All these studies fail to account for the relapsing / remitting nature of depression in many people; they don't establish any causal link (are people better because they exercise, or are they exercising because they're better?), the blinding is lousy, the controls are lousy, etc etc.
As soon as you run a well controlled properly blinded study you find very little effect for exercise as a treatment for depression.
No they have not. Well run meta analysis fail to find any benefit of exercise as a treatment for depression.
https://www.cochrane.org/CD004366/DEPRESSN_exercise-for-depr...
All these studies fail to account for the relapsing / remitting nature of depression in many people; they don't establish any causal link (are people better because they exercise, or are they exercising because they're better?), the blinding is lousy, the controls are lousy, etc etc.
As soon as you run a well controlled properly blinded study you find very little effect for exercise as a treatment for depression.