Lead author Lisa Jaremka, a postdoctoral fellow at the Institute for Behavioral Medicine Research at Ohio State University, and colleagues found people who were more lonely showed signs of elevated latent herpes virus reactivation and produced more inflammation-related proteins in response to acute stress than people who felt more socially connected.
Reactivation of a latent herpes virus is known to be associated with stress, suggesting loneliness functions as a chronic stressor that triggers a poorly controlled immune response.
"It is clear from previous research that poor-quality relationships are linked to a number of health problems, including premature mortality and all sorts of other very serious health conditions. And people who are lonely clearly feel like they are in poor-quality relationships," Jaremka said in a statement.
"One reason this type of research is important is to understand how loneliness and relationships broadly affect health. The more we understand about the process, the more potential there is to counter those negative effects -- to perhaps intervene," Jaremka said.
The findings, presented at the Society for Personality and Social Psychology annual meeting in New Orleans, were based on a series of studies conducted with two populations: a healthy group of overweight middle-aged adults and a group of breast cancer survivors.