Exercise can improve mood and reduce risk of depression by a number of mechanisms including: 1) improving fitness and muscle tone, 2) reducing excess fat, 3) improving blood flow to the brain, 4) improving sleep and 5) increasing the blood levels of chemicals called endorphins.
A large study of 3,645 young Australian women (aged 18 to 45 years) reported that those who engaged in 3.5 hours of more a week of recreational exercise had rates of depression about 30% lower than among women who exercised less than 40 minutes per week. Women who watched television for more than 14 hours a week had significantly higher rates of depression than those women who watched less television. This research by Teychenne et al. is now in Press in Health Education Research.
Get active to reduce risk of depression! People should pick an exercise(s) they enjoy and stick with it regularly. Brisk walking, jogging, bicycling (regular or stationary), swimming, weight lifting, exercise class, dancing, tennis and golf (walking the course) are all excellent forms of exercise. Vigorous forms of house, yard or farm work are also good exercise. Oftentimes working out in a group, or with friends or relatives will make sticking to a regular exercise program much easier.