That happy, invincible feeling you get when you’re floating through the air at the peak of a workout?
You’ve probably heard that it’s something called endorphins that your body produced during prolonged exercise. That idea, which has been around since the ’80s, is based on the theory that these chemicals interact with receptors in the brain to reduce your perception of pain and some thought they may also give you that euphoric boost.
A new study published last week in the Proceedings of the National Academy of Sciences challenges that notion and puts forth a different theory: That such a “high” could be due to a different substance called endocannabinoids.
Endocannabinoids can basically be thought of as the body’s self-produced marijuana and, like cannabis, can impact a wide range of physiological processes, including appetite, pain, memory and mood.
The new research was only in mice, so it’s unclear how it will apply to humans, but what the researchers found is almost certainly intriguing enough to inspire follow-up studies.
Researchers from the Central Institute of Mental Health of the University of Heidelberg took mice and gave them running wheels. They found that after the runs, the mice were less anxious and tolerated pain better.
Then they used drugs to block the animals’ endocannabinoid system. The results were striking. The animals were as anxious after running as before running and more sensitive to pain.
“We thus show for the first time to our knowledge that cannabinoid receptors are crucial for main aspects of a runner’s high,” the researchers wrote.
There’s been a lot of other interesting research on the subject of runner’s high recently. In August, scientists at the University of Montreal published their work on a different animal study involving the hormone leptin, which is nicknamed the “satiety hormone.”
Leptin, which regulates energy stores, signals to the body when it has enough fuel and energy. The researchers said it’s possible that when you are in the middle of a workout, your leptin levels may fall, and this could “send a hunger signal to the brain’s pleasure center to generate the rewarding effects of running.”
