Lakes, rivers, the sea… if you live in the UK, any outdoor, non-heated swimming is cold-water swimming. I do it because I enjoy being outside and it’s something I’ve always done.


Lots of people report positive effects from doing it

There’s lots of anecdotal evidence. People say cold-water swimming can help with depression, pain and migraines. Some menopausal women find a decrease in the severity or number of hot flushes.

These personal experiences are important, but we lack the scientific studies to back them up. This is starting to change. We want to know who benefits from cold-water swimming, what the effects are and what the underlying mechanisms are.

What else could it help?

One study, from Cambridge University, hinted that cold-water swimming might help stave off dementia. Compared with members of a Tai Chi club, winter swimmers at London’s unheated Parliament Hill Lido were found to have higher levels of a protein that helps protect against neural degeneration.

Cold water has a big impact

The gasping for air, the rise in heart rate and the increase in blood pressure… these are all parts of the cold shock response from entering cold water. This can be dangerous for people with certain underlying health conditions. It’s also possible to breathe water into your lungs and drown. In 2020 in the UK, around 250 people died from accidental immersion in cold water.

Need to know...

  1. If you have any medical concerns, check with your GP before you start cold-water swimming.
  2. Get in slowly to adjust to the cold, but make sure you can get out easily before the cold makes doing so difficult.
  3. Getting out early is better than staying in too long. And bring a towel, warm clothes and a hot drink.

Swim safe

If you have any medical issues, check with your GP before you start cold-water swimming. Never swim alone. Find local groups to swim with. They’re friendly and full of local knowledge.

Don’t forget your swimsuit

In the height of summer, all you need is a swimming costume, a towel and maybe some flip flops. If you want to spend longer in the water or are swimming in winter, you might wear a wetsuit or neoprene gloves. It doesn’t have to be expensive and will also help to keep you warm after you leave the water.

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Get in slowly

Before you get in, work out how you’ll get out. If the exit is tricky, make sure to give yourself enough time. Then when you’re ready, get into the water slowly. This minimises the cold shock response. If you can’t ease in gently, splash water on your legs, then arms, then torso and then get in. Take a few minutes to get over the cold shock response before you start to swim. If you can talk in full sentences, you have full control of your breathing.

Make it a quick dip

Unless you’re an experienced cold-water swimmer, keep it brief. Five to ten minutes is plenty. We don’t know the optimum time, temperature or frequency of cold-water swimming needed to reap any potential benefits, but we do know that you’ll fatigue more quickly in cold water. So if you’re not enjoying it, get out.

Get out before you’re ready to go

Exit the water knowing that you’d like to have stayed in longer. Get dry, dressed and warm. It’s always a good idea to bring of flask of something warm to hold on to and drink afterwards.

In time, science may confirm the health benefits of cold-water swimming, but for now, just enjoy it and be safe.

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Helen Pilcher
Helen PilcherScience writer, presenter and performer.

Helen Pilcher is a tea-drinking, biscuit-nibbling science and comedy writer, with a PhD in cell biology.