A new study has found that endocannabinoids, a chemical responsible for feel good effect among runners is similar to the effect of smoking marijuana. The study debunks earlier findings which say endorphins were responsible for runner’s high.
Researchers found that endorphins are indeed produced while exercising, but it has a smaller effect in the feeling of euphoria during sustained exercise or running. Endorphins do not cross brain’s blood-barrier, so they weren’t causing runner’s high. However, endocannabinoids can pass directly from blood to brain, making the body relaxed — similar to the effect of marijuana use.
“Recent evidence suggests that endocannbinoids also may play a role,” wrote researchers in the study.
Dr. Johnaness Fuss, senior author and his team conducted three experiments, to find the effect of the chemical in runners. Rats were placed in a running wheel, and each rat ran for about 10km/day for 12 hours each day. Fuss said that they are really motivated to run; there are strong biological processes motivating these mice to run in running wheels, therefor they are a good model to study why humans are motivated to exercise.
During the experiments, rats were grouped into two: one were in the wheel inside the cages and others did not run. Researchers studied the pain and anxiety levels during each run, and the running rats showed higher levels of endocannabinoids in their blood. Researchers determined if which chemicals was causing the feeling of euphoria by blocking the receptors of endorphins and endocannabinoids. When endocannabinoids were blocked, rats showed signs of fatigue.
Since 2003, several studies have been conducted to determine if endocannabinoids ere connected to runner’s high, but minimizing the effect of endorphins gave a stronger evidence for the study. Study authors concluded that endocannabiloids were responsible for the good effect during long runs. The study has been detailed in the recent edition of Proceedings of the National Academy of Sciences (PNAS).
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