...but do risks mean it should be classed an extreme sport?

COLD-WATER swimming should be treated as an extreme sport, experts have warned.

The number who have died in the UK after open-water swimming rose from 34 to 61 between 2018 and 2021, they say.

And the coastguard reported a 53 per cent increase in call-outs associated with the hobby.

But scientists fear people are not aware of the dangers. They say participants can go into cold shock, which is caused by a rapid fall in skin temperature and can lead to gasping, the release of stress hormones and abnormal heart rhythms. Professor Mike Tipton, of Portsmouth University, said: ‘Cold shock and the loss of control of breathing can result in drowning.’

Colleague Dr Heather Massey, who is co-leading a trial into coldwater swimming and depression, said: ‘Outdoor swimming is an extreme sport. It is very important you think before you swim. ’