We need to be careful with what they're saying.

> Scientists have also known that exercise seems to cushion against depression. Working out somehow makes people and animals emotionally resilient,

Many people translate this to mean "exercise can treat depression".

Here's one meta analysis that suggests exercise is a weak treatment for depression.

http://summaries.cochrane.org/CD004366/DEPRESSN_exercise-for...

> Exercise is moderately more effective than no therapy for reducing symptoms of depression.

But also

> The reviewers also note that when only high-quality studies were included, the difference between exercise and no therapy is less conclusive.

> Exercise is no more effective than antidepressants for reducing symptoms of depression, although this conclusion is based on a small number of studies.

> Exercise is no more effective than psychological therapies for reducing symptoms of depression, although this conclusion is based on small number of studies.

I'd like to see better research that controls for things like social networks (a person might be more likely to go jogging with friends than alone, for example) and other confounding factors.