Friendships are a key indicator of happiness. They improve physical and mental health, and can even help prolong life. A study published this week has discovered that people with a large circle of friends also have a higher pain tolerance.
Researchers from the University of Oxford tested the theory that we feel happy after hanging out with friends partly because social interactions trigger endorphin activity, which leads to positive emotions. Endorphins have a strong pain-killing effect—“stronger even than morphine,” says co-author Katerina Johnson, experimental psychology doctoral student in a statement. So the researchers used pain tolerance as a way of assessing endorphin activity.
The study, published in Scientific Reports, used a non-invasive physical pain test, asking 101 healthy adults to squat against a wall with knees at a 90° angle and a straight back for as long as possible. Participants also filled in questionnaires about their two closest friendship circles—people they spoke to every week and those they spoke to monthly. The study found that those with larger social networks could endure the pain for longer, and that the network of people contacted monthly was a particularly strong indicator of pain tolerance.
This suggests that people with more friends have a higher level of endorphins, which act as natural painkillers.
The researchers acknowledge limits of their study: using pain tolerance as an indicator of endorphins, rather than directly monitoring endorphin activity. And they say more research is needed on the causality between networks of friends and pain tolerance.
But Johnson adds that studying friendship is important for understanding human health. “In this digital era, deficiencies in our social interactions may be one of the overlooked factors contributing to the declining health of our modern society,” she says.