Exercise doesn't protect against adolescent depression

It's known that exercise may benefit people with depression, but less is known about its ability to protect against depressive symptoms in adolescence. Some of the problems with research into exercise involve how to measure it, as self‐reports are notoriously misleading. Researchers at the University of Cambridge in England investigated the link between objectively measured exercise and ensuing depression over a three‐year period of adolescence. They found that there was no connection between the two — exercise neither increased nor decreased the likelihood of depressive symptoms.