Runner's High Revisited

Runner's high: scientists come closer to unraveling the mystery.

Posted May 20, 2008

Other researchers have found the pleasure boost produced by the experience so strong that orgasm is the occasional result.

Much of what we know about Runner’s High first emerged in the early 70s, when scientists decided that ‘in-the-zone’ feeling was a by product of endogenous—meaning internal to the body—opioids called endorphins. These chemicals kill pain and produce pleasure much like exogenous—meaning external to the body—opioids like morphine, opium and heroin.

There are at least 20 different endogenous opioids and most are not completely understood, but we do know that the analgesic power of the body’s principle endorphin, released during times of stress, can be a hundred times more powerful than morphine.

While this theory is mighty tempting to believe in, the relationship between runner’s high and endorphins has become something of a contentious topic. The biggest problem is that endorphins are large molecules, too large to penetrate the blood-brain barrier. Meaning, while the effects of runner’s high share a great deal in common with endorphins, the brain’s protective mechanisms make this an unlikely possibility. So unlikely that in 2002, Huda Akil, a University of Michigan endorphin researcher and the then-president of the Society for Neuroscience said, “this endorphins-in-runners is a total fantasy in pop culture.”

Things changed a bit in 2004, when then Georgia Tech (now at American University in Beirut) neuroscientist Arne Deitrich fingered anandamine—a tiny fatty acid that works as the body’s own version of THC (the psychoactive chemical in marijuana) as the chemical responsible. There are good reasons for this. Not only did Deitrich find large amounts of the chemical in young men after exercise, but anandamine’s properties include not only pain relief and pleasure stimulation, but an openness to experience, an increased appreciation of nature and a boost in empathy. Three other experiences which have been anecdotally associated with runner’s high. Even better, anandamine is a tiny molecule, small enough to have no problems penetrating the blood-brain barrier.

Well, it’s six years later, and Dr. Akil has recanted. What changed was recent research done by neuroscientists at the Technische Universitart Munchen and the University of Bonn, both in Germany, used PET scans to inspect the brains of ten athletes before and after a two-hour run. What they discovered was endorphins, a lot of endorphins floating around their subject’s brains.

Specifically, the found a lot of activity in the prefrontal and limbic regions—two places known to play a great role in emotional processing. They also realized, because of that blood-brain problem, that anandamine was acting as the trigger mechanism for this endorphin release.

Researchers are beginning to act as if this whole puzzle has finally been solved, but there’s a bunch of anecdotal evidence still to be explained. For example, time dilation—that feeling that time is slowing down to a miniscule pace—which often accompanies that in-the-zone feeling has not been accounted for.

There may be good reason for this. Research done by Cleveland Clinic neuroscientist Stephen Rao has shown that time dilation is a product of the neurochemical dopamine.

Unfortunately, the difficulty with doing runner’s high studies that include a test for dopamine is risk. As fellow blogger Greg Berns discovered, the brain produces dopamine primarily in response to risk-taking and, unfortunately, risk-taking is a difficult condition to control inside a laboratory environment.

Hopefully, that puzzle will be solved soon, but until then the greatest feeling on earth is only available the old-fashiond way: through blood, sweat and tears.