Why Loneliness Is Bad for Your Health

A conversation with John Cacioppo, author of a new book on the need for social connection.

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When all is said and done, the best guarantee of a long and healthy life may be the connections you have with other people. John Cacioppo, a neuroscientist at the University of Chicago and coauthor of a new book, Loneliness: Human Nature and the Need for Social Connection (W. W. Norton, $25.95), talked with U.S. News about the latest research on how relationships affect physical health. Edited excerpts:

Why did you choose to study loneliness?

We want to understand what importance our social connections have to people's biology. Early in human history, our species's survival required the protection of families and tribes. Isolation meant death. The painful feeling known as loneliness is a prompt to reconnect to others. You say that social isolation has an impact on health comparable to high blood pressure, obesity, lack of exercise, or smoking. Can you explain?

Loneliness shows up in measurements of stress hormones, immune function, and cardiovascular function. Lonely adults consume more alcohol and get less exercise than those who are not lonely. Their diet is higher in fat, their sleep is less efficient, and they report more daytime fatigue. Loneliness also disrupts the regulation of cellular processes deep within the body, predisposing us to premature aging. You point out that, oddly enough, loneliness also makes us less socially adept. How?

Lonely adults have the same social skills as nonlonely adults, but they don't deploy them as appropriately. We think that lonely individuals feel threatened, and because of that feeling of threat, they're not certain they can trust others. When you see something positive happening to others, you're not sure if you're included, so you're aloof, demanding, or critical. Is the solution to surround ourselves with people?

Loneliness isn't necessarily a result of being alone. Think about a bereaved spouse and the college freshman going away from home for the first time. They can be around a lot of people but feel completely isolated. In humans, perceived isolation is so much more important than physical isolation. How can each of us manage our own feelings of loneliness?

Just like hunger and thirst and pain, loneliness signals something important for the survival of your genes—the need for connection to other individuals. A loneliness response might tell you to pass up that promotion that requires that you rip yourself away from friends and family and move to another country. Or if you do move, you'll know you have to say, OK, I will set up a system to maintain and restore those relationships. In everyday life, play with the idea of trying to get small doses of the positive sensations that come from good social interactions. Just saying to someone, "Isn't it a beautiful day?" or "I loved that book!" can bring a friendly response that makes you feel better.

When it comes to friendships, some people think that in order to be less lonely, everybody has to like them. That's not true. It takes just one, two, or three people. The person who has 4,000 friends on Facebook is not necessarily the least lonely person, especially if he spends all his time maintaining his Facebook page.

I'm glad you brought up Facebook. Can virtual connections give us what we need?

It really depends how one uses them. People have thought of them as being all good or all bad, but it's more subtle than that. If you use artificial means of connecting as a substitute for physical means of connection, you actually get lonelier. However, if you are disabled and isolated by virtue of the disability and the Internet is permitting you to make connections, then it decreases feelings of isolation. You say we connect with others in three basic ways, but each person has his or her own comfort level with those connections. How does that work?

Humans have a need to be affirmed up close and personal; we see this most often in marriage. But people who don't marry may find meaning elsewhere. We also have a need for a wider circle of friends and family, but we all know that close family connections can be a mixed blessing. And there's a need to feel that we belong to a larger group. Many of us tend to ignore the collective part of social connection until there is an insult or threat. An example is how, right after 9/11, Americans felt very close to one another. There was a harmony and helpfulness that was really quite surprising. Being an Obama-ite during the campaign would be another example of having a collective identity, feeling like you're part of something grand and wonderful.

Corrected on : Updated on 11/14/2008