What do you think of when someone asks you to picture going on a long run? A runner’s high was described by the neuroscientist Arnold Mandell in the 1970’s as “Colours are bright and beautiful, water sparkles, clouds breathe, and my body, swimming, detaches from the Earth” (Hutchinson, 2019). This description isn’t the image that many people would picture when they think of having to run for hours at a time. The idea of long-distance running, along with many other endurance sports, seems to be a gruelling activity – how did Mandell describe such an idyllic scene?
The answer to this question is the concept of a runner’s high, characterized by an increase in mood, lost sense of time, positive thoughts associated with your run, or euphoria (Hicks et al., 2018). A runner’s high is thought to be caused by a combination of endorphins, which are the internal equivalent to morphine, and endocannabinoids, which are the endogenous equivalent to THC (University of Bonn, 2008). Recently, it has been shown that both of these chemicals are produced in an increased quantity after long periods of running (Hicks et al., 2018; Hutchinson, 2019).
A study performed by Hicks et al. (2018) studied microRNA’s present in the spit of runners both before and after a long run. This allowed them to determine which genes were being expressed at higher levels after the run (Hicks et al., 2018). Along with a questionnaire that determined which runners had experience a runner’s high, it was found that microRNA’s associated with endocannabinoid, endorphin, and GABA processing were increased after the run in patients that described characteristics of a runner’s high (Hicks et al., 2018). Additionally, those that had experienced a runner’s high showed more dilated pupils and a significant drop in core temperature, which interestingly, are both characteristics of using the psychoactive drug class benzodiazepine (Hutchinson, 2019). While this is yet another class of drug, it is just more evidence pointing towards a runner’s high being caused by multiple endogenous drug signalling pathways.
(Galdino et al., 2014)
In 2008, the idea that a runner’s high was caused by endorphins was first suggested. In a PET brain imaging scan performed before and after a run saw increased levels of endorphins released by certain areas of the brain after the run (University of Bonn, 2008). This was determined by using a competitive inhibitor of the opiate receptor, which was seen to bind less after the run. This indicates that the opiate receptors were already bound by endogenous molecules. While the idea that a runner’s high could be caused by endorphins had been suggested previously to this, this was the first time that it was substantiated (University of Bonn, 2008).
A significant application to this research is that exercise is being looked at as a potential treatment for those suffering from chronic pain. Endocannabinoids are known to reduce pain response in patients (Galdino et al., 2014; Watkins, 2018). With the other drug-like effects that are seen from a runner’s high, exercise could potentially reduce the need for as many pharmaceuticals to treat chronic pain. Alternatively, it could be used as a treatment alongside these pharmaceutical drugs. So perhaps the next time you’re feeling down or a little sore, the best fix may not be to curl up inside, but instead to go for a nice, long run!
Works Cited:
Galdino, G., Romero, T.R.L., Silva, J.F.P., Aguiar, D.C., de Paula, A.M., Cruz, J.S., Parrella, C., Piscitelli, F., Duarte, I.D., Di Marzo, V. and Perez, A.C., 2014. The endocannabinoid system mediates aerobic exercise-induced antinociception in rats. Neuropharmacology, 77, pp.313–324.
Hicks, S.D., Jacob, P., Perez, O., Baffuto, M., Gagnon, Z. and Middleton, F.A., 2018. The Transcriptional Signature of a Runner’s High. Medicine and Science in Sports and Exercise.
Hutchinson, A., 2019. This is what happens to your brain during runner’s high. The Globe and Mail. [online] 11 Jan. Available at: <https://www.theglobeandmail.com/life/health-and-fitness/article-this-is-what-happens-to-your-brain-during-runners-high/> [Accessed 14 Mar. 2019].
Skeze, 2016. Running, Runner, Long Distance. [Photograph] Available at: <https://pixabay.com/photos/running-runner-long-distance-1705716/> [Accessed 14 Mar. 2019].
University of Bonn, 2008. The myth of runner’s high revisited with brain imaging. American Association for the Advancement of Sciences. [online] 3 Mar. Available at: <https://www.eurekalert.org/pub_releases/2008-03/uob-tmo030308.php>.
Watkins, B.A., 2018. Endocannabinoids, exercise, pain, and a path to health with aging. Molecular Aspects of Medicine, 64, pp.68–78.