Depression effects almost everyone at some point during their life. I put this page under obesity because there's a strong connection between obesity, over eating and depression.
The Mayo Clinic websitesays "Anything that gets you off the couch and moving is exercise that can help improve your mood."
The book "The Origin of Everyday Moods" describes how even a short 10 minute walk is one of the most effective and healthful ways to improve mood and alertness.
This study showed that aerobic exercise was as affective as drugs at treating MDD or "Major Depressive Disorder".
Another study found that exercise not only made people feel better, it also helped prevent the blues from returning.
Weight lifting had the same effects as aerobics at getting and keeping people happier.
Finally, this study showed that exercise may actually cause the growth of new brain cells linked to depression in older adults.The study speculates that increases in serotonin (our feel good neurotransmitter), beta endorphins (our brain's own "opium") and "growth factors" produced by exercise may be the cause.