Exercising just 20 minutes three times a week has been shown in clinical studies to reduce depression symptoms as effectively as antidepressant medication in some patients.

In a real clinical study, people who exercised for 16 weeks ended up with depression symptoms just as improved as people who took sertraline, a common antidepressant medication. Not slightly worse. Not ‘pretty close.’ Equal. That’s a big deal, and it’s come up repeatedly in peer-reviewed medical research.

How much exercise are we talking? According to research published in medical journals, a prescription of about 20 minutes a day, three times a week, at moderate intensity is enough to significantly reduce depression symptoms. That’s roughly an hour a week total. You don’t need to run a marathon or join a fancy gym — moderate intensity means you’re working but could still hold a conversation.

Here’s the science behind why it works: exercise affects your brain chemistry. It temporarily boosts levels of serotonin, the same chemical that many antidepressants target. It also increases something called BDNF — basically a protein that helps your brain cells stay healthy and communicate better. Interestingly, when exercise is combined with antidepressants, BDNF levels rise in as little as two days, compared to about two weeks with medication alone.

Important caveat: researchers are still working to fully understand exactly how exercise fights depression, and these findings apply to ‘some patients’ — not everyone. Depression is complicated and different for different people. Exercise is a powerful tool, but it’s not a guaranteed replacement for medication or therapy for everyone.

The single most important takeaway: if you’re feeling low, consistently depressed, or just mentally sluggish, moving your body three times a week for even 20 minutes isn’t just advice your PE teacher would give — it’s something clinical studies back up hard. Start small. It counts.