When we worry about our health, we worry about the obvious things: a family history of cancer, following a poor diet, engaging in substance abuse.
We rarely think about how our sleep affects our health, or how our interpersonal relationships do. New research out of UC Berkeley suggests both of these are more essential to our overall well-being than we may realize.
Studying the link between sleep and loneliness
The study, titled “Sleep loss causes social withdrawal and loneliness,” was published last week in the journal Nature Communications. Researchers tested the effects of sleep deprivation on social isolation, using a combination of in-lab testing and video observations through Amazon’s Mechanical Turk.
In one part of the study, participants were invited to watch video clips of strangers with neutral expressions walking toward them. Participants were told to push a button to stop the video when the person got too close. Participants performed the exercise after a night of full sleep and after a night of sleep deprivation.
When they were sleep-deprived, participants stopped the video between 18% to 60% earlier than when they were well-rested. In other words, participants prevented the stranger from getting as close as they allowed them to when they were well-rested – suggesting that sleep-deprived individuals are more likely to refrain from social interaction.
During the exercise, the researchers observed the participants’ brain scans. They noted interesting activity in two parts of the brain. When the participants were sleep deprived, activity in the area of the brain responsible for social interaction ceased. Meanwhile, the area of the brain responsible for perceiving incoming threats lit up – indicating that sleep-deprived individuals may be more likely to view neutral social interaction as threatening.
When researchers asked participants how lonely they felt, they were most likely to feel lonely and antisocial in the days following sleep-deprivation than when they were well-rested.
In another part of the study, the researchers filmed the sleep-deprived study participants conversing about everyday topics. They recruited 1,000 participants via Amazon Mechanical Turk to watch the footage, and answer questions about how they would rate each participant’s levels of loneliness and “social desirability” – essentially, whether they would want to interact with the person. When the participants were sleep-deprived, the observers rated them as significantly more lonely and less socially desirable.
Finally, researchers asked the observers to rate their own feelings of loneliness, after they had watched a 60-second clip of a lonely participant. The more lonely the observer had rated the participant, the more lonely they would rate themselves, indicating that sensing loneliness in others is almost contagious.
What does this study tell us about our sleep and social health?
Matthew Walker, senior author of the study, summarized the study findings nicely: “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. That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”
He’s not exaggerating when he calls loneliness a “public health crisis.” Just under half (46%) of Americans feel lonely sometimes or always, according to a 2018 survey of 20,000 adults.
This isn’t just sad; it’s scary. Several meta-analyses have found that feelings of loneliness or social isolation can increase your mortality risk by over 30%. That’s equivalent to smoking 15 cigarettes a day.
At the same time, sleep deprivation is sweeping the country to such an extent that the CDC has labeled it a public health epidemic. More than a third of Americans don’t get enough sleep on a regular basis (defined as 7 hours or more of sleep per night). Like social isolation, sleep deprivation is also independently linked to a variety of health conditions that increase one’s mortality risk, including diabetes, stress, heart disease, obesity, depression and anxiety.
Given the independent links between social isolation and poor health, as well as sleep deprivation and poor health, these findings reveal how poor sleep and feelings of social isolation contribute to and compound each other. When we’re sleep deprived, we feel lonelier, we keep people at a distance, and we’re less willing to interact socially. In turn, those actions make us feel more lonely, and as a social species, that loneliness is contagious, even among non-sleep deprived individuals.
“We humans are a social species. Yet sleep deprivation can turn us into social lepers,” said Walker. It’s a bold statement, but his research supports it.
Fortunately, there’s good news: good sleep reduces feelings of loneliness and social isolation. To sleep better and improve your social life, get good sleep and often.