Feeling isolated, left out, and without a sense of belonging or connection to anyone around you — in other words, grappling with loneliness — can be a grim experience.

Science suggests these pangs for companionship aren’t just uncomfortable. Chronic loneliness can have significant effects on our physical and mental health.

“What’s so powerful about loneliness is it affects everything — every aspect of health and well-being,” says Angelina Sutin, PhD, a professor of psychology at Florida State University College of Medicine in Tallahassee, who researches how personality and life events affect mental and physical outcomes. “This underscores the importance of social connection and being able to be part of a group.”

Loneliness is the emotional and cognitive discomfort or uneasiness of being or perceiving oneself to be alone — the distress we feel when our inherent needs for intimacy and connection aren’t met.

It can bubble up as either an objective or subjective state. You could be objectively alone and crave companionship, or you could be in a crowded room and still feel alone in the world, says Julianne Holt-Lunstad, PhD, professor of psychology and neuroscience at Brigham Young University in Provo, Utah. For the past two decades, she’s been studying the protective effects of social relationships on health — and, in turn, the health risks associated with loneliness and isolation.

Limiting social interaction for months and years, for some, because of a global pandemic has been a stark reminder of the toll loneliness can take. In February 2021, Harvard University research reported that 36 percent of Americans said they felt “serious loneliness.”

Another international study (for which Dr. Holt-Lunstad was a coauthor) included 101 countries and suggested approximately 21 percent of people experienced “severe” loneliness in 2020 (only 6 percent reported that level of loneliness before COVID-19).

The increasing number of people experiencing loneliness led to the release of a U.S. Surgeon General’s Advisory in 2023, calling attention to loneliness as an urgent public health issue.

While nearly everyone experiences loneliness at some point, it’s chronic loneliness that wreaks havoc on our health. Here’s a look at seven ways loneliness affects our health and well-being.

1. Loneliness May Lead to Poor Health Habits

Evidence suggests people who feel lonelier may engage in more unhealthy behaviors compared with people who feel more socially connected.

Research suggests single or widowed seniors eat fewer vegetables and fruits than their peers who are married or cohabitating.

Other research found that people who are lonely were significantly less likely to exercise than people who felt less lonely.

Factors like marital status, contact with close social ties, and social network size did not explain why people were more or less likely to exercise, but reported feelings of loneliness did.

One report found that loneliness led people to poor health behaviors. Forty-three percent of people who felt loneliness turned to binge eating, 34 percent smoked cigarettes, and 21 percent abused alcohol or drugs to soothe their feelings.

These lifestyle factors play a key role in people’s health trajectories, Holt-Lunstad says. Her ongoing research on the COVID-19 pandemic is attempting to better understand how loneliness stemming from lockdowns and social distancing worsened our health overall.

“When people are isolated and lonely, they tend to eat more, they don’t work out, they get worse sleep. Their health-related behaviors become worse,” she says.

3. Loneliness May Increase Risk of Depression

Loneliness is a major risk factor for developing depression, with many symptoms overlapping (like experiencing feelings of emotional pain and helplessness).

In a study published in January 2021 in The Lancet Psychiatry, researchers concluded that loneliness increases the risk of depression.

The researchers had a group of more than 4,200 adults in England answer questions about their experiences of loneliness, social support, and symptoms of depression.

Each 1-point increase on the 20-point loneliness scale used was linked to a 0.16-point increase in depressive symptoms. Depression also increased over time among participants with greater loneliness scores, hinting that present day loneliness may be a marker for future depression.

4. Loneliness May Trigger Chronic Inflammation

Inflammation is part of how our immune systems kick into action to protect us against harm or disease, or heal.

Chronic inflammation is this process gone awry. The body continues to send distress signals even though there’s no injury or danger. This type of chronic inflammation causes chronic health problems, like heart disease, type 2 diabetes, rheumatoid arthritis, and cancer.

In a meta-analysis, researchers concluded that people who are more socially isolated have higher levels of inflammatory chemicals that are associated with poor health.

That finding suggests that our bodies interpret loneliness as stress, injury, or pain.

5. Chronic Loneliness Increases Dementia Risk

Adults who report greater feelings of loneliness are at a 40 percent increased risk of developing dementia and other cognitive impairments, according to a study led by Dr. Sutin that was published in 2018.

The research analyzed data from a U.S. longitudinal study of more than 12,000 people, making it the largest sample to date to look at loneliness and dementia. Study participants were 50 and older. They completed surveys to measure loneliness and completed cognitive tests every two years over the course of a decade.

Sutin says that people who were lonely had risk factors for diabetes, hypertension, depression, and other concerns, but even after adjusting for those shared risks, loneliness still predicted increased risk of dementia.

Making conversation and nurturing relationships with coworkers, loved ones, neighbors, and others is great for our cognitive health, Sutin says. “There’s something about connecting with other people, having a reason to get up in the morning to engage with the world that protects the brain. It’s about keeping the brain active and on its toes,” she says.

Other research aligns, suggesting that feeling lonely, not social isolation, is what increases dementia risk.

And another study among Chinese adults suggests that the risk is higher for men.

7. Loneliness May Shorten Your Life

Ultimately, loneliness takes a grave toll on our health, with research suggesting that both living alone and feeling subjective loneliness increases risk of premature death by 32 and 26 percent. These findings stem from a meta-analysis that involved over 3.4 million participants, which was led by Holt-Lunstad.

Potential confounding factors were controlled for.

“When we’re alone or away from a group we, in essence, have to deal with everything by ourselves and our brains are much more vigilant. It’s like being in a constant heightened state of alert similar to a fight or flight mode,” Holt-Lunstad says.

On the flipside, Holt-Lunstad’s research found that strong social connection is linked to a 50 percent reduced risk of an early death.

In this case, researchers followed the health trajectories of more than 308,000 people over the course of seven and a half years. They found that scoring low on indicators of social connection was a greater risk to health than air pollution, obesity, smoking, and excessive drinking.

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Sources

Loneliness. American Psychological Association. April 19, 2018.
Weissbourd R et al. Loneliness in America: How the Pandemic Has Deepened an Epidemic of Loneliness and What We Can Do About It. Harvard Graduate School of Education. February 2021.
O’Sullivan R et al. Impact of the COVID-19 Pandemic on Loneliness and Social Isolation: A Multi-Country Study. International Journal of Environmental Research and Public Health. September 2021.
Our Epidemic of Loneliness and Isolation: The U.S. Surgeon General’s Advisory on the Healing Effects of Social Connection and Community. U.S. Department of Health and Human Services. 2023.
Evidence Brief 5: Multiple Social Ties and Healthy Eating in Older People. Communicating Diet and Activity Research. October 2013.
Hawkley LC et al. Loneliness Predicts Reduced Physical Activity: Cross-Sectional and Longitudinal Analyses. Health Psychology. 2009.
DiJulio B et al. Loneliness and Social Isolation in the United States, the United Kingdom, and Japan: An International Survey. Kaiser Family Foundation. August 30, 2018.
McLay L et al. Loneliness and Social Isolation Is Associated With Sleep Problems Among Older Community Dwelling Women and Men With Complex Needs. Scientific Reports. March 1, 2021.
Kurina LM et al. Loneliness Is Associated With Sleep Fragmentation in a Communal Society. Sleep. November 1, 2011.
Mushtaq R et al. Relationship Between Loneliness, Psychiatric Disorders and Physical Health? A Review on the Psychological Aspects of Loneliness. Journal of Clinical and Diagnostic Research. September 2014.
Lee SL et al. The Association Between Loneliness and Depressive Symptoms Among Adults Aged 50 Years and Older: A 12-Year Population-Based Cohort Study. The Lancet Psychiatry. January 2021.
What Is Inflammation? Harvard Health Publishing. April 12, 2021.
Inflammation. Cleveland Clinic. December 20, 2023.
Smith K et al. The Association Between Loneliness, Social Isolation and Inflammation: A Systematic Review and Meta-Analysis. Neuroscience and Biobehavioral Reviews. May 2020.
Sutin A et al. Loneliness and Risk of Dementia. The Journals of Gerontology: Series B. September 2020.
Holwerda TJ et al. Feelings of Loneliness, but Not Social Isolation, Predict Dementia Onset: Results From the Amsterdam Study of the Elderly (AMSTEL). Journal of Neurology, Neurosurgery, and Psychiatry. February 2014.
Zhou Z et al. Loneliness and the Risk of Dementia Among Older Chinese Adults: Gender Differences. Aging and Mental Health. April 2018.
Valtorta NK et al. Loneliness and Social Isolation as Risk Factors for Coronary Heart Disease and Stroke: A Systematic Review and Meta-Analysis of Longitudinal Observational Studies. Heart. July 2016.
Udell JA et al. Living Alone and Cardiovascular Risk in Outpatients at Risk of or With Atherothrombosis. JAMA Internal Medicine. July 23, 2012.
Hawkley LC et al. Loneliness Predicts Increased Blood Pressure: 5-Year Cross-Lagged Analyses in Middle-Aged and Older Adults. Psychology and Aging. March 2010.
Holt-Lunstad J et al. Loneliness and Social Isolation as Risk Factors for Mortality: A Meta-Analytic Review. Perspectives on Psychological Science. March 2015.
Holt-Lunstad J et al. Social Relationships and Mortality Risk: A Meta-Analytic Review. PLoS Medicine. July 27, 2010.

Show Less

Meet Our Experts

See Our Editorial PolicyMeet Our Health Expert Network

Allison Young, MD

Medical Reviewer

Allison Young, MD, is a board-certified psychiatrist providing services via telehealth throughout New York and Florida.

In addition to her private practice, Dr. Young serves as an affiliate professor of psychiatry at Florida Atlantic University Charles E. Schmidt College of Medicine. She previously taught and mentored medical trainees at the NYU Grossman School of Medicine. She speaks at national conferences and has published scientific articles on a variety of mental health topics, most notably on the use of evidence-based lifestyle interventions in mental health care.

Young graduated magna cum laude from Georgetown University with a bachelor of science degree in neurobiology and theology. She obtained her doctor of medicine degree with honors in neuroscience and physiology from the NYU Grossman School of Medicine. She continued her training at NYU during her psychiatry residency, when she was among a small group selected to be part of the residency researcher program and studied novel ways to assess and treat mental distress, with a focus on anxiety, trauma, and grief.

During her psychiatry training, Young sought additional training in women’s mental health and cognitive behavioral therapy. She has also studied and completed further training in evidence-based lifestyle interventions in mental health care, including stress management, exercise, and nutrition. She is an active member of the American College of Lifestyle Medicine, through which she helps create resources as well as educate physicians and patients on the intersection of lifestyle medicine and mental health.

See full bio

Carmen Chai

Author

Carmen Chai is a Canadian journalist and award-winning health reporter. Her interests include emerging medical research, exercise, nutrition, mental health, and maternal and pediatric health. She has covered global healthcare issues, including outbreaks of the Ebola and Zika viruses, anti-vaccination movements, and chronic diseases like obesity and Alzheimer’s.

Chai was a national health reporter at Global News in Toronto for 5 years, where she won multiple awards, including the Canadian Medical Association award for health reporting. Her work has also appeared in the Toronto Star, Vancouver Province, and the National Post. She received a bachelor’s degree in journalism from Ryerson University in Toronto.

See full bio

What Does the Science Say About How Loneliness Affects Our Health?