Workouts rev up “feel good” brain chemicals that help block stress and pain

runners on treadmills inside gym.
Many runners look for the added benefit as the brain releases "feel good" chemicals during their workout. Some have a name for it- "the runner's high." (Mallory Paul)

By Adriana Fernandez

Mallory Paul exercises almost every day – and it’s not just because she works as a membership adviser at Equinox Fitness in The Loop. The Dallas native sees her morning cardio workout as a fitness ritual that also energizes feelings of self-confidence and helps her sleep at night.

Paul suffers from insomnia. The long and strenuous cardio exercise shortly after getting to work has become her alternative to taking sleeping pills, she said. Paul starts her mornings with a quick pre-workout breakfast and heads to the gym. She said she loves to either run on the treadmill or swim in the fitness center’s pool until she depletes her body’s energy and has cleared her mind.

“My body is exhausted in the best way possible. It’s a great feeling when I’m really tired from the workout,” Paul said.

The 23-year-old said that having her muscles exert lots of energy and work to their limits helps her sleep at night, especially because exercising helps her feel happier.

“Even though I may be running, I feel like I’ve taken weight and stress off my shoulders,” said Paul. “There’s a definitely a sort of high, a rush of adrenaline, a release of emotion and stress.”

What Paul described as a “high,” is the effect of a particular type of brain chemical our nervous system releases to help us cope with stress and pain and boost our mood, according to Robin Dunbar, a social and evolutionary researcher at Oxford University in England.

These “feel good” chemicals are called endorphins. When it comes to exercise, Dunbar said endorphins have the ability to buffer even muscle aches.

“It’s stress on the muscles predominantly that they are responding to,” said Dunbar. “They are extremely good painkillers, about 30 times more powerful than morphine.”

Endorphins are opiate-like chemicals released in the brain that can help relieve pain and provide euphoric feelings.

The release of endocannabinoids, another natural brain chemical, also plays a critical role inducing the feeling of the “high” after physical activity, according to a University of Heidelberg study.

Endocannabinoids are a natural chemical compound that activates the same brain receptors as marijuana to reduce pain, and ease anxiety, among other effects.

In the study, researchers measured anxiety and pain levels of two groups of mice, one of which was allowed to run on wheels while the other group remained mostly sedentary. The mice that ran showed lower levels of anxiety and pain, and high levels of endocannabinoids.

The group of mice that ran was then given drugs to block the release of either endorphins or endocannabinoids. When researchers suppressed the mice’s endorphin release, they still exhibited a decreased anxiety and pain. However, the opposite happened when endocannabinoids were blocked.

“The problem with endorphins is that they are very large molecules, and they don’t cross the brain-blood barrier so everything that is released in the brain, stays there,” Dunbar said.

The professor of evolutionary psychology explained many studies fail to properly record endorphin levels in our system because they are only found inside the brain and difficult to measure. Dunbar said it would involve painful extraction of cerebral spinal fluid to determine levels. He said these painful testing requirements are one of the reasons why endorphins are not studied so frequently.

However, he added that levels can also be traced with cerebral scans.

“It’s only the endorphins being released in the brain that have analgesic, opiate-like effects,” Dunbar said.

Photo at top: Many runners look for the added benefit as the brain releases “feel good” chemicals during their workout. Some have a name for it- “the runner’s high.” (Mallory Paul)