As if feeling lonely during the waking hours wasn't bad enough, a new study from the University of Chicago says feelings of isolation may negatively affect a person's quality of sleep.
Researchers found that people who reported feeling isolated from others tossed and turned more throughout the night than those who said they felt socially connected.
The lonely sleepers got about the same amount of sleep, and didn't report feeling more tired the next day. But sensors that researchers attached to the subjects' wrists found that they stirred more than participants who professed to be more gregarious.
The findings may help explain why loneliness has been linked to poor health. For example, in studies published in his 2008 book Loneliness: Human Nature and the Need for Social Connection, John Cacioppo, a professor of psychology at the University of Chicago, found that chronic loneliness can lead to higher blood pressure, reduced immune system functions and increased depression.
The new research is published in the current edition of the journal Sleep.
"Loneliness was a significant predictor of sleep fragmentation," the authors write. "Humans' social nature may partly be manifest through our dependence on feeling secure in our social environment to sleep well."
The 100 participants, who ranged in age from 19 to 84, all have similar backgrounds: They belong to a tight-knit Hutterite community in South Dakota, have nearly identical diets and are non-smokers. Most went to bed between 9:30 p.m. and 11:30 p.m. and woke between 5 a.m. and 7 a.m.
The participants were asked how often they felt lonely. Researchers then rated them on a loneliness scale. Increases on the scale were linked to increases in broken sleep.
"The [Dakotan]group was not very lonely as a whole," Lianne Kurina, the paper's lead author and assistant professor of epidemiology at the University of Chicago, told Time. "But what I found most surprising was that even subtle differences in the feelings of loneliness showed up in the sleep."
Do you notice a difference in how you feel after a night of bad sleep? How do you make up for the lack of ZZZZs?