All of these studies, as well as our own Harvard Study, bear witness to the importance of human connections. They show that people who are more connected to family, to friends, and to community, are happier and physically healthier than people who are less well connected. People who are more isolated than they want to be find their health declining sooner than people who feel connected to others. Lonely people also live shorter lives. Sadly, this sense of disconnection from others is growing across the world. About one in four Americans report feeling lonely—more than sixty million people. In China, loneliness among older adults has markedly increased in recent years, and Great Britain has appointed a minister of loneliness to address what has become a major public health challenge.

2: Why Relationships Matter

“These feelings, big and small, are connected to biological processes. Just as our brain responds to the presence of food in our bellies by rewarding us with pleasure sensations, so does it respond to positive contact with others. The brain effectively says to us: Yes, more of this, please. Positive interaction tells our bodies that we are safe, reducing our physical arousal and increasing our sense of well-being. By contrast, negative experiences and interactions create a sense that we are in danger and stimulate us to produce stress hormones like adrenaline and cortisol. These hormones are part of a cascade of physical reactions that raise alertness and help us respond to situations of critical importance—the “fight or flight” response. They are a big part of what gives us that feeling of stress.

When you’re lonely, it hurts. And we don’t mean that metaphorically. It has a physical effect on the body. Loneliness is associated with being more sensitive to pain, suppression of the immune system, diminished brain function, and less effective sleep, making an already lonely person even more tired and irritable. Recent research has shown that for older people loneliness is twice as unhealthy as obesity, and chronic loneliness increases a person’s odds of death in any given year by 26 percent. A study in the U.K., the Environmental Risk (E-Risk) Longitudinal Twin Study, recently reported on the connections between loneliness and poorer health and selfcare in young adults. This ongoing study includes more than 2,200 people born in England and Wales in 1994 and 1995. When they were 18, the researchers asked them how lonely they were. Those who reported being lonelier were more likely to experience mental health problems, to engage in risky physical health behaviors, and to use more negative strategies to cope with stress. Add to this the fact that a tide of loneliness is flooding through modern societies, and we have a serious problem. Recent stats should make us take notice.

If we feel disconnected from others at work, that means we feel lonely for the majority of our waking hours. This is a health concern. As we’ve mentioned elsewhere, loneliness increases our risk of death as much as smoking or obesity. If we find ourselves feeling lonely at work, it may be up to us to create opportunities for social connection to the extent that we can. For parents raising their kids at home, play dates or visits to a local park (which are often as much for the parents as for the kids) can be restorative. For warehouse workers, there may be opportunities to connect with people directly before a shift, or directly after.

The power of friendship isn’t just the stuff of anecdotes or philosophical observation; science has clearly shown this effect. Friends diminish our perception of hardship—making us perceive adverse events as less stressful than we might otherwise see them—and even when we do experience extreme stress, friends can diminish its impact and duration. We feel the stress, but with the help of friends we’re better able to manage it. Less stress and better stress management lead to less wear and tear on our bodies.

Friends, in short, keep us healthier.

In Chapter Two we discussed a 2010 review conducted by Julianne Holt-Lunstad and others that brought together 148 studies and a vast amount of data to analyze the effect that social connections have on health and longevity. Among those 148 studies were a number that focused specifically on friendship. Here are a few that make the point:

• A large longitudinal study in Australia found that people over 70 with the strongest network of friends were 22 percent less likely to die during the study period (ten years) than those with the weakest network of friends

• A longitudinal study of 2,835 nurses with breast cancer found that women who had ten or more friends were four times more likely to survive than women who had no close friends.

• A longitudinal study of over 17,000 men and women between the ages of 29 and 74 in Sweden found that stronger social connections decreased the risk of dying from all causes by almost a fourth over a period of six years.