We all know of the bitter sweet nature of friendships, but did you know that your friendships may actually be the key to a longer life?

A study has shown that your mates may contribute to a longer life and being sociable is good for your health, while loneliness is as bad for you as smoking 15 cigarettes a day.

A close-knit circle of friends and an active social life can boost your health. While your doctor may disapprove of the associated health risks of socialising – late nights, booze and social smoking – the repeat prescription of amigos and good conversation isn’t a hard pill to swallow.

Brigham Young University in Utah found close friends and strong family ties can boost a person’s health more than exercise, losing weight or quitting cigarettes and alcohol.

It also said being social brings us added rewards in addition to lowering stress levels. When someone is connected to a group and feels responsibility to other people, that sense of purpose and meaning translates to taking better care of themselves and taking fewer risks,’ says Julianne Holt-Lunstad, a psychologist at Brigham Young University.

The impact of personal relationships found a 50 percent better survival rate if those studies belonged to a wider social group, be it friends, neighbours, relatives or a happy medley of the above.

The notion has led researchers to call on GPs and health officials to take loneliness as seriously as other health risks such as alcoholism and smoking.

Trends such as increasing numbers of people living alone and the advent of new technologies are changing the way in which we interact and often lead people to experience loneliness. ’We take relationships for granted as humans,’ said Holt-Lunstad. ‘That constant interaction is not only beneficial psychologically but also directly linked to our physical health.’

The study, reported in the journal Plos Medicine, reviewed 148 studies that tracked the social interactions and health of 308,849 people over an average of 7.5 years. From these they worked out how death rates varied depending on how sociable a person was.

Holt-Lunstad said there was no clear figure on how many relationships are enough to boost a person’s health, but people fared better when they rarely felt lonely and were close to a group of friends, had good family contact and had someone they could rely on and confide in.

The dangers of smoking, diet and exercise are all taken seriously, and perhaps now social relationships can be added to the list – mind you, added to this and not as a replacement.