It is the most famous quote from the movie Legally Blonde (which is making the rounds again now that it is available on Netflix): “Exercise gives you endorphins. Endorphins make you happy. Happy people just don’t shoot their husbands. They just don’t.”
It’s what most people think about when they think about the whole “working out is good for your mental health” advice bit.
Endorphins: The Cheerleaders in Your Brain
While it would be easy to chalk the simpleness of the quote up to Hollywood trying to push a plot point, there is real science there. Exercise really does give you endorphins and endorphins really do help improve your mental health. That runner’s high you’ve heard so much about? That’s an endorphin rush. Here’s how it works.
When you start to exercise, especially when the increased movement raises your heart rate, your brain interprets this as a “fight or flight” type stress response and does two things. It releases a protein called Brain-Derived Neurotropic Factor (BDNF) and releases hormones called endorphins.
BDNF is protective and pushes a sort of “reset” button in our memories which helps calm us down and allows us to think more clearly. The release of BDNF is why it is easier to think clearly when you are exercising.
Endorphins, in addition to triggering positive feelings throughout your body, help minimize the discomfort you feel during (and often immediately) after exercising. They bind to the same neuron receptors that pain medicines attach themselves too, which is why their effect is often similar.
Beyond the release of endorphins, your brain releases serotonin and a few other “happy making” chemicals. And, of course, as you move around, your heart pumps harder and faster, which increases the flow of blood to your brain, which helps increase your brain’s functionality.