Everyone says that exercise is good for you, mentally as well as physically. It does you good and makes you feel good. As a tool for lifting mood and dampening anxiety, for many people it's as effective as medication. We all know this. And yet...

Exercising works on several levels. There's the calming effect of regular deep breathing and repetitive movement - jogging being a good example. There's the sense of achievement that comes with overcoming the easy option of giving up. There's the natural endorphin high which is stimulated by strenuous exercise. Finally, there's the meditative effect of concentrating on something outside yourself, like a tennis ball, which can quieten negative self-talk. (The best books on this aspect of sport are by Timothy Gallwey, author of the highly influential Inner Game of Tennis.)

So why not start improving the exercise quotient of your life. How about a walk. Vigorous walking has been shown to be almost as effective as jogging for enhancing CV fitness, by doing just three 30 minute sessions a week.