Mental health advocates have been quietly recommending exercise to combat depression and anxiety for years. Now, thanks to a recent study, we have data showing just how effective running can be at treating depression— while also improving overall health. According to this study (and others before it), aerobic exercise is on par with commonly prescribed antidepressant medications, but has few negative side effects and considerable added benefits.

Often, people see exercise, sleep, or nutrition changes as less effective than pharmacologiocal treatment. Something so commonplace can’t possibly actually work, right? Give me the good stuff, doc. Don’t hold out on me.

But the numbers don’t bear that out. Changing behavior does change health outcomes, significantly. The data are clear.

So why hasn’t exercise been embraced as a first-line treatment for these common mental health problems?