SLEEP-DEPRIVED PEOPLE feel lonelier and less inclined to engage with others, avoiding close contact in much the same way as people with social anxiety, a new study has found.

That alienating vibe also makes sleep-deprived individuals more socially unattractive to others. Moreover, well-rested people feel lonely after just a brief encounter with a sleep-deprived person, potentially triggering a viral contagion of social isolation.

The findings, which have been published in the Nature Communications journal, are the first to show a two-way relationship between sleep loss and becoming socially isolated, shedding new light on a global loneliness epidemic.

“We humans are a social species. Yet, sleep deprivation can turn us into social lepers,” said senior study author Matthew Walker of University of California, Berkeley said.

The researchers found that brain scans of sleep-deprived people as they viewed video clips of strangers walking towards them showed a powerful social repulsion in neural networks that are typically activated when humans feel their personal space being invaded.

Sleep loss also blunted activity in brain regions that normally encourage social engagement.

“The less sleep you get, the less you want to socially interact. In turn, other people perceive you as more socially repulsive, further increasing the grave social-isolation impact of sleep loss,” Walker said.

“That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”

Study method

To gauge the social effects of poor sleep, Walker and co-author Ben Simon conducted a series of intricate experiments using brain imaging, videotaped simulations, standardised loneliness measures and surveys.

First, the researchers tested the social and neural responses of 18 healthy young adults following a normal night’s sleep and a sleepless night.

The participants watched video clips of individuals with neutral expressions walking towards them. When the person in the video got too close, they pushed a button to stop the video. This recorded how close they allowed the person to get.

As predicted, sleep-deprived participants kept the approaching person at a significantly greater distance away (between 18 and 60% further back) than when they had been well-rested.

The participants also had their brains scanned as they watched the videos of individuals approaching them. In the sleep-deprived brains, researchers found heightened activity in a neural circuit known as the “near space network”, which is activated when the brain perceives potential incoming threats from humans.

For the online section of the study, over 1,000 observers viewed videotapes of study participants discussing commonplace opinions and activities.

They were unaware that the subjects had been deprived of sleep and rated each of them based on how lonely they appeared, and whether they would want to socially interact with them.

Time and time again, they rated study participants in the sleep-deprived state as lonelier and less socially desirable.

Researchers also found that otherwise healthy observers felt alienated after viewing just a 60-second clip of a lonely person.

One night of bad sleep

Finally, researchers looked at whether just one night of good or bad sleep could influence a person’s sense of loneliness the next day.

Each person’s state of loneliness was tracked via a standardised survey that asked questions such as, “How often do you feel isolated from others” and “Do you feel you don’t have anyone to talk to?”.

Notably, researchers found that the amount of sleep a person got from one night to the next accurately predicted how lonely and unsociable they would feel from one day to the next.

“This all bodes well if you sleep the necessary seven to nine hours a night, but not so well if you continue to short-change your sleep,” Walker said.

“On a positive note, just one night of good sleep makes you feel more outgoing and socially confident, and furthermore, will attract others to you.”