Exercise can be a very effective way to treat depression. So why don’t American doctors prescribe it?

Here’s the most important thing I learned while writing a book on running and mental health: In clinical studies, regular aerobic exercise is as effective as antidepressants in reducing symptoms of mild to moderate depression. And that’s not just because moving might help you get into shape and feel better about yourself. Exercise actually causes the same structural changes to the brain as antidepressants—neuroplasticity, or creating new neural pathways, and growth in the hippocampus, a part of the brain that’s generally shrunken in people with depression.