Grab a pair of goggles and jump in. Swimming is, quite simply, about the best exercise you can do – whether you're getting fit, staying fit or really going for the burn.
Swimming is great for the heart and lungs, and puts very little stress on your muscles, joints and bones. With a few sessions of swimming a week you could reduce your blood pressure, strengthen your stomach and back, and burn off as many as 600 calories an hour.
Even highly-tuned athletes and runners like to alternate between swimming and running because it means they can exercise more often without injuring themselves.
There are Active Nation sessions and courses for all ages, and all abilities.