Most Americans are lonely

It's hard to feel alone — and loneliness is harmful too.

Being lonely can disrupt sleep, increase stress and inflammation, and weaken a person's immune system. It's also associated with cognitive decline, heart disease, and greater frailty later on in life.

Recent research has found that this has such a significant effect on mortality rates that loneliness could be considered a public health threat that's more harmful than obesity and about as bad as smoking. According to a new survey by the health insurance company Cigna, the loneliness epidemic is so serious in the US that most American adults are considered lonely, with younger Generation Z and millennial Americans being the most lonely.

The new survey isn't the first to raise major concerns about the effects of loneliness in the US and around the world.

Two huge meta-analyses of studies on loneliness presented at last year's Annual Convention of the American Psychological Association showed the global scale of the problem.

"Indeed, many nations around the world now suggest we are facing a 'loneliness epidemic,'" Julianne Holt-Lunstad, a professor of psychology at Brigham Young University, said in a statement at the time. "The challenge we face now is what can be done about it."

But Cigna's new research raises additional concerns, as it shows both how widespread this issue is in the US and that young people may be particularly affected by the loneliness epidemic.

Most Americans are lonely

Along with research firm Ipsos, Cigna surveyed 20,000 US adults aged 18 or older to assess the state of loneliness. They used a questionnaire based on the UCLA Loneliness Scale, which is the measure most widely used by researchers to measure loneliness.

Possible loneliness scores ranged from 20 to 80 in the scale, with anything above 43 qualifying as "lonely." The average score was a 44, making most Americans qualify as lonely.

Just under half of respondents reported sometimes or always feeling alone or left out. About 27% of Americans said they feel that people rarely or never understand them. One-fifth of respondents said they rarely or never feel close to people, and just under half said they didn't have meaningful relationships or felt isolated.

Being around other people helps reduce loneliness, for the most part. People with regular meaningful in-person interactions reported less loneliness and better health, though only half of Americans had meaningful in-person interactions on a daily basis.

People who lived alone had an average loneliness score of 46.4, while those who lived with others had a an average score of 43.5. But single parents living with kids had an average score of 48.2, which suggests that having kids doesn't necessarily make people less lonely and that the pressure of supporting kids alone may have a negative effect.

Young people in particular reported high rates of loneliness, with rates gradually decreasing with age.

Perhaps surprisingly, social media use didn't seem to predict loneliness. Younger people also reported higher levels of shyness, while older adults reported feeling more outgoing.

Loneliness is an epidemic

Loneliness has a significant effect on health, which means that coming up with a way to reduce it could have a hugely positive impact.

In general, there's a strong link between physical and mental health. Loneliness seems to play into that link. People who felt the least lonely also were likely to get the right amount of sleep, exercise more, spend time with family, and have enough work without feeling overworked.

"We view a person's physical, mental and social health as being entirely connected," David Cordani, president and chief executive officer of Cigna, said in a statement. "In analyzing this closely, we're seeing a lack of human connection, which ultimately leads to a lack of vitality – or a disconnect between mind and body. We must change this trend by reframing the conversation to be about 'mental wellness' and 'vitality' to speak to our mental-physical connection. When the mind and body are treated as one, we see powerful results."

In Korea, Cigna has launched initiatives to have phone check-ins to reduce feelings of loneliness for some customers. Countries like the UK have hotlines seniors can call to speak with another person.

Psychologists say that individuals can also take steps to reduce loneliness. Individuals dealing with feelings of social isolation can retrain their approach to the world by finding simple social activities they enjoy and trying to expect the best, wrote Dr. John Cacioppo, a researcher who helped pioneer the field of social psychology.

But the widespread nature of the problem suggests that it's systematic and may require more of a widespread solution, as opposed to an individual one. With that in mind, the researchers behind the new study suggest that communities and workplaces could take a larger role in trying to combat loneliness.

Because as this growing field of research shows, people who feel lonely are not alone.