Two world-leading experts from the University of Portsmouth are available to offer advice and guidance on outdoor swimming as the weather improves.

While there are anecdotal claims of the mental and physical benefits of cold water swimming, world-leading experts say it also carries great risk if not done with caution. 

Professor Mike Tipton’s research in the Extreme Environments Laboratory at the University of Portsmouth has revealed the main problem with the passtime is cold water shock (CWI) – which peaks in water temperatures between 10-15⁰C.

CWI can affect anyone, regardless of whether they are strong swimmers or not, and increases the difficulty in getting out of the water. It is caused by a rapid fall in skin temperature and includes gasping, hyperventilation, release of stress hormones, hypertension and arrhythmias.

Professor Tipton said: “Just because we're seeing sunnier days, don't be fooled into thinking seas, lakes and rivers are already warm enough to swim without caution or consideration.

"We're already seeing reports of people getting into difficulty in the water, and the best way to prevent this trend from continuing is by raising awareness of the risks of cold water immersion and outline what people can do to swim outdoors safely."

A paper published in the British Journal of Sports Medicine outlines what people can do to mitigate any risks associated with CWI. These include taking a medical assessment before entering cold water, nominating a safety observer and agreeing to an emergency signal, and entering the water slowly and gradually.

Co-author, Dr Heather Massey, added: "We understand that there have been many reports in the news and on social media of the health benefits of outdoor swimming, which can lead to people wanting to try it themselves.

"We're still exploring if these claims are supported by science, but what we do know for sure is that people enjoy swimming, especially when the sun is shining."