Feeling lonely can hit you where it hurts — all the way down to the cellular level, suggests new evidence.
Feeling socially isolated can have physiological consequences that could affect your life span, a new study found.
More specifically, the study authors, led by John T. Cacioppo, PhD, a loneliness expert at the University of Chicago, found that loneliness may lead to "fight-or-flight stress signaling," which might weaken the immune system.
Loneliness is hard to measure, so Dr. Cacioppo and colleagues studied humans and rhesus macaques in "perceived social isolation." For humans, feeling isolated is pretty straightforward. For the social primates, the macaques, it was a matter of whether they had been classified as socially isolated by their caretakers.
The lonely humans and lonely rhesus macaques showed reactions that could both weaken the immune system and promote inflammation. Chronic inflammation has been linked to many aspects of poor health, including an increased risk of cancer, bowel disease and heart disease.
Overall, compared to people and primates who weren't lonely, loneliness appeared to raise the risk of premature death (from any cause) by 14 percent, Dr. Cacioppo and team found.
If you needed another reason to go out and make some new friends, this may be it.
This study was published Nov. 23 in the Proceedings of the National Academy of Sciences.
The National Institutes of Health, John D. and Catherine T. MacArthur Foundation and John Templeton Foundation funded this research. The authors disclosed no conflicts of interest.