Mental function is improved by physical activity, and conversely a lack of physical activity can lead to a decrease in blood supply to the brain, which is already evident in the aging process.

When the body is exercised it induces the growth of capillaries, or small blood vessels, in the brain which in turn enables nutrients to reach the neurons.

The other really important function of physical activity is to promote deep sleep. This is important because it is during the deep sleep that the brain rebalances the hormones and brain chemicals, consolidates memory, and gets us ready for the next day's activities.

If you haven't exercised regularly up until now it's not too late to start. Begin by visiting your doctor to make sure you are physically able to exercise, or start with a light exercise regime and gradually build up.