4. According to Harvard psychiatrist John J.Raety， M.d.， coauthor of a book on psychological disorders called Shadow Syndromes， a single workout can raise your brain's levels of antidepressant chemicals， such as dopamine， serotonin and norepinephrine.
5. If you are feeling down， exercise may help pick you up. Although researchers disagree on this issue， one review of past studies found that long-term exercise， especially when it includes long-lasting， strenuous training sessions， has about as much of an effect on depression as psychotherapy. ( Of course， this doesn't mean you shouldn't seek therapy. If you believe you may be suffering from depression， the first thing to do is to consult a mental-health professional. )
6. Working out helps you deal with stress in your job， relationships or any area of life—possibly because exercise is a form of stress itself and helps condition your body to deal with it. When Australian researchers compared people who did 30 minutes of aerobic exercise three times a week to those who practiced progressive-relaxation techniques， they found that the former group responded better to acute stress and had lower blood pressure.
7. Even a little exercise can make you think less anxiously， Studies have shown that any amount of exercise， from a brisk 10 minute walk to an intense aerobics or weight-lifting session， seems to decrease feelings of anxiety.
8. Aerobic exercise may make you think better. Over time， cardio exercise (coupled with a healthful diet) improves the flow of blood that carries oxygen and nutrients to your brain.
9. Working out regularly may make you smarter now and lessen the possibility that you'll lose brain function as you age. According to a recent animal study at the University of Illinois， exercise can actually help the brain develop new cells.
10. In several studies， regular weight training or aerobic exercise was shown to improve the quality and duration of sleep. Naturally， this can make you less fatigued and be able to function better during the day.