Training for a marathon can cause an interesting state of mind. Even half marathon training or 10km training can
lead to the fabled Runner’s High. Is it a just a perception or is there actually something going on inside the brain.
First of all, what is this wondrous thing? Runner’s High has been described as a state of bliss achieved during and immediately following prolonged and intense exercise. It can be an extremely powerful, emotional experience.
The Cannabinoid Hypothesis
Arne Dietrich, Ph.D. and 2:52 marathoner, knew about a brain receptor site that was shown to be the receptor for THC, the active ingredient in marijuana that produces a different kind of high. The site was named the cannabinoid receptor. As the body does not develop receptors without good reason, Dietrich figured there must be a chemical naturally produced by the body so the receptor had something to receive. The natural chemical was discovered in 1992, several years after the discovery of the receptor. The chemical, called Anandamide, is very similar to THC and produces comfortable feelings of relaxation and reduction of pain similarly described by runners and marijuana users.
Anandamide, it was found, also dilates blood vessels and the bronchial tubes in lungs. Both of these physical adaptations are beneficial to the long distance runner.
Dr. Dietrich was a corresponding author in a study released in the 2003 NeuroReport in which is reported the first evidence that exercise of moderate intensity activates the endocannabinoid system. (http://www.harford.de/arne/articles/NeuroReport.pdf)
Runner’s High, that euphoric state reported by some to be not unlike the re-living of some college days, may have a scientific backing.
All I know, is that every once in a while, on a long run, I couldn’t care less about science, or training schedules, or much of anything… I’m just out running. And I’m quite alright with that!