “Weeds can wrap around swimmers’ legs, causing them to get into difficulty, even drown”, said travel writer Kathryn Burrington, adding that “hidden rocks and other objects beneath the water can also be dangerous”.
Surfers Against Sewage warned last month that wild swimmers are “increasingly getting sick from sewage pumped into rivers and seas”, noted the BBC. The charity received 720 sickness reports over the last year, up from 286 people the previous year and 124 in 2019-20.
Pro: immunity booster
Swimming in cold water is believed to be beneficial to the immune system because it helps to boost the white blood cell count when the body is forced to react to changing conditions.
For instance, a study carried out by Czech scientists linked cold-water immersion to invigorating the immune system and an increase in white blood cell count and antioxidant levels.
Con: hypothermia risk
There is a danger of hypothermia, which sets in when the body temperature drops to below 35°C and can be fatal.
Hypothermia can “catch you unawares”, said Outdoor Swimmer and “not everyone shows the same symptoms”. You can “often still be able to swim, feed and answer questions despite it, and never complain of being cold or feel excessively cold”.
“Even in really cold water it takes at least half an hour for you to become hypothermic,” said Practical Boat Owner, but “when you get out” it “becomes a more likely risk”, so it’s important to warm up as fast as you can.