Friendship is good for you

"Without friends," Aristotle said, "no one would want to live, even if he had all other goods." It is not simply your mental health which benefits from a broad network of friends but your physical well-being. There is a big biological pay-off, it seems, to having a strong social circle. Friends can boost your defences against disease, help you heal, lower your blood pressure, improve your cholesterol and help you live longer in older age, says research.

The University of Michigan's Institute for Social Research says, "Social relationships or the relative lack of constitute a major risk factor for health - rivalling the effects of well-established health risk factors such as cigarette smoking, blood pressure, and obesity." So how do friends become life savers in the literal sense? Many studies have found that friends - the old-fashioned kind that you talk to on the phone, e-mail, or meet with in person - can improve your immune system.

They help you handle stress by reducing your production of the hormone cortisol, which has a negative effect on your mood and your body's natural defences. Practically speaking, when a friend accompanies you to a doctor's appointment or medical procedure, you're likely to experience lower blood pressure and a slower heart rate. And over the long-term, stress is then less likely to do you the kind of damage that can lead to chronic diseases such as heart disease and metabolic disorders.

The Ohio State University psychologist Janice Kiecolt-Glaser, who studies friendship and health, calls social support the most reliable psychological indicator of an improved immune response that has been found. Friends can also keep you fit, apparently, just by making you giggle. The professor Richard Wiseman, a psychologist at Hertfordshire University in the UK, said: "A good laugh increases your heart rate, helps you breathe more deeply, and stretches many different muscles in your face and upper body. It is like a mini work-out.

"One researcher estimated that a good laugh produces an increase in heart rate that is equivalent to 10 minutes on a rowing machine or 15 minutes on an exercise bike. "And, yes, one of the most important parts of the body's defences against disease and illness is its immune system. Experiments suggest that people who laugh more and are able to look on the funny side of life, have healthier immune systems than others."

Andrew Reeve, 48, a principal lecturer at Nottingham Trent University in England, said he gleaned huge benefits from his social network when he went through a particularly hard time: redundancy, his father's death, a split from his long-term girlfriend and the sale of the house they had bought together. "It was a hugely stressful time, perhaps the most stressful of my life," he said. "Disasters seemed to come by the truckload. People either go under or get stronger at times like this, and friends were crucial to me because they helped me keep things in perspective.

"A lot of my friends date back to school days. I'd talk to some about the relationship problems I was having, others about work. We'd go walking together, swimming, all of which probably stopped me eating too much. Workwise, it was a great boon because my friends had a network of other friends who I could tap into for advice, and who ultimately helped me retrain and get a new job." Studies show that feeling connected to others, like Andrew did, provides not only meaning and purpose, both of which are essential to the human condition, but also a positive physiological effect on the body in the way stress confers a negative one.

One of the most recent studies, carried out at the University of Birmingham in the UK in March, 2006, found that flu vaccination works less effectively in people more than 65 years old who have recently experienced the death of a relative or close friend than in those who are happily married. For women with breast cancer, social support is associated with a better outcome. Research by the University of California found that socially isolated women had a higher risk of dying after a diagnosis of breast cancer. In a study from Stanford University in the US, women with advanced breast cancer who attended a weekly support group lived twice as long as those who did not.

Another study by the University of California showed that women reacted to stress by producing brain chemicals that actually caused them to make and maintain friendships with other women. Apparently, when women enjoy a supportive friendship, more of the so-called "love hormone" oxytocin is released, which reduces stress and creates calm. Oxytocin is the hormone linked with attachment, connection, nurturing, bonding, and mothering.

This calming effect is not as effective in men because when men experience stress they produce high levels of testosterone, which reduces the effects of oxytocin rather then promotes it. Oestrogen levels in women enhance oxytocin release. But both men and women with a strong network of friends live longer, according to an Australian study that followed 1,500 people over the age of 70 for 10 years.

The research showed that having a group of good friends is even more important to living longer than having close family ties. Those who had a strong network of friends were 22 per cent less likely to die at a younger age than those with fewer friends. Researchers suggested that this could be because friends could influence a person's health, such as discouraging smoking, and could affect a person's mood, self-esteem, and ability to cope with a loss.

Surprisingly, spending time with an intimate partner doesn't provide the same health benefits as friendship. Researchers said good friends offered a different kind of support than spouses, siblings, parents, or children do. They provided a different level of understanding and communication, which positively affects health, wellness, and attitude. The feeling of being connected is another health benefit of friendship.

So good friends help you relax and boost the belief that things will turn out fine. Without social ties or friends, you're more likely to experience negative emotions, more illnesses, and even earlier death, it seems. So go ahead and plan that soiree, or phone call; it won't just be fun, it will be good for your health.