Triathlon Daily

Runner’s high: the idea that endorphins released during endurance activities cause a person to feel exceptionally happy— euphoric, even. Is it fact or fiction? Truth or fabrication? Some people swear they get it. Others shrug off the notion incredulously. Despite an air of mystery surrounding the phenomenon, others still cross their fingers and hold out hope that they might eventually feel it. Now researchers are starting to obtain results that might one day earn this seemingly mythical experience a place among generally accepted truths. Using positron emission tomography (PET) scans, researchers in Germany have taken the first steps to illustrating how what happens in the brain during an endurance run might relate to the feeling of runner’s high. According to their paper published last month in the journal Cerebral Cortex, endurance running led to changes in opioid binding in certain parts of the brain and corresponded to feelings of euphoria in the runners. In the study, researchers from the Technical University Munich and the University of Bonn looked at 10 trained male runners who had experienced runner’s high in the past and were fit enough to complete a 2-hour endurance run. Each runner was injected with a radioactive ligand that would bind to opioid receptors in the brain and had their brain scanned twice: once in a resting state and once 30 minutes after a 2-hour, 21km run. Their moods were also analyzed at these times using Visual Analog Mood Scales (VAMS). The results of the PET scans showed that after running there were fewer opioid receptors available in certain parts of the brain for the PET ligand to bind to, indicating these receptors were already bound by an opioid released during the run. This decreased receptor availability showed up in areas of the brain that are understood to play a part in emotional processing and occurred alongside a significant increase in feelings of happiness and euphoria. This suggests there is a link between endorphin binding in certain parts of the brain and the feelings of runner’s high, which seems to fit with common theories thus far. As this was a pilot study, there is much work to be done to confirm the mechanism behind these results. Currently the team, as led by Professor Henning Boecker, is looking at the effects of endurance training on pain processing. Perhaps one day soon scientists will get to the heart—or should I say the brain?—of the runner’s high and all it entails. Release of endorphins after endurance training: five consecutive brain slices. The brain areas in which body-own opioids are released and bound after long-distance running are most strongly visible in regions a, b and c, which play an elementary role in emotional processing. The subjective level of euphoria in the investigated runners was closely related to the amount of endorphins released and bound in these areas.