Do I sleep worse if I am often alone or feel lonely?

Lonely people are 75% more likely to experience poor sleep than people who do not feel lonely. This emerges from a meta-analysis of 16 studies involving more than 23,000 older participants. A second, much larger analysis of 114 studies confirms this: loneliness has a medium to large negative effect on sleep.

More concretely: if you feel lonely, you lie awake on average about 9 minutes longer before falling asleep (35 minutes versus 27 minutes for people who do not feel lonely). You also wake up more often during the night and feel sleepier and more tired during the day. Yet loneliness makes no difference to the time you go to bed or wake up -- the rhythm itself remains intact.

Part of the relationship runs through your mood. In people with type 2 diabetes, loneliness had no directly measurable effect on sleep, but it did have an indirect one: loneliness fuels depressive symptoms, which in turn worsen sleep. That pattern also makes biological sense: when you are lonely, your nervous system and stress hormones respond as they would to impending danger -- a kind of unconscious hypervigilance. This literally keeps your brain on alert and makes restful sleep harder to achieve.

Whether you feel lonely is therefore more relevant than whether you are objectively alone. Improving social contact or addressing feelings of loneliness -- through conversation, therapy or more meaningful connections -- is thus also a concrete avenue toward better sleep.