Can Sleep Deprivation Make You Lonely? What This Study Found

By Grant Frost · Physiotherapist • Last clinically reviewed: 09 October 2026

We often think about sleep in fairly simple terms. Sleep helps us feel rested, gives us more energy and helps us get through the following day without walking around like a human zombie.

But sleep may influence far more than how tired we feel. A fascinating 2018 study from researchers at the University of California, Berkeley, investigated whether losing sleep could also change the way we interact with other people.

The results were surprisingly consistent. After sleep loss, people tended to keep more distance from others, reported greater feelings of loneliness, and were perceived by other people as being lonelier and less desirable to interact with.

So could poor sleep actually make us more socially isolated?

The answer from this study is: it may play a role. But the details are where this research becomes particularly interesting.

Why Sleep Matters More Than Just Feeling Rested

Sleep is not simply downtime. It's an important biological process involved in regulating mood, cognition, physical recovery and many other aspects of health.

From a physiotherapy perspective, sleep is particularly relevant because pain, sleep and recovery can influence one another. What makes the Berkeley study particularly interesting is that it looked beyond physical recovery and asked a different question:

Could losing sleep actually change the way we interact with other people?

What Did the Study Actually Do?

This is important because the study was more sophisticated than simply asking a group of tired people whether they felt lonely.

The researchers used three complementary parts.

1. An experimental sleep-deprivation study: 18 healthy young adults completed two sessions. One followed a normal night's sleep and the other followed 24 hours of total sleep deprivation.
2. A more natural sleep study: 138 people completed sleep and loneliness assessments across two consecutive nights. This allowed researchers to examine whether ordinary night-to-night changes in sleep efficiency were associated with changes in loneliness the following day.
3. An independent observer study: 1,033 people watched short videos of the participants and rated characteristics including loneliness and their desire to interact or collaborate with them.

That combination is one of the strengths of the paper. The researchers were able to look at both an experimentally induced night of total sleep deprivation and more modest variations in sleep quality that occur in everyday life.

Importantly, the study focused heavily on sleep quality and sleep efficiency, not simply the number of hours someone spent in bed.

Does Sleep Deprivation Make You More Socially Withdrawn?

In the experimental part of the study, the answer appeared to be yes.

After one night of total sleep deprivation, participants chose greater social distance from other people. In other words, they preferred to keep more physical space between themselves and another person.

The difference was observed using both an in-person social-distance task and a computer-based version while participants underwent functional MRI scanning.

The researchers reported approximately a 13% increase in social distance during the in-person task and an approximately 18% increase during the computerised task following sleep deprivation.

Interestingly, these changes were not simply explained by changes in mood or anxiety. The researchers found that the relationship between sleep loss and social withdrawal remained after accounting for these factors.

The fMRI component also suggested changes in brain networks involved in responding to approaching people and interpreting other people's intentions. That gives the findings a potential neurological explanation, although it is important not to overinterpret brain-imaging results as a simple cause-and-effect explanation for complex social behaviour.

Can Loneliness Be Socially Contagious?

This is probably the most attention-grabbing part of the study.

The researchers showed short videos of the participants to more than 1,000 independent judges. The judges did not know whether the person in the video had a normal night's sleep or were sleep deprived.

Interestingly, they rated the sleep-deprived participants as being significantly lonelier and less desirable to interact with.

Even more interestingly, the judges themselves reported feeling lonelier after watching the videos of sleep-deprived participants.

The researchers described this as a potential form of "infectious loneliness".

The study suggests that the social behaviour and presentation associated with sleep loss may influence the emotional state and social behaviour of the people around us.

Can We Generalise These Findings?

As a Physiotherapist, I value evidence-based practice, but I also think it is important to understand exactly what a study can and cannot tell us.

The first part of this research involved only 18 healthy adults aged between 18 and 24. They were deliberately selected as healthy participants and underwent an extreme intervention: 24 hours without sleep.

Most people do not regularly stay awake for 24 hours. So it's a little harder to assume that one ordinary late night will suddenly make you socially isolated.

However, the researchers also included a second study involving more modest, real-world variations in sleep quality.

Among the 138 participants who completed both days of that study, a reduction in sleep efficiency from one night to the next was associated with greater loneliness the following day. The relationship was relatively modest, but it moved in the same direction as the experimental findings.

That makes the findings more interesting. We are not only talking about an extreme all-nighter. The researchers also found an association between ordinary changes in sleep quality and next-day changes in loneliness.

At the same time, this was a short-duration study with relatively specific participant groups and online samples. It does not tell us whether chronic sleep problems cause long-term social isolation, nor does it establish that improving sleep will automatically resolve loneliness.

So I think the sensible takeaway is not "sleep deprivation makes you lonely."

It is this:

Sleep appears to be one factor that can influence how socially connected we feel and how we interact with the people around us.

What Does This Mean From a Physiotherapy Perspective?

This study wasn't a physiotherapy study, and it didn't investigate pain, injury or rehabilitation.

But I think it still has relevance to physiotherapy because sleep is one of those factors that can sit quietly in the background of a person's recovery.

When someone is dealing with persistent pain, fatigue or an injury that doesn't seem to be settling as expected, it's tempting to focus entirely on the painful body part.

But the body doesn't operate in isolated compartments.

Sleep, stress, physical activity, pain, mood and social connection can all interact. Clinically, I see poor sleep associated with increased pain sensitivity and intensity, and is always something worth exploring when looking for ways to help improve a person's pain experience.

Sometimes improving recovery is not about finding one magical exercise or treatment. It's about identifying the collection of factors that are making recovery harder than it needs to be.

How Can You Protect Your Sleep?

This particular study did not test sleep treatments or sleep-hygiene strategies, however, protecting sleep is still a sensible health priority.

Some practical areas worth exploring include:

• Keep your sleep schedule reasonably consistent: Regular sleep and wake times can help support a stable sleep routine.
• Give yourself enough opportunity to sleep: It is difficult to consistently get enough sleep if the schedule simply doesn't allow enough time in bed.
• Pay attention to your sleep environment: A dark, quiet and comfortable bedroom can make it easier to sleep.
• Be mindful of caffeine and alcohol: Both can interfere with sleep in some people, particularly when timing or quantity becomes an issue.
• Move regularly during the day: Regular physical activity is associated with better sleep and is also important for general physical health.
• Take persistent sleep problems seriously: If sleep is consistently poor despite giving yourself enough opportunity to sleep, it may be worth discussing the problem with your GP or another appropriate health professional.

Related: Are you aware of the impact of blue light on our sleep?

Conclusion: Sleep May Be More Social Than We Think

This study gives us another reason to take sleep seriously.

The researchers found that sleep loss was associated with greater social withdrawal and loneliness. They also found that people observing sleep-deprived individuals perceived them as lonelier and less desirable to interact with, while reporting greater feelings of loneliness themselves.

That's a pretty remarkable finding.

But I think the most useful message is also the simplest one: sleep is not just about feeling less tired.

It may influence how we think, how we feel, how we recover and, potentially, how we connect with other people.

So if sleep has gradually slipped down your priority list, perhaps it is worth moving it back up.

Not because one bad night will suddenly make you lonely, but because consistently good sleep is one of the foundations that helps support the rest of your health.

 

Want personalised guidance?

If you'd like help with an ache, pain or injury that just isn't going away you can book with Grant either in Port Macquarie or via an online telehealth consultation.

Book In-Person (Port Macquarie) Book Online Telehealth Consultation