The runner's high is a subjective euphoric feeling that can happen both during and immediately after exercise. While physical exertion often causes discomfort and even pain, the lucky few also get a pronounced feeling of delight. When you run, you're flooding your body and blood with endorphins. As the body's self-produced opiates, endorphins produce a variety of chemical changes that are often interpreted as pleasure and joy. Endorphins are a natural pain reliever, which helps you to run for longer and feel better when you're finished. ; ; ;
Contrary to popular belief, however, the chemical nature of the runner's high is not entirely down to endorphins. New research points to another type of molecule, with endocannabinoids also thought to be responsible. While both endorphins and endocannabinoids are completely safe and natural, the former shares similarities with drugs like codeine and heroin, and the latter is related to marijuana. While endorphins do play a role, it turns out they may not be responsible for the feelings many people associate with the runner's high.
A new study by researchers at the University of Heidelberg medical school has made a strong case for endocannabinoids. When mice were studied after running, they were found to have elevated levels of both endorphins and endocannabinoids. They were observed to be less sensitive to pain and less anxious after running. They were more tranquil and spent more time in the light areas of their cage instead of retreating to the dark corners. However, when the mice were given drugs to block their endocannabinoid receptors, they were no longer relaxed, just as anxious, and very sensitive to pain. Interestingly, this reversal did not happen when opioid receptors were blocked. ; ;
While they may not be responsible for the runner's high, according to a separate study by the University of Missouri, natural opioids do play a part when it comes to exercise motivation. While opioid abuse can obviously lead to lack of motivation, natural endorphin release does provide some get-up-and-go. With many similarities between healthy exercise and not-so-healthy drug use, both of these studies could play a role in the development of effective drug addiction treatment programs. ;
According to Greg Ruegsegger, lead author of the University of Missouri paper, "when we chemically activated their mu-opioid receptors, those rats drastically reduced their amounts of activity... Since exercise and addiction to substances follow this same chemical process in the brain, it stands to reason that activating these receptors in people with dangerous addictions could provide the same rewards they are craving without the use of dangerous drugs or alcohol."