Several years ago at a party, a friend began telling me about how his father had died. I sat and listened, wishing I could be anywhere but in that chair; days earlier I'd passed the difficult twentieth anniversary of my own mother's death. My best friend, Ann, stood nearby listening and without saying a word, put her hand on my shoulder. It was a moment I will never forget: the clear nonverbal communication of someone who knows all the bad stuff, all the good stuff, all the history and who not only loves you but understands you in a way that doesn't need exposition.

Such friendships may be rare, but even for those that end abruptly, researchers are discovering that social connections are important not only for helping us through tough times: Evidence now suggests that friends may also offer physical health benefits.

Bert Uchino, Ph.D., professor of psychology at the University of Utah, studied how social support affects cardiovascular health, particularly in older adults. Uchino found that "social support moderated age-related differences in blood pressure and predicted higher resting blood pressure for individuals low in social support." The study claims that people around 50 years or older who had many social outlets had nearly identical blood pressure to those who were significantly younger—by decades.

"Social relationships serve important functions in our everyday lives," Uchino says. "Biomedical research indicates that supportive relationships really may significantly protect us from different types of mortality, like cardiovascular disease, cancer, and infectious diseases." In fact, his report claims that social connections may have the same health benefits for people as quitting smoking or increased exercise does.

One fairly obvious reason that researchers like Uchino link social support to good health is that having good friends often results in lower levels of stress. "Social support protects individuals from the negative physical consequences of stress," says Uchino, "and stress has long been linked to poorer health behaviors. Often social support directly motivates individuals to engage in healthier practices."

Bob Putnam, Ph.D., professor of public policy at Harvard University and author of Bowling Alone: The Collapse and Revival of American Community, says that in general Americans have stopped connecting with each other over the past 30 years for three main reasons: television, two-career families, and the expansion of cities. "Television is the only leisure activity where doing more of it is associated with lower social capital," he says.

Surprisingly, Putnam does not cite the Internet as one of the main culprits. "Bill Gates was in grade school when this trend began," he said, "and it's not clear yet whether the Internet will make this better or worse, so we can [still] make it part of the solution rather than the problem."

Putnam claims that your chances of dying early are cut in half by joining just one social group; by a quarter, if you join two groups. "If you smoke," he says, "it's a close call if you'd be better off quitting or joining a group." And further, if we all had a choice between 10 percent more police presence on our streets and 10 percent more folks knowing their neighbors, Putnam says the latter is a better crime prevention strategy.

One reason people today seem less connected, Putnam claims, has to do with women joining the workforce. "In past years, many women were the family's main means of social connection. Our moms were doing the social connecting. The guys haven't picked up the slack," he says. "The workplace hasn't changed the way it needs to in order to reconcile the obligations of job with community and family. This means flex time or release time. We're paying a price in how our families and communities are getting along.

"In the end, it comes down to people deciding that it's really good for your health to go on a [group] picnic this weekend," says Putnam. "There are actual physiological effects from connecting to other people. In a sense, having friends is like taking a very powerful multivitamin."