mental health is definitely related to physical health. although it might not _cure_ your problems, the pros of being healthy vs the cons of a sedentary / not physically active lifestyle by itself outwieghs the other.

I don't think it's a meme, it's just that people seem to be realising it's beneficial as of late

Better than the meme of someone saying they sometimes can't concentrate or suffer from some other extremely common problem, and hordes of people respond with, "you obviously have ADHD."

I suck at physical exercise. And I hate it. I still believe these people have a point though.

With that said – exercise is one tool in the toolbox. It can’t and shouldn’t be the only tool.

It's a cliché but it's true.