What Is a "Runner's High?
The notion of a surge in endorphin levels resulting in a "runner's high" has been talked about for decades, but only in 2008 did the myth become fact. Researchers in Germany, lead by Dr. Henning Boecker, used positron emission tomography, or PET Scans, to confirm that exercise does, in fact, cause endorphins to be released in the brain. Endorphins are the brain’s naturally occurring opiates and are related to decreased pain perception and an increased sense of well-being. It's this flood of endorphins that results in mood changes, such as euphoria and the famed "runner's high."
Measuring Endorphins in Runner's Brains
The German scientists used PET scans to measure endorphin activity in the brains of 10 runners at rest and after a long-distance run.The runners received a PET scan before and after a two-hour run along with psychological testing. They compared the PET scan images to determine which areas of the brain had the most endorphin activity. The also asked the runners to rate their mood, including their level of euphoria. The reported feelings of euphoria were then compared to the changes in the endorphin levels in certain areas the brain.
Evidence for Increased Endorphin Levels and the Runner's High
The results of this study showed the following:- Endorphins were produced during exercise.
- The endorphins attached to receptors in the parts of the brain commonly associated with emotions (the limbic and prefrontal areas).
- The amount of endorphins produced in the brain matched the degree of the mood change reported by the runner. (i.e., as a runner described a greater euphoria and mood change, more endorphins were seen on his PET scan.)
The researchers' conclusion:
"Changes in central opioid receptor binding after 2 hours of long-distance running were identified preferentially in prefrontal and limbic/paralimbic brain regions. Specifically, the perceived levels of euphoria were inversely correlated with opioid binding in prefrontal/orbitofrontal cortices, the anterior cingulate cortex, bilateral insula, and parainsular cortex, along with temporoparietal regions."
While this study only looked at the role of endorphins on the runner's high, other experts are speculating that a variety of brain chemicals, including adrenaline, serotonin, dopamine and others, may contribute to these feelings of euphoria in exercisers. This research is just getting underway. The next study Dr. Boecker and his colleagues are planning is to study the pain perception in marathon runners and non-runners. They plan to compare reported pain perception with actual brain scans to look for chemical activity related to pain perception. They also intend to compare the effect of the intensity of the exercise on these findings.
Source
Boecker, H., Sprenger, T., Spilker, M.E., Henriksen, G., Koppenhoefer, M., Wagner, K.J., Valet, M., Berthele, A., Tolle, T.R. (2008). The Runner's High: Opioidergic Mechanisms in the Human Brain. Cerebral Cortex DOI: 10.1093/cercor/bhn013
