Exercise can help people with mild depression. I would not depend on it to treat severe mood problems. But even there, exercise provides many important health benefits.

Regular activity makes us feel better about ourselves. People who exercise regularly report being more cheerful and less stressed. They sleep better and have a better appetite.

Many people feel good while they exercise and right afterward. But exercise also changes the brain in positive and lasting ways. Brain cells get healthier and make stronger connections. So with regular exercise, mood improvements can really last.

We don’t know what the right “dose” is. There is no single type or amount of exercise that is ideal. We do know it is most important to do it regularly.

A good start is 30 minutes of aerobic activity three or four times a week. You should start to breathe more rapidly and get a light sweat. You can increase the intensity and length of workouts from there.

Choose a program that you can stick with. That is much more important than trying to do more than you can manage.

It may be especially difficult for depressed people to keep it going. Some people get easily frustrated if their mood doesn’t improve right away. Others have trouble finding the will to continue. If that happens, try standard treatments such as medicine and psychotherapy. They are very effective. If those treatments start working, it won’t hurt to add exercise back into the mix.