Why we should all be taking cold showers

In his new podcast, Just One Thing, Dr Michael Mosley takes a chilly dive into the science of cold water to find out how it could help your mood, brain, immune system and heart.

Cold water stresses the body

Throughout evolution, your body has developed a stress response which automatically kicks in when under threat to keep your body alive. It’s a really neat and efficient design – it means everything gets kick-started at the same time, with effects all around your body from your brain to your toes. And your body sees cold water as a big threat – it effectively activates your body’s primal stress response causing you to hyperventilate and your heart rate to shoot up; and the blood vessels around your body start doing all sorts of shape-shifting tricks, from rapidly and drastically decreasing in size in a matter of seconds in some parts of your body, to doubling in size in others. It’s a whole orchestra of responses that put your body into gear for survival – all the while, giving you quite the thrill!

Cold water: A great source of short-term stress

But we’ve all been taught that stress is a bad thing, so why would you want your body to go into this survival state, when it could be enjoying the nice relaxing effects of a cup of tea and a quiet morning? Well, chronic stress certainly isn’t good for you, but a growing body of research is suggesting that a short burst, at the right dose, can actually be beneficial!

A little bit of stress is good

In recent years, a huge body of research has shown that a short period of stress can actually be a good thing. This holds true for a whole range of situations that scientists have looked at, from doing public speaking, to trying out mental arithmetic under pressure – and it can lead to a variety of benefits. As cold water is one of the most effective ways to create short-term stress across your whole body, it’s this response that they think triggers the benefits.

Right now scientists are looking at how cold water can affect everything from immune response to stress hormones, to fatty deposits that clog up your arteries. It’s a relatively new area of research, but so far the results have been promising.

Cold water and your immune system

There is growing evidence that winter swimmers are more resistant to certain illnesses and infections, experiencing them less frequently and more mildly. For example, cold water swimmers seem to have fewer upper respiratory tract infections. And scientists think it might be the cold water rather than the swimming that’s giving the benefit.

One study found that having 30-second cold showers every morning for 60 days could decrease the number of sick days by 30%. So a cold shower might be all you need!

Cold water, mood and inflammation

After cold water immersions, there have been reports of increased dopamine, serotonin and b-endorphin levels, consistent with the “post-swim high” so many cold-water enthusiasts report.

There have also been case studies where cold water swimming has been shown to help reduce use of antidepressants. And one particularly exciting area of research is looking at how cold habituation decreases inflammatory responses over time – so could potentially help with conditions from rheumatism to depression.

How long lasting are the effects?

It’s early days in terms of the research, but it looks as if cold water treatment could be surprisingly powerful and long lasting. One study found that just six immersions in cold water produced a physiological effect which could still be seen over a year later.

It might be worth trying a short blast of cold water in the shower to see if it works for you!

To find out more, listen to Just One Thing: Cold Shower.