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Role of the Endocannabinoid System in “Runner’s High”

Marathon runners typically speak of a blissful state that they reach after a moderate training session with a fair duration of running. They attribute it to having decreased pain, decreased anxiety, and feeling an overall sense of calm. This state is referred to as a “Runner’s High” and the Endocannabinoid system of the body causes it.

What is Runner’s High

After running for approximately thirty minutes at around 80 percent of one’s heart rate maximum, a runner will feel calm, comfortable, bliss, and decreased pain sensation. The experienced has been described as euphoric by marathon runners.

How does Runner’s High Work

Upon sufficient aerobic exercise such as running, the human body begins secreting increasing levels of endorphins and the cannabinoid anandamide. When the body begins secreting anandamide(AEA) and endorphins into the blood they make their way towards the brain. But, unlike anandamide, endorphins are too large to pass through the blood brain barrier. Fortunately, endorphins are also synthesized in the brain. According to research, once anandamide makes its way into the brain it is able to bind to CB receptors on GABAergic neurons and will move throughout the periphery and CNS binding to CB1 & CB2 receptors to give multiple effects to the runner. Endorphins were believed to be the sole reason for why this state of “Runner’s High” was experienced. But, not anymore.

What is the Role of the Endocannabinoid System in Runner’s High

Research conducted in 2015 by Johannes Fuss and company, examined the phenomenon that is runner’s high and how AEA and endorphins were implicated. In their animal study, they found that intact CB1 receptor activation on forebrain GABAergic neurons produced anxiolytic effects, and pain reduction was activated via AEA binding in the periphery of the body via both CB1 and CB2 receptors. Research used antagonists of both AEA, and Endorphins and tested the mice for anxiety related behavior(dark & light test) pain sensitivity on a hot plate, and sedation.

Because pain, anxiety, and survival are related, it is believed that the bodies of organisms such as humans, evolved to develop their own endocannabinoid systems for many reasons. But, in this case, the role of the ECS in “Runner’s high” is to mitigate the pain sensation, and anxiety felt during prolonged exercise. It is a means of reducing the stress an individual is experiencing through their body and mind. As a result, the runner will be able to exercise for a longer period of time once the euphoric feeling paired with decreased sensation of pain.

Can endocannabinoid deficiency affect Runner’s high

In the study conducted by Johannes Fuss and company, when they utilized antagonists of both AEA and Endorphins, they found that the mice experienced more anxiety in the dark & light test, increased pain sensitivity to the hot plate and decreased running time because it was suspected that due to no reward of feeling euphoria, the mice simply didn’t want to run as much as before.

One caveat is that Mice ran an average of 3 miles a day to produce a firm “Runner’s High” in the statistics of the study. This is a long distance for mice and therefore because humans are not mice, it is implied that humans would need to run a much greater distance to really experience a significant “Runner’s High”. With that being said, if there were endocannabinoid deficiency of the secretion of anandamide to the brain and the periphery of the body then exercise would be a much more difficult task to complete than before.

Hence, a deficiency of the ECS would yield similar results in a human. More anxiety. More pain. Less bliss and less motivation to exercise due to a decreased “euphoric” feeling during running and thereafter. The ECS has a role in a plethora of processes in the body and before it was believed that endorphins(opioid-like) were the sole proprietors of the “Runner’s high”. But, that is no longer the case.