“Exercise helps everything!” That’s what ob-gyn Erica Cahill, MD, cohost of The V-Word podcast, told POPSUGAR when we asked why exercise can make menstrual cramps feel better. We agree — exercise is basically muscle-building magic — but what exactly is it about a workout that can ease period pain, in particular?

It’s a combination of two things, Dr. Cahill explained. On the one hand, exercise releases endorphins, chemicals that boost your mood and help you feel happier. Beyond that, Dr. Cahill explained that exercise also reduces your levels of cortisol, aka the hormone your body releases when you’re stressed. Cutting cortisol is big when you’re having cramps, Dr. Cahill said, because you’ll decrease inflammation, too.

What does inflammation have to do with cramps? As Jaime Knopman, MD, a reproductive endocrinologist and the director of fertility preservation at CCRM New York, told POPSUGAR in a previous interview, cramps are caused by the uterus contracting, like a muscle cramping up during exercise. Those contractions are necessary — that’s what expels the uterine lining — but the hormones that trigger them, she explained, also cause inflammation and pain. That’s why exercise, which helps to drop your cortisol levels and decrease inflammation, can be helpful.

Not that you’re always in the mood to exercise when it feels like your uterus is preparing to explode. If a workout is out of the question, you can try a heating pad or painkillers like ibuprofen. But if you can manage it, Dr. Cahill says, those natural chemical responses make exercise a great cramp remedy to try before, during, or after your period. Check out this trainer’s workout recommendations for every phase of your period to see if that exercise magic can make your cramps a little more manageable.