There is quite a lot of scientific evidence that regular vigorous exercise can protect you against mental illness, and can even be an effective treatment, for example of depression. There are probably a few reasons for this:
- Exercise causes the release of 'feel-good' brain chemicals known as endorphins.
- Exercise causes the release of a brain hormone called 'brain-derived neurotrophic factor' (BDNF) which stimulates the growth of new brain cells (neurones) and brain connections (synapses).
- Exercise also has good psychological effects, such as getting you out of the house and getting you active, going you a sense of achievement, and getting you interacting with other people (especially with team sports).