will sooner or later have to find time for illness.
Edward Stanley, Earl of Derby, 1873. The Conduct of Life.
Runners High
Runners high (or runner’s high) is real. Perhaps you’ve felt it: A sense of euphoria, bliss, calm, and well-being that comes over you after intense exercise. But what causes it?
Amateurs and experts agree. Prolonged exercise raises people’s spirits. They usually attribute it to runners high, without further explanation. Scientists have been trying to find the mechanism behind this effect for decades. Many believe that the body’s own opioids, so-called endorphins, are the cause. These natural painkillers produced by the body were discovered around 1975.
One problem with this theory involving endorphins is the blood-brain barrier. These molecules are too large to pass from the bloodstream into the brain, so the endorphin hypothesis doesn’t seem to hold up. But researchers in Germany have suggested that endorphins are also produced within the brain. Using PET scan brain imaging techniques, they have analyzed the binding of endorphins to receptors within certain regions of the brain. There is evidence that the perception of pain in conditions like rheumatoid arthritis is influenced by the binding of endorphins with these receptors. In one study, higher levels of endorphins were found in cerebrospinal fluid after patients underwent acupuncture.
Recently an alternative explanation for runners high has been proposed. Under certain conditions the body creates its own cannabinoids, similar to an active ingredient in marijuana. These endocannabinoids are smaller molecules that can pass through the blood-brain barrier to reach receptor sites in the brain.
Our bodies produce endorphins and endocannabinoids. Perhaps neuroscientists will one day determine which system is the true source of runners high. Or maybe they will discover another explanation involving both endorphins and endocannibinoids, along with other hormones such as epinephrine, serotonin, and dopamine.
Think of it this way: Exercise causes runners high! Whether this involves endorphins or endocannabinoids or some other mechanism, the benefits of exercise are indisputable. It makes you feel better. It makes you healthier. And it makes you look better!
