Researchers have discovered that loneliness actually triggers physical responses in the body which make people sick.
The study by the University of Chicago and the University of California found that
lonely people had a less effective immune response and more inflammation than non-lonely people. They feel socially threatened which has an enormous impact on health.
‘Lonely people had a less effective immune response and more inflammation than non-lonely people. They feel socially threatened which has a huge impact on health.
John Capitanio, of the California National Primate Research Centre at the University of California, Davis said: "Perceived social isolation is a risk factor for chronic illness and all-cause mortality but the molecular mechanisms remain ill understood. In humans, loneliness involves an implicit hyper-vigilance for social threat."
The research examined loneliness in both humans and rhesus macaques (one of the best-known species of Old World monkeys), a highly social primate species. Previous research has found that norepinephrine (a hormone which is released by the adrenal medulla and by the sympathetic nerves and functions as a neurotransmitter) can stimulate blood stem cells in bone marrow to make more of a particular kind of immune cell which ramps up inflammation in the body.
Both lonely humans and monkeys showed higher levels of monocytes in their blood. Also, monkeys repeatedly exposed to mildly stressful social conditions such as unfamiliar cage-mates also showed increases in monocyte levels.
The researchers also showed that, in monkeys at least, the lonliness changes allowed simian immunodeficiency virus to grow faster in both blood and brain. Finally, the researchers determined that this monocyte-related CTRA shift had real consequences for health.
The study was published in the Proceedings of the National Academy of Sciences.