How Do Exercise Endorphins Work, Exactly?

Well, why would anyone work out if they felt pain the whole time?


Let’s run down the list of cliched experiences that make us, as humans, feel physically good, shall we? There’s massages — check. There’s also, well, sex. Masturbation, too, for that matter. A nice, long stretch feels pretty damn nice, and heck, even a solid hug does the body good. 

And then there’s exercise. 

As far as I’m concerned, the greatest lie the devil ever told is that exercise makes you feel good. When I exercise — about once every month — my body is a wreck. If I run, my knees hurt; if I lift, I’m as sore as the dickens for days afterward.

So why, then, do people say that exercise makes you feel good? For that, you can thank endorphins.

Endorphins are hormones, secreted from a small, bean-shaped gland next to your brain, which make you feel, well, good. Harvard University refers to them as “the body’s natural painkillers,” and the Mayo Clinic calls them “mood elevators.” Under normal circumstances, endorphins are produced by the pituitary gland in a response to pain, binding to your body’s opioid receptors and, in turn, blocking the neurotransmitters that make you say “Ow!”

The release of endorphins also triggers something else: The production of dopamine, the hormone responsible for pleasure. Pleasure, in case it’s not clear, is literally the definition of feeling good.

So what, then, do endorphins have to do with exercise? Thanks to hundreds of thousands of years of evolution, our bodies have evolved to produce endorphins at even a hint of physical activity. That’s because, as sports psychologist Dr. J. Kip Matthews explained to, endorphins are a stress response, and since exercise causes physiological stress, endorphins are released to mitigate that stress. And, in doing so, pain is blocked, dopamine is produced and athletes feel a sense of euphoria — a feeling commonly referred to by endurance athletes as a “runner’s high.”

And so, if you’re a frequent exerciser, if you ever feel like you’re getting addicted to going to the gym, or wonder why an hour-long sesh pumping iron or running on the treadmill makes you feel surprisingly good — unlike me, whose levels of pain far exceed anything endorphins could ever overcome — blame it on your hormones.