We all know about the health benefits of swimming. It offers a great workout for the body – it builds endurance, muscle strength and cardiovascular fitness. If you don't mind getting wet, it can be fun too. But who would enjoy swimming in water that's ice cold? Well, many people are taking the plunge, based on evidence that it can actually be good for us.

Cold-water swimming – sometimes called wild swimming – involves swimming in natural areas including ponds, rivers and the sea. Jumping in gives a short sharp shock to the body, but many participants say they get used to it. A cold dip might wake you up, but research has found it can have much bigger benefits than that for your body and mind. As well as being good exercise, spending time outdoors and by water improves wellbeing.

There is much evidence, mostly anecdotal, that suggests cold-water swimming has cured certain health conditions. One man who suffered constant pain after surgery claimed he was cured by taking a plunge in cold open water. And another swimmer, Sandria Simons, told the BBC “the immersion of your body in cold, salt water, just feeling like you're at one with nature if you like, just feels amazing.”

But what is it that people are gaining from this chilly experience? Doctors say getting into cold water evokes a stress response, but the more you do it, your reaction to stress is reduced. It's also thought to have a strong anti-inflammatory effect. But there are bigger benefits to this stress-reducing exercise. Some experts believe cold-water swimming helps ‘cross-adaptation', where one form of stress prepares the body for another. For example, it also helps reduce the stress of exercising at high altitude.

So, if you're convinced that this is for you, take advice: approach it with caution, swim with a friend, and maybe start in the summer, when the water temperatures are higher!