People who are lonely are more likely to have sleepless nights, new research suggests.
The study means loneliness may not only cause unhappiness, it may also be bad for your health.
Lianne Kurina of the University of Chicago studied loneliness and sleep patterns among a group of older residents living in two colonies in South Dakota.
People in this religious sect live communally, sharing possessions and meals. They are rarely socially isolated.
She said the findings were similar to those from a 2002 study of college students that compared feelings of loneliness to sleep quality. It found that the lonelier the students felt, the more fitfully they slept.
The researchers collected information on feelings of loneliness, blood pressure and sleep from 95 residents of the Hutterite communities.
To measure sleep, study volunteers wore wrist bands that measured their activity and level of restlessness during sleep.
Among the residents, roughly half said they were not lonely. But among the remaining half, the researchers noted a trend between increasing feelings of loneliness and social isolation and more fitful sleep.
"Basically, the lonelier individuals had sleep that was more broken up.
"There was more movement during the night, more periods of short sleep duration, more tossing and turning," Ms Kurina.