If you exercise regularly, then you know it exists. I’m talking about that post-workout rush of endorphins pouring over your brain and body to make you feel like you’re on top of the world.
The term “runner’s high” has infiltrated pop culture so much that we use it for that general feeling of well-being we get after a good bout of huffin’ and puffin’, whether it was running or not. We all know runner’s high isn’t exclusive to runners. It happens to the best and worst of us.
But are endorphins actually responsible for runner’s high? The existing body of literature isn’t enough to prove it. Research shows there may be no such thing as an endorphin-induced post-exercise high after all.
The Lowdown on Endorphins
Endorphins are feel-good chemicals produced in the hypothalamus and pituitary gland. They’re typically called your natural painkillers because they can block out feelings of pain and stress, such as the kind you get when you exercise.
They share a similar structure with the drug morphine. When the brain releases endorphins, the opioid receptors in the brain turn on. This creates a sort of foggy haze over your perception of pain so you don’t feel it so much.
Scientists first discovered endorphins 40 years ago, according to sport and exercise psychologist J. Kip Matthews speaking to CNN. This was in the 1970s, which was around the same time long-distance running first became a fitness trend. Yes, that was also the same time when people first began experiencing the wonderful feeling we now call runner’s high.
Somehow, people automatically began linking endorphins, aka natural opiates, to their happy feelings. Thus, the terms “runner’s high” and “endorphin junkie” were born.
In more recent years, scientists began to delve into the actual connection between endorphins and post-exercise happiness. They found out that while endorphin levels in the blood rose after exercise, endorphin levels in the brain remained the same.
More importantly, the amount of endorphins in the blood did not affect the amount of endorphins in the brain. Endorphin molecules in the blood cannot jump over the blood-brain barrier to transfer to the brain.
Do you see the connection here? For you to actually feel good as a result of exercise-induced endorphins, the endorphins have to be in the brain. Plus, some research shows you actually have to exercise for more than an hour to see a rise in endorphin levels in the blood.
This is where the endorphin theory of the not-so-mysterious runner’s high unravels by itself. So if it’s not your endorphins, what makes you happy when you exercise?
Your Natural Marijuana
Say hello to anandamide, what scientists believe is the real cause of runner’s high. Otherwise known as the bliss compound, anandamide is an endocannabinoid, which mimics the effects of, yes, you guessed it, the cannabis plant.
That’s right. You have your own natural stash of marijuana inside you—and many experts think it’s what makes you happy after working out.
Research shows that anandamide levels in the blood increases during and after exercise. But unlike endorphins, anandamide in the blood can cross the blood-brain barrier and penetrate the brain. This produces the euphoric, pain-free feeling we now call runner’s high.
Anandamide also contributes to happiness in another, indirect way. This chemical also leads to the production of Brain Derived Neurotrophic Factor (BDNF). In English, BDNF is a protein that repairs and repairs brain cells, also called neurons.
Years ago, it was thought that humans stopped producing neurons as we grow older. That’s not true. Even adult brains can continue to grow through a process called neurogenesis, or simply, the creation of new neurons. This leads to new learning experiences that allows us to train our brains to be happier.
Anandamide plays an indirect role in neurogenesis by inducing the production of BDNF.
Meet the Others: GABA, Serotonin, Dopamine and Norepinephrine
There’s more to your runner’s high than anandamide alone. Several other brain chemicals work to boost your happy feelings after exercise. These are: GABA, serotonin, dopamine, and norepinephrine.
GABA, short for gamma Aminobutyric Acid, is your brain’s natural Xanax. It prevents you from jumping around in overenthusiasm as your excitable new neurons created with the help of BDNF fire around inside your head. It’s what gives you the feelings of calmness and peace of mind post-exercise, as though no trouble in the world can ever ruffle your feathers.
Another one of these happy chemicals is serotonin, which is known to be directly related to exercise. In a study published in the journal Neuropsychopharmacology, researchers demonstrate how physical activity induces the production and release of serotonin.
They saw that exercise doesn’t just increase the amount of serotonin, it also increases the rate at which it is released. In other words, you don’t just get more serotonin, you get more serotonin faster.
Serotonin also stimulates the production of tryptophan, an amino acid that is essential in creating even more serotonin. It’s a virtuous circle, one that goes on and on to boost your mood and lift your spirits after exercise.
Along with serotonin is dopamine, also known as the motivation molecule. Dopamine is a neurotransmitter produced from the amino acid tyrosine. It’s what pushes you to go after something you want, but it’s also what causes addictions in people who keep wanting more than what they had.
If you’re smart, you’d know better to boost your dopamine levels not through drugs, sex, and rock n’ roll but through exercise. A single, half-hour session won’t probably boost your dopamine, but consistent, regular exercise will raise your dopamine receptors. And if your genes detect this increase, they will respond by producing more dopamine in the long run.
Over time, your motivation to exercise will increase thanks to a dopamine boost, which will again produce more dopamine to make you want to exercise more. It’s a healthy “addiction” that provides positive results for your mental and physical well-being.
Lastly, there’s norepinephrine, also known as noradrenaline. Norepinephrine is a modulator that regulates other brain chemicals directly linked to that post-workout high.
The American Psychological Association says around half of all the norepinephrine produced in your brain is found in the locus coeruleus, a region that links all other regions related to stress and emotional response.
In other words, norepinephrine isn’t about directly causing happiness after exercise. It works on the big picture by linking all the other parts of the brain that have a hand at producing runner’s high.
“What appears to be happening is that exercise affords the body an opportunity to practice responding to stress, streamlining the communication between the systems involved in the stress response,” says Matthews. “The less active we become, the more challenged we are in dealing with stress.”
You might think, “Yeah, yeah. It’s not the endorphins. It’s GABA, serotonin, dopamine, and norepinephrine. So what?”
Well, the more you understand how the chemicals in your brain work, the better you can take advantage of them. Exercise doesn’t only help you lose weight and gain muscle. Perhaps more importantly, it produces positive effects in your brain—the kind that improve your mental health and boost your quality of life.
Most of us look at exercise as a pain in the butt, and that’s why most of us don’t like to exercise, even if we want to fit into that pair of old jeans from college or a swimsuit.
And that’s why it’s always so hard for people to get up off the couch and start moving—because instead of looking at the immediate rewards of exercise, we look at the far-off benefits that will only come in some faraway future.
If you want to exercise right here, right now, then you have to think about what you’re gonna get right here, right now. Sure, you’ll get a little bit of pain, a little bit of discomfort. But soon all that’s’ going to fade away, thanks to a quick shot of anandamide, and GABA, and serotonin, and dopamine, and norepinephrine, and will give way to post-exercise high. Nothing can bring you immediate happiness as much as exercise can.