By Pat Anson, Editor

People with more friends and large social networks have a higher tolerance for pain, according to a new study by researchers at Oxford University.

Scientists believe that social bonding activities such as music, dancing and laughter activate the body’s endogenous opioid system, releasing natural endorphins that not only make you feel better when seeing friends, but can also relieve pain.

“Endorphins are part of our pain and pleasure circuitry -- they're our body's natural painkillers and also give us feelings of pleasure,” says Katerina Johnson, a doctoral student at Oxford University, who is studying whether differences in neurobiology can explain why some people have larger social networks than others.

“To test this theory, we relied on the fact that endorphin has a powerful pain-killing effect -- stronger even than morphine.”

Johnson and her colleagues enrolled 107 healthy young adults in a squatting exercise to test their tolerance for pain. Participants were told to squat against the wall with their knees bent at a 90° degree angle, and to hold that position and endure the discomfort for as long as possible.

Questionnaires were also completed by the participants to measure their personality traits and physical fitness, and to see how often they interacted with friends.

Not surprisingly, people who were more fit were able to hold the squatting position longer. But so did people with larger social networks.  

“Obviously we had to bear in mind that fitter individuals may be able to endure this physical pain test for a longer length of time.  However, even when we take this into account, our results show that pain tolerance still significantly predicts network size,” Johnson wrote in an email to Pain News Network.

An unexpected finding was that fitter people in the study tended to have smaller social networks.

“It may simply be a question of time -- individuals that spend more time exercising have less time to see their friends. However, there may be a more interesting explanation -- since both physical and social activities promote endorphin release, perhaps some people use exercise as an alternative means to get their 'endorphin rush' rather than socializing,” she said.

Since only healthy people participated in the study, Johnson admits her research may not apply well to chronic pain patients. But since many pain patients are disabled and unable to work or participate in many social activities, there could be some lessons to learn.

“When considering chronic pain, it seems like it may be a vicious circle whereby the more an individual is in pain, the less interested they are in interacting socially with others and their smaller social networks may in turn result in reduced activity of the endorphin system (thereby worsening their pain).  Perhaps also individuals that are genetically predisposed to reduced endorphin activity (and lower social motivation) are more likely to develop chronic pain conditions,” Johnson wrote.

“Another finding of our study was that individuals with smaller social networks tend to be more stressed, and stress is also thought to exacerbate pain.  However, clearly the underlying neurochemistry in pain responses is complex, though the endorphin system is heavily implicated in pain responses given its potent analgesic properties.”

The study findings are reported online in the journal Scientific Reports.