The Ways Loneliness Could Be Changing Your Brain and Body

People were already alone before the coronavirus pandemic blow. Before COVID-19 left people stuck at home and made approaching others an unnerving experience, researchers were realizing that Americans were lonelier than ever.

A 2018 study by health insurer Cigna found that 54% of 20,000 Americans surveyed reported feeling lonely. In just over a year, the number has risen to 61%. Gen Z adults aged 18-22 are reportedly the loneliest generation, outperforming Boomers, Gen X and Millennials despite being more connected than ever.

Loneliness has reached epidemic proportions, said Doug Nemecek, medical director at Cigna.

More worryingly, a growing body of research suggests that being alone for an extended period of time can be bad for people’s physical and mental well-being.

That same Cigna study posed the health risks associated with smoking and obesity.

A 2018 article in The Lancet described the situation like this: “Imagine a condition that makes a person irritable, depressed and self-centered, and is associated with a 26% increased risk of premature mortality.”

But these are strange times. As a result of COVID-19, keeping your distance from others is the safest way to stay healthy, although it can exacerbate feelings of isolation. It’s a new reason to consider how loneliness can affect everything from the brain, heart and immune system.

Why do we get lonely

Loneliness can conjure up images of being away from friends and family, but the feeling runs much deeper than having no plans on a Friday night or going to a wedding. Evolutionarily, being part of a group has meant protection, sharing the workload, and increasing the chances of survival. After all, humans take a long time to mature. We need our tribes.

“It’s very distressing when you’re not part of a group,” said Julianne Holt-Lundstad, a professor of psychology and neuroscience at Brigham Young University. “We have to deal with our environment entirely on our own, without the help of others, which puts our brain on alert, but also signals that the rest of the body is on alert.”

Remaining in this state of alertness, in this high state of stress, means wear and tear on the body. Stress hormones like cortisol and norepinephrine can contribute to insomnia, weight gain, and anxiety over long periods of exposure, according to the Mayo Clinic.

The pandemic, Holt-Lundstad pointed out, is possibly the most stressful experience many people have had in their lives. Everyday life has been altered, unemployment has soared and more than 6 million people worldwide have been infected. Typically, overwhelming challenges like these would cause you to seek reassurance and support from family and friends. But due to the nature of the virus, people are at least more physically alone than ever before, making it that much harder to deal with.

studying loneliness

Loneliness is something almost everyone can relate to, but scientists are still working to understand how and why it affects health. One of the fundamental challenges of the research: loneliness is a subjective feeling that really cannot be measured. Not even the size of a person’s social network can guarantee how lonely they are.

Holt-Lundstad said it’s a matter of asking people how they feel in polls, either directly (how often would you say you’re alone?) or indirectly (do you miss companionship?).

NASA has studied the effects of isolation and confinement on astronauts for years, coming to some of the same conclusions as countless other studies: Isolation conditions can lead to cognitive and behavioral problems. Elsewhere, though, researchers are looking at the biological aspects of loneliness and how it physically affects the body.

That might mean looking at brains.

Researchers at Rush Alzheimer’s Disease Center in Chicago studied 823 seniors over a four-year period. They used questionnaires to assess loneliness, dementia and Alzheimer’s disease ratings, as well as tests of participants’ thinking, learning, and memory, and assigned a loneliness score between 1 and 5. They found that a person’s risk factor for Alzheimer’s disease increased by 51% for each point on the scale.

Autopsies were performed on those who died during the study. Loneliness has not been shown to cause the “characteristic brain changes associated with Alzheimer’s disease, including nerve plaques and tangles, or tissue damaged from lack of blood flow.” However, a researcher involved in the study, Robert S. Wilson, said that loneliness can make people more vulnerable to the “damaging effects of age-related neuropathology”.

“Loneliness [can] be a good predictor of accelerated cognitive decline,” said Turhan Canli, professor of integrative neuroscience at Stony Brook University.


Scientists are looking at loneliness and gene expression.

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How exactly loneliness relates to poor health is not fully understood. One idea, Canli said, is that if someone is lonely and feeling bad about themselves, they may be less likely to take care of themselves. They might not eat right. They may drink too much, worry too much, sleep too little. Habits like these can have long-term effects.

Canli also talked about work he’s been involved in with another researcher at Rush Alzheimer’s Disease Center, David Bennett, who explores how different genes are expressed in people who are and are not lonely.

About 30 years ago, Bennett began a longitudinal study whose participants agreed not only to annual physical and psychological exams, but also to donate their brains when they died. The researchers analyzed two brain regions related to cognition and emotion. They found genes associated with cancer, cardiovascular disease and inflammatory disease expressed in those who were most lonely.

“Actually, there is a network of connections between these different genes by which they can affect each other,” Canli said, “which could be an underlying genetic reason why these diseases can appear as a result of loneliness.”

This is not to say that loneliness causes heart disease. There is more research to be done, including the role that heredity plays in gene expression. Previous work by a UCLA researcher named Steve Cole has suggested one possibility – that the release of certain hormones under the stress of sustained loneliness could be turning on certain genes linked to poor health.

“Subjective experience has to be translated somehow in the brain into biology, and that’s what we’re seeing now,” said Canli.

A better understanding of these relationships may one day influence therapies designed to treat patients.

the future of loneliness

Even as states are starting to relax lockdown orders and restrictions on restaurants, bars and other public places, the role social distancing can play in society is unknown. In April, Harvard researchers said intermittent social distancing could be necessary by 2022.

NASA astronaut Scott Kelly, who spent 340 days in space, wrote an article for The New York Times in March, offering advice based on his experience. Kelly recommends keeping a journal, following a schedule, and having a hobby.

Cigna’s Nemeck noted that now, more than ever, it’s more important to check in with others and be open to honest conversations about feelings of loneliness, while combating the stigma associated with the feeling.

“We need to reach out to some friends and make sure we keep those connections and have meaningful conversations,” he said. “It’s important that we all feel comfortable asking other people how they feel.”

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