Brain Imaging Explores the Myth of the Runner's High

Medical specialists and most runners agree that prolonged jogging raises people's spirits. Moreover, many believe that the body's own opioids, so-called endorphins, are the cause of this. However, this has never been proved until now. Utilizing imaging technology, researchers have succeeded in demonstrating the existence of an "endorphin-driven runner's high.”

In an imaging study, researchers from the Technische Universität München (TUM; Germany) and the University of Bonn (Germany) were able to show, for the first time, increased release of endorphins in specific areas of the athletes' brains during a two-hour jogging session. Their results are also relevant for patients suffering from chronic pain, because the body's own opiates are generated in areas of the brain, which are involved in the suppression of pain. The researchers showed that jogging not only makes one "high,” but can also relieve pain. The results of the study were published in the online Advance Access issue published on February 21, 2008, in the journal Cerebral Cortex.

Endurance sports have long been seen as reducing stress, relieving anxiety, enhancing moods, and decreasing the perception of pain. The high that accompanies jogging even led to the creation of its own term, runner's high. Yet, the cause of these positive effects on the senses was not clear until now. The most popular theory was and still is the "endorphin hypothesis,” which claimed that there was increased production of the body's own opioids in the brain. However, until now, direct proof of this theory could not be substantiated; for technical reasons, it was a constant source of controversial discussions in scientific circles. The result was that the myth of "runner's high through endorphins” lived on.

Scientists from the fields of nuclear medicine, neurology, and anesthesia at the Technische Universität München and the University of Bonn have now subjected the endorphin theory to closer evaluation. Ten athletes were scanned before and after a two-hour long-distance run using positron emission tomography (PET) imaging. For this they used the radioactive substance [18F]diprenorphine ([18F]FDPN), which binds to the opiate receptors in the brain and hence competes with endorphins.

"The more endorphins are produced in the athlete's brain, the more opiate receptors are blocked," stated Prof. Henning Boecker, who coordinated the research at TUM and who is now in charge of the Functional Neuroimaging Group at the department of radiology, University Hospital Bonn. "Respectively, the opioid receptor binding of the [18F]FDPN decreases, since there is a direct competition between endorphins in the brain and the injected ligand.”

By comparing the images before and after two hours of long distance running the researchers could demonstrate a significantly decreased binding of the [18F]FDPN-ligand. This is a strong argument in favor of an increased production of the body's own opioids while doing long-distance running.

"We could validate for the first time an endorphin driven runner's high and identify the affected brain areas,” stated Prof. Boecker. "It's interesting to see that the affected brain areas were preferentially located in prefrontal and limbic brain regions which are known to play a key role in emotional processing. Moreover, we observed a significant increase of the euphoria and happiness ratings compared to the ratings before the running exercise.”

Prof. Thomas Tölle, who for several years has been head of a research group called Functional Imaging of Pain at TUM, added, "Our evaluations show that the more intensively the high is experienced, the lower the binding of [18F]FDPN was in the PET scan. And this means that the ratings of euphoria and happiness correlated directly with the release of the endorphins. The fact that the endorphins are also released in areas of the brain that are at the center of the suppression of pain was not quite unexpected, but even this proof was missing. Now we hope that these images will also impress our pain patients and will motivate them to take up sports training within their available limits.”


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Technische Universität München
University of Bonn