Although plenty of studies have found that lonely people are more likely to suffer from a chronic health problem, researchers from the University of Surrey are among the first to work out the physiological effects of being alone.
Loneliness seems to start the inflammatory process that is common in those with damaged tissue or who are warding off viruses or bacterial infection. While inflammation repairs and heals, chronic inflammation can damage healthy cells, tissues and organs, eventually leading to heart problems, arthritis, diabetes and some cancers.
In particular, social isolation seemed to release C-reactive protein, an inflammatory marker, into the bloodstream, the researchers noted after studying 30 studies.
While the association is clearly there, the researchers weren't sure if it was social isolation on its own that caused the inflammatory response, or whether it was a response to stress in the lonely person.
The researchers also cautioned to not lump social isolation and loneliness together. They are not necessarily the same, and each seems to be linked to a different inflammatory response.
So during this time, it's even more important to reach out to loved ones by phone, or video call, to check they're okay.