The term “runner’s high” is familiar to most Americans, a label for the euphoria experienced by athletes like long distance runners, cyclists, and swimmers who engage in strenuous exercise. It was coined in the United States during the running trend of the 1970s after researchers discovered opiate receptors in the human brain. One study identified runner’s high as “a subjective sense of well-being some humans experience after prolonged exercise.”
For decades, the effect of runner’s high was credited solely to endorphin (β-endorphin), an analgesic (pain killing) chemical produced by the body that is categorized as an “opioid neuropeptide” and is produced by the Central Nervous System (CNS) and pituitary gland. In fact, the word “endorphin” literally means “endogenous [internally produced] morphine.”
However, multiple studies spanning decades have indicated that, while endorphin may play a role in runner’s high, the effect is more likely produced by anandamide, an endocannabinoid and neurotransmitter that has been proven to interact synergistically with phytocannabinoids such as THC and CBD from plants like cannabis.
One of the major reasons for this is the fact that endorphins do not actually enter the brain, instead binding only with receptors on the surface — while cannabinoids like anandamide pass through the blood-brain barrier to enter this crucial and sensitive organ.
A 2003 study conducted in the United States at the Georgia Institute of Technology and the University of California (Irvine) and published in the journal NeuroReport discovered that men who exercised for one hour experienced considerably higher levels of the cannabinoid anandamide. The study also, importantly, concluded that it as anandamide that was causing the euphoria called runner’s high. This is notable because it was the first study to counter the idea that a runner’s high is produced by high levels of endorphins.
Investigators concluded that the human body produces its own cannabinoids as a means of dealing with prolonged pain and other bodily stresses during moderate or intense exercise, such as that experienced by endurance athletes. Said Arne Dietrich, one of the study’s researchers:
“No other study has ever considered this possibility, which is why the results are so significant.”
A more recent study supports this theory. In 2015, researchers published a report in the journal Proceedings of the National Academy of Sciences that also indicated the cause of runner’s high to be anandamide. Possibly more significant, when endorphins were thought to cause runner’s high, it was understood that the opioid receptors that bind with endorphins are on the surface of the brain, allowing them simply to block pain impulses from reaching the organ.
Anandamide binds with the same cannabinoid receptors within the brain and CNS as cannabinoids from cannabis. This study revealed that anandamide binds with CB1 receptors in the brain and CB1 and CB2 receptors in “peripheral” zones outside the brain, like the CNS and immune system. Concluded the researchers:
“We thus show for the first time to our knowledge that cannabinoid receptors are crucial for main aspects of a runner’s high.”
These two research studies, conducted on both humans and rodents (both of which have an endocannabinoid system; in fact, all mammals feature one), reveal that it is the endocannabinoid anandamide — not endorphin — that produces the effect known as runner’s high. This research sheds additional light on the overall role of the endocannabinoid system and how it interacts with the CNS and immune system to produce health-giving benefits.
More Research Needed
It is theorized that anandamide may play a role in helping those with psychological ailments like depression and PTSD. If the mechanism that causes runner’s high can be better understood, some of the underlying chemicals — be they derived from a plant like cannabis or produced internally by the human body — may play a role in therapeutic approaches designed to target specific ailments involving mood or mental disturbance.
However, until cannabis is removed from Schedule I of the Controlled Substances Act, it will continue to be regarded as possessing zero medicinal value and little research will be conducted into its potential to treat a variety of conditions and diseases. As long as the official stance of the United States government is to ignore the medical benefits of cannabis and block research (even methamphetamines and cocaine are officially considered safer than cannabis and found under Schedule II), ignorance will pervade and the full benefits of therapeutic molecules like anandamide will not be fully understood.
This post was originally published on February 23, 2016, it was updated on October 5, 2017.