Cacioppo, an evolutionary psychologist who has studied social connection for 30 years, stresses that chronic loneliness has well-documented health effects. For decades, scientists have known that social isolation impacts our health in ways comparable to the effects of high blood pressure, lack of exercise, obesity and smoking. In short, being lonely is bad for you. But what Cacioppo and his colleagues have found is that it's not literally being alone, but the subjective experience known as loneliness that causes harm.
"Whether you're at home with your family, working in an office crowded with bright and attractive young people, touring Disneyland, or sitting alone in a fleabag hotel on the wrong side of town, chronic feelings of loneliness can drive a cascade of physiological events that actually accelerates the aging process," he writes.
While brief periods of loneliness, such as your first semester away at college, or following the death of your spouse, doesn't appear to cause grave harm, chronic loneliness does. The long-term lonely are likely to suffer more diseases at an earlier age, and die younger than those who feel close to others. By middle age, the lonely drink more alcohol, eat more fat and exercise less than their more social fellows. The experience of feeling lonely -- whether or not you're surrounded by family, friends and co-workers -- impacts stress hormones, immune function and heart health.