Loneliness poses a serious physical risk—it can be, quite literally, deadly. As a predictor of premature death, insufficient social connection is a bigger risk factor than obesity and the equivalent of smoking up to 15 cigarettes a day, according to Julianne Holt-Lunstad, a psychology professor at Brigham Young University and one of the leading figures in loneliness research. And, she says, the epidemic is only getting worse.

But before we can fight back, we need to know exactly what we’re up against—and start taking it seriously.

What It Is, What It’s Not

It’s been well established that lonely people are more likely than the nonlonely to die from cardiovascular disease, cancer, respiratory illness, and gastrointestinal causes—essentially, everything. One study found that those with fewer than three people they could confide in and count on for social support were more than twice as likely to die from heart disease than those with more confidants. They were also roughly twice as likely to die of all causes, even when age, income, and smoking status were comparable.

Apart from the risk of premature death, loneliness contributes to seemingly countless health woes. Consider the common cold: A study published last year, in which lonely and nonlonely people were given cold-inducing nasal drops and quarantined in hotel rooms for five days, found that the lonely people who got sick suffered more severe symptoms than the nonlonely. “Put simply, lonelier people feel worse when they are sick than do less lonely people,” writes study author Angie LeRoy, a doctoral candidate at the University of Houston.

But what does it mean to be lonely, exactly? One of the most surprising revelations is the extent to which loneliness afflicts those of us who aren’t isolated in any traditional sense of the term, including people who are married or who have relatively large networks of friends and family.

“Loneliness is not simply being alone,” says John Cacioppo, the director of the University of Chicago’s Center for Cognitive and Social Neuroscience and the author of Loneliness: Human Nature and the Need for Social Connection. He points out that many of us crave solitude, which feels restorative and peaceful when desired. What might qualify as pleasant for some, however, can be misery for others—or even for the same person at different times.

Unlike most previous research, which has focused on the number of people in a patient’s social network, LeRoy’s cold study looked at both objective social isolation and subjective loneliness: the discrepancy between the patient’s actual and desired social relationships. Loneliness is a perceptual state that depends more on the quality of a person’s relationships than on their sheer number. People with few friends can feel fulfilled; people with vast social networks can feel empty and disconnected. What LeRoy and her colleagues found was that subjective loneliness was a far bigger risk factor than sheer social isolation. “It’s all about how the person feels,” she says. “Feelings really matter.”

And how exactly does the feeling of chronic loneliness hurt us? In addition to making us more susceptible to viruses, it’s also strongly correlated with cognitive decline and dementia. Lonely people are more than twice as likely to develop Alzheimer’s as the nonlonely. And researchers make a point of distinguishing the effects of loneliness from those of depression: Depression does elevate the risk for Alzheimer’s slightly, but not nearly as much as loneliness.

It’s easy to see how loneliness and depression would go hand in hand; the two states seem to feed off each other. Cacioppo defines loneliness as “a debilitating psychological condition characterized by a deep sense of emptiness, worthlessness, lack of control, and personal threat.” Some of those characteristics apply equally to depression, and it’s true that loneliness sometimes gives way to depression.

But recent studies show that while loneliness can be an accurate predictor of depression, depression doesn’t necessarily predict loneliness. (And, of course, loneliness is far from the only trigger for depression.) The key difference between the two, Cacioppo argues, is that loneliness not only leads to an increase in depressive symptoms but also to increased stress, anxiety, and even anger. Loneliness makes us sad, certainly, but the sense of personal threat seems to be what makes it so physically toxic. “These data suggest that a perceived sense of social connectedness serves as a scaffold for the self,” Cacioppo writes. “Damage the scaffold, and the rest of the self begins to crumble.”

Primal Roots

Our drive for social connectedness is so deeply wired that being rejected or socially excluded hurts like an actual wound. UCLA psychologist Naomi Eisenberger demonstrated the overlap between social and physical pain with an experiment in which subjects played an online game, tossing a virtual ball back and forth, while their brain activity was measured. Only one player was human; the others were created by a computer program. At some point, the computer “players” stopped tossing the ball to their human teammate. What Eisenberger found was that the brain activity of the rejected player strongly resembled that of someone experiencing physical pain.

Likewise, Eisenberger has found that the same painkillers we take for physical suffering can ease the ache of loneliness. In animal tests, morphine lessened the distress of social separation as well as it relieved physical pain. In human studies, experimenters used Tylenol instead of morphine—and it helped, too. Activity in the brain’s pain-processing regions was significantly reduced in subjects who took acetaminophen before being excluded from the ball-tossing game.

It’s no accident that loneliness hurts. Like the pain receptors that evolution planted in our bodies so we would keep our distance from a fire, the pain of loneliness grabs our attention and urges us to seek a remedy. Humans are social animals, after all, and collaboration has insured our survival against other animals. In our early days, the pain of loneliness would have been a powerful reminder to rejoin the pack when we strayed or risk fiercer pain if we encountered a predator all alone. “Loneliness evolved like any other form of pain,” Cacioppo says. “It is an aversive state that has evolved as a signal to change behavior, very much like hunger, thirst, or physical pain, to motivate us to renew the connections we need to survive and prosper.”

Feeling disconnected from the people we rely on for help and support puts us on high alert, triggering the body’s stress response. Studies show that lonely people, like most people under stress, have less restful sleep, higher blood pressure, and increased levels of the hormones cortisol and epinephrine; these, in turn, contribute to inflammation and weakened immunity.

While the pain of loneliness was an adaptive advantage in humanity’s early days, when separating from the tribe could mean becoming lion food, it doesn’t serve the same purpose now that we can technically survive entirely on our own, given a microwave and an endless supply of Hot Pockets. The force of the feeling may seem like overkill now that it has evolved from a life-or-death alarm bell into a more abstract warning that our need for connection is not being met. But that’s only until you consider that the need, left unmet, still has the power to kill us—just by a slower, more invisible mechanism than starvation or predation.

Counterintuitively, the pain of isolation can make us more likely to lash out at the people we feel alienated from. Once our fight-or-flight system is activated, we’re more likely to fight others than to hug them. Loneliness, Cacioppo explains, “promotes an emphasis on short-term self-preservation, including an increase in implicit vigilance for social threats.”

The emerging theory of loneliness, in other words, is that it doesn’t just make people yearn to engage with the world around them. It makes them hypervigilant to the possibility that others mean to do them harm—which makes it even less likely that they’ll be able to connect meaningfully.

This negative feedback loop is what makes chronic loneliness (as opposed to situational loneliness, which comes and goes in everyone’s life) so frustratingly intractable. In people who’ve been lonely for a long time, the fight-or-flight response has kicked into perpetual overdrive, making them defensive and wary in social settings. Chronically lonely people tend to approach a social interaction with the expectation that it will be unfulfilling and to look for evidence that they’re right. As Cacioppo notes, lonely people pay more attention to negative signals from others, interpreting judgment and rejection where  it  is  not  intended. Without being aware of it, they sabotage their own efforts to connect with others.

So injunctions to join a book club or social group won’t help unless people can first shed the unconscious biases that keep them from establishing intimacy. Experts like Cacioppo are approaching this problem from two angles: how to stop the feedback loop once it starts and, perhaps more promisingly, how to prevent it from starting at all. That means working to beef up social opportunities and deepen connections among those likely to become chronically lonely. But first they have to identify the people most at risk.

Who? Everyone

More Americans are living alone than ever before, making us more likely to become socially isolated, especially as we age. The number of older people without a spouse, child, or any living relatives is growing—and disproportionately so for older black Americans.

That’s one reason we’re lonelier. But it’s not the whole story. Being married doesn’t protect you from loneliness, according to a 2012 study, which followed 1,600 adults over 60 for six years. Out of the 43 percent of participants who reported chronic loneliness, more than half were married.

Everyone, of course, is lonely sometimes, especially after the loss of a loved one or a move to a new area. The very elderly are at a higher risk for chronic loneliness because they’ve often lost partners, siblings, and friends, and because health and mobility problems can get in the way of social activity. And that demographic is growing simply because life expectancy is increasing.

Loneliness has also skyrocketed among teens and young adults, despite their typically robust health and sizeable peer groups. A recent British study found that the youngest people surveyed—those between 16 and 24—were the most likely of all age groups to report feeling lonely. Many experts blame the growing loneliness of young people on their social media use, which they argue may hinder the development of the real-world social skills necessary to build close friendships.

In the United States, loneliness is especially lethal for military veterans. A 2017 study by Yale researchers found that the biggest contributor to veteran suicides—on average, 20 a day—was not war—related trauma but loneliness. Even soldiers who never saw combat are susceptible, Sebastian Junger reported in Tribe: On Homecoming and Belonging. Most devastating, for many of them, is the loss of what Junger terms “brotherhood”—the tight bonds formed through shared mission and sacrifice—and its stark contrast with our independent, isolated civilian society.

Overall, roughly 40 percent of Americans reported regularly feeling lonely in 2010, up from about 20 percent in the 1980s. According to a sociological report called the General Social Survey, the number of Americans who say they have no one they can confide in nearly tripled between 1985 and 2004: At the survey’s end, the average person reported having just two confidants.

Why? There are many reasons, but Sherry Turkle, the author of Alone Together: Why We Ask More From Technology and Less From Each Other, places blame squarely on the rise of digital culture. Connecting meaningfully with others in person requires us to be ourselves, openly and genuinely. Conversations by text or Facebook messenger may be filled with smile emojis, but they leave us feeling empty because they lack depth.

“Without the demands and rewards of intimacy and empathy, we end up feeling alone while together online,” Turkle says. “And when we get together, we are quite frankly less prepared than before to listen. We have lost empathy skills. And of course, this, too, makes us more alone.”

But even friends we interact with in the real world can put us at risk if they themselves become lonely. A stunning study by Cacioppo and fellow researchers Nicholas Christakis and James Fowler concluded that loneliness is contagious: It spreads in clusters throughout social networks. Their research, based on a 10-year study of more than 5,000 people, found that those who became lonely typically passed that feeling along to others before cutting ties with the group. As they describe it, ripples of loneliness along the margins of a social network, where people tend to have fewer friends to begin with, move inward toward the group’s center, infecting the friends of those lonely people, then friends of friends, leading to weakened ties among all.

“Our social fabric can fray at the edges, like a yarn that comes loose at the end of a crocheted sweater,” they write. “An important implication of this finding is that interventions to reduce loneliness in our society may benefit by aggressively targeting the people at the periphery to help repair their social networks. By helping them, we might create a protective barrier against loneliness that can keep the whole network from unraveling.”

How to Reconnect

Perched on a remote hillside in the rugged, rocky heart of Sardinia, Villagrande Strisaili doesn’t seem like a particularly hospitable place. The farmers and laborers who eke out a backbreaking living here greeted psychologist Susan Pinker with extreme wariness when she visited them. “Who are your parents?” one asked her.

But these villagers have something the rest of us covet: an average lifespan as much as three decades longer than their fellow Europeans (and us Americans). It’s one of the handful of mountainous regions in the world where more people live past the age of 100 than anywhere else. And what researchers, including Pinker, have found is that one key to their longevity may be that they live within a social fabric knit so tightly that, while seemingly impervious to outsiders, it shelters its residents in a uniquely warm, protective embrace.

Part of  the Sardinian stronghold’s secret is structural. As in all of Italy’s medieval villages, life literally and figuratively revolves around the town square, as it has for centuries. “You have to go through it to go to the post office or the church or the store,” says Pinker, the author of The Village Effect: How Face-to-Face Contact Can Make Us Healthier and Happier. “You have to meet your neighbors, whether you want to or not.”

Part, too, evolved from the region’s geographic isolation and the repeated invasions it has endured since the Bronze Age, which forced its early residents inland to hilltop enclaves that were easy to defend. Their descendants, Villagrande’s 3,500 modern-day dwellers, are bonded both by kinship and by millennia of shared history and common purpose.

So being born into a tight-knit community on a remote mountaintop where your ancestors fought off invaders for thousands of years, and where you’re forced to see your neighbors every day in the town square, is one way to prevent loneliness. But where does that leave the rest of us?

It’s possible to follow the Sardinian example by creating communities that deliberately foster close social bonds. There’s a growing cohousing movement in which residents share chores and tend to common spaces together, as they have in communes and kibbutzes. “It’s more popular in Sweden, Denmark, and Norway,” Pinker says. “There are about 700 cohousing communities in Denmark and 150 to 200 in the United States, but more are being built.”

Growing numbers of older Americans, meanwhile, are embracing what some are calling the “village movement,” forming neighborhood organizations where homeowners pay yearly dues to hire a small staff that helps with everything from minor home improvements to grocery shopping to organizing social activities. That way people can maintain the connections they’ve developed over a lifetime in their own neighborhoods and still receive the services they might otherwise get by moving into an assisted living facility.

Urban planners can help by designing communities that look more like Villagrande—if not with a town square at the center, then at least with parks and community centers where people are forced to cross paths. And we can all make a conscious choice to buy or rent homes in socially salubrious neighborhoods, Pinker says. “A lot of people look at a home’s closets and kitchen, but what they need to look at is where the people gather in the neighborhood. What’s the park like? Where’s the library? That’s much more important than how big your closet is.”

Even if we don’t live in a setting that puts us in regular contact with our neighbors, we can still cultivate connection by making it a priority akin to exercise, Pinker says. Combining workouts with social connection, in fact, does double duty: Pinker’s own research convinced her to change her solitary exercise habits, and she joined a swim team with whom she stretches both her physical and her social muscles.

We can find ways to engage with other people no matter what our interests are. “Just getting together to play cards once a week can add years onto your life—it’s better than taking beta blockers,” Pinker says. “But that’s not why you should do it. You should do it because it’s fun, because you enjoy it. Otherwise you won’t keep it up.”

What’s missing for lonely people, after all, is not just social contact but meaningful contact—the bonds that come from being your authentic self with another person. One of the best ways to foster meaningful engagement is through the creative arts, says health researcher Jeremy Nobel, who is spearheading an initiative called The UnLonely Project, which focuses on creative expression as a way to lessen the burden of loneliness.

Edythe Hughes, a 28-year-old model affiliated with The UnLonely Project, has made art a regular part of her social life. “Whenever I have people over, I always have  a  canvas and ask that everyone paint something,” she says. “Making art together pulls you into a deeper connection with each other.”

This is why traditional efforts to reach out to the lonely—by, say, visiting a nursing home—are often unsuccessful: They fail to foster deep, meaningful engagement. The encounter is pleasant but fleeting, and the effects don’t last. “If I talk to someone for an hour and then leave, they’re still lonely,” says Dutch sociologist Jenny Gierveld, who has spent 50 years studying loneliness. “The basis of a meaningful bond is reciprocity. A lonely person can’t just answer a lot of questions for an hour and feel connected. He or she has to do something.”

To foster the engagement that’s key to countering loneliness, Cacioppo and his colleagues at the University of Chicago designed what they call social fitness exercises and applied them to people at particularly high risk for chronic loneliness: soldiers returning from Iraq and Afghanistan. Working with 48 Army platoons, they taught the soldiers to identify behaviors that reinforce loneliness and to substitute more positive behaviors. For example, a soldier who kept looking down at his phone was reminded to put the phone away and engage with the people around him; someone tempted to avoid conversation was encouraged to ask a question instead. The training was shown to reduce loneliness among soldiers—and it might work equally well in civilian settings. “Just as you can start an exercise regimen to gain strength and improve your health, you can combat loneliness through exercises that build emotional strength and resilience,” Cacioppo writes.

A major barrier to treating loneliness, however, is the reluctance many feel to even acknowledge that it affects them. Unlike other health risks, such as hypertension or high cholesterol, it’s compounded by stigma. “It becomes about them as a person: They’re not worthy of friendship; they have less value in society,” Nobel says. But that may be changing with increasing awareness of how common and dangerous loneliness is.

“I’ve been working on this for my entire career, and within the last year there has been more attention paid to it than ever before, which gives me hope,” says psychologist and neuroscientist Holt-Lunstad. Last spring, she testified before the U.S. Senate Committee on Aging on the need to elevate loneliness to a public health priority on the same level as smoking and obesity.

“One of the biggest stumbling blocks in getting many organizations to take this seriously is the question, ‘What can we do about it?’ It feels, to many, more like a personal issue, something policymakers shouldn’t be getting involved in,” she says. But one of the issues that emerged during her testimony was that hearing loss among older Americans contributes to increased isolation and loneliness. Congress has since passed legislation to make hearing aids more accessible. “While it’s true that we can’t legislate good relationships, here’s legislation that can reduce loneliness, and it doesn’t impede on anyone’s personal freedom,” she says.

While an easy fix for loneliness is elusive, researchers are optimistic. It wasn’t so long ago, after all, that we connected meaningfully with each other more or less by default. We can figure it out again—especially now that we know what’s at stake. “More than just looking at new statistics about loneliness, it is time to trace the human story of  how we got here,” Turkle says. “It is not so complicated. We can retrace our way and rediscover one another’s company.”

Take the Fight to Loneliness

Once we understand the toll loneliness takes on our mental and physical health, what can we do to protect ourselves?

DO TALK TO STRANGERS

Small talk isn’t so small, so take the plunge and converse with someone beside you on the bus or in line at a store.”Just chatting makes us happier and healthier,” says Susan Pinker, author of The Village Effect. “We can feel much better after just 30 seconds of talking to someone in person, whereas we don’t get that benefit from online interaction.”

GIVE IT SEVEN MINUTES

According to the “seven-minute rule,” it takes that long to know if a conversation is going to be interesting. Sherry Turkle, the author of Alone Together and Reclaiming Conversation, acknowledges that it can be hard, “but it’s when we stumble, hesitate, and have those ‘lulls’ that we reveal ourselves most to each other.”

SCHEDULE FACE TIME

What does face-to-face contact with friends and family give us that virtual communication lacks? For one thing, it boosts our production of endorphins, the brain chemicals that ease pain and enhance well-being. That’s one reason in-person interaction improves our physical health, researchers say.

IF YOU CAN’T GET FACE TIME, CHOOSE FACETIME

Being there in person is always best, but video conferencing by Skype or FaceTime can help people divided by distance maintain the bonds they built in person, according to researchers. Phone calls are the next best thing—hearing the other person’s voice is a form of connection—while relationships conducted primarily by email or text tend to wither fastest.

USE FACEBOOK WISELY

Social media isn’t inherently alienating, says Harvard epidemiologist Jeremy Nobel, but to create sustainable connections, it should be used purposefully. “If you’re just using Facebook to show pictures of yourself smiling on vacation, you’re not going to connect authentically,” he says. Instead, within the larger platforms, create smaller social networks, such as an online book club where you can share meaningful personal reactions with a select group of people.

BE A GOOD NEIGHBOR

Getting to know your neighbors yields more benefits than access to a cup of sugar when you run out. One study found that higher “neighborhood social cohesion” lowers your risk for a heart attack. So invite your neighbors over for coffee and offer to feed their cats when they go out of town. You’ll be happier and healthier for it.

THROW A DINNER PARTY

“Eating together is a form of social glue,” writes Susan Pinker in The Village Effect. Evidence of communal eating dates back at least 12,000 years: Sharing food was a way to resolve conflicts and create a group identity among hunter-gatherers long before villages existed.

GET CREATIVE

Participating in the creative arts—from joining a chorus to organizing a craft night—helps us connect deeply without talking directly about ourselves, Nobel says. “A lot of people can’t find the spoken words to express their feelings, but they can draw them, write expressively about them, or even dance them,” he says. “When someone else pays attention to them and allows them to resonate with their own experience, it’s as if an electric circuit gets completed, and they’re connected.”

TALK ABOUT IT

When Julia Bainbridge struggled with loneliness as a single New Yorker, she started a podcast, The Lonely Hour, and found that just talking about her feelings made her feel less lonely. She was surprised to find out how many people felt the same way—and what a relief it was to know that she wasn’t alone in her loneliness. Whether to a podcast audience, a friend, or a therapist, we can all benefit from talking about feelings of isolation.

REACH OUT AND TOUCH SOMEONE—LITERALLY

Hugging, holding hands, or even just patting someone on the back is powerful medicine. Physical touch can lower our physiological stress response, helping fight infection and inflammation. And it cues our brains to release oxytocin, which helps strengthen social bonds.