Scientists have found that a long-term feeling of extreme loneliness can be deadlier for older people than being severely overweight.

Researchers from the University of Chicago have demonstrated that extreme loneliness and feelings of isolation can be twice as unhealthy as obesity for older people. The scientists tracked more than 2,000 people aged 50 and over for more than six years. Compared with the average person in the study, those who reported being lonely had a 14 percent greater risk of dying. Poverty increased the risk of an early death by 19 percent.

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The findings come at a critical point, as life expectancy has risen and people increasingly live alone or far from their families. A 2012 study of loneliness in older Britons found that more than a fifth felt lonely all the time, and a quarter became more lonely over five years.

This isolation is having a serious effect on both mental and physical health. At any given time, between 20 and 40 percent of older adults feel lonely, particularly during retirement, according to some studies.

Professor John Cacioppo of the University of Chicago Department of Psychology said that there was a noted difference in the rate of decline in physical and mental health as people aged, and that these differences could be linked to the number of satisfying relationships they maintain.

“We have mythic notions of retirement,” Cacioppo said. “We think that retirement means leaving friends and family, and buying a place down in Florida, where it is warm, and living happily ever after. But that’s probably not the best idea. Retiring to Florida to live in a warmer climate among strangers isn’t necessarily a good idea if it means you are disconnected from the people who mean the most to you.”

According to Cacioppo, many studies prove that people who stayed close to colleagues after retirement and maintained close friendships are less lonely.

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In a related study also conducted by the University of Chicago and published in Psychology and Aging, researchers found a direct relation between chronic feelings of loneliness and increases in blood pressure.

The research team studied 229 people aged 50 to 68 over a five-year period. Members of the group were asked to rate their connections with others, through statements such as “I have a lot in common with the people around me” and “I can find companionship when I want it.”

During the study, researchers, including Louise Hawkley, senior research scientist with the Center for Cognitive and Social Neuroscience, found a clear connection between feelings of loneliness reported at the beginning of the study and rising blood pressure.

“The increase associated with loneliness wasn’t observable until two years into the study, but then continued to increase until four years later,” reported Hawkley.

The increase affected even people with modest levels of loneliness, according to the study’s findings. Among all the people in the sample, the loneliest people saw their blood pressure go up by 14.4 millimeters more than the blood pressure of their most socially contented counterparts over the four-year study period.

Fear about social connections may be one reason for the blood pressure increase in lonely people.

“Loneliness is characterized by a motivational impulse to connect with others but also a fear of negative evaluation, rejection, and disappointment,” said Hawkley. “We hypothesize that threats to one’s sense of safety and security with others are toxic components of loneliness, and that hypervigilance for social threat may contribute to alterations in physiological functioning, including elevated blood pressure.”

“People are becoming more isolated, and this health problem is likely to grow,” said Cacioppo.

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To determine the most effective method for reducing loneliness, Cacioppo and a team of researchers from the University of Chicago examined the long history of research on the topic. Published in the journal Personality and Social Psychology Review, their quantitative review found that the best interventions targeted social cognition rather than social skills or opportunities for social interaction.

“We’re getting a better understanding of loneliness—that it’s more of a cognitive issue and is subject to change,” said Christopher Masi, M.D., assistant professor of medicine at the University of Chicago Medical Center and lead author of the study.

This means that stopping or preventing loneliness isn’t merely a matter of providing more people to interact with. Teaching lonely people to break cycles of negative thoughts about self-worth and how people perceive them was more effective.

Studies that used cognitive-behavioral therapy—a technique also used for treating depression, eating disorders, and other problems—were found to be particularly effective, the authors reported.

“Effective interventions are not so much about providing others with whom people can interact … as they are about changing how people who feel lonely perceive, think about, and act toward other people,” Cacioppo said.

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Despite previous findings that favored group formats, the current review found no advantage for either group or individual interventions.

“That’s not that surprising, because bringing a bunch of lonely people together is not expected to work if you understand the root causes of loneliness,” Masi said. “Several studies have shown that lonely people have incorrect assumptions about themselves and about how other people perceive them. If you bring them all together, it’s like bringing people with abnormal perceptions together, and they’re not necessarily going to click.”