Hugging, like maintaining a healthy diet and exercise regimen, may boost the body’s immune system and protect from infection, Carnegie Mellon University researchers have found.

Previous studies have shown that people who have unresolved conflicts in their relationships are less able to fight off cold viruses, and that people who receive social support are partly protected from the effects of stress on psychological states like depression and anxiety. Study authors hypothesized that hugging may also offer these health benefits because it is a form of social support.

"We tested whether perceptions of social support are equally effective in protecting us from stress-induced susceptibility to infection and also whether receiving hugs might partially account for those feelings of support and themselves protect a person against infection,” study author Sheldon Cohen, a psychology professor at Carnegie Mellon, said in a news release.

Researchers assessed perceived support among about 400 healthy adults by providing a questionnaire. They drew data regarding frequencies of interpersonal conflicts and receiving hugs from telephone interviews that were conducted on 14 consecutive evenings. Study participants were then exposed to a common cold virus, and monitored and quarantined to assess infection and signs of illness, according to the news release.

Study authors discovered that perceived social support reduced the risk of infection associated with experiencing conflicts— and that hugs accounted for one-third of this protective effect. Regardless of whether a participant reported having an interpersonal conflict, greater perceived social support and more frequent hugs helped mitigate cold symptoms.

"This suggests that being hugged by a trusted person may act as an effective means of conveying support and that increasing the frequency of hugs might be an effective means of reducing the deleterious effects of stress," Cohen said in the news release. "The apparent protective effect of hugs may be attributable to the physical contact itself or to hugging being a behavioral indicator of support and intimacy."

"Either way, those who receive more hugs are somewhat more protected from infection," Cohen added.