Love can bring out the best and worst in people, and a growing body of research is finding that love can also play a critical role in the health of couples. Last month, a study from the University of Utah in the US looked at the effect of a four- to seven-day separation on the health and well-being of 34 co-habitating couples. The tracking included testing the couples' saliva for cortisol, a hormone associated with stress. The research team, led by Professor Lisa Diamond of the psychology department, found that physical separations increased cortisol levels and had negative impacts on their sleep and level of positive interactions. 'During separations, only lengthy phone calls appeared to 'stand in' for contact,' says Diamond, whose work focuses on the nature and development of affectional bonds. 'The findings can contribute to our emerging understanding of the processes through which long-standing romantic ties are beneficial for our health.' Linda Lee, a Hong Kong resident and retired information technology professional who has just celebrated her 17th wedding anniversary, says she leads an active lifestyle as a result of her marriage. She and her husband share many common interests, such as dancing, golf, tennis, skiing and hiking. On the flip side, a divorc?e and finance professional who declined to be named says she drank more alcohol during her marriage. 'It took a few years before I realised the implications of being in that relationship,' she says. It is well-documented that married people tend to be healthier than unmarried people. According to Hui Liu, an assistant professor and sociologist at Michigan State University in the US, there are two theories for this. One is that being married gives you more access to social support and economic resources. The other is that being divorced or widowed hurts health. But a study led by Liu that was published in the September 2008 issue of the Journal of Health and Social Behavior found that the gap between the married and unmarried is narrowing, arguably due to changing marriage trends. Citing data from the US National Health Interview Survey, she found that health has improved for unmarried men in particular, perhaps due to better access to social resources and support that traditionally came from spouses. In Hong Kong, marriage rates have declined in the past 10 years, and people are marrying later, while non-marriage and divorce rates are increasing, according to statistics released last month by the Census and Statistics Department. Professor Grant Evans, an anthropologist at the University of Hong Kong, says this is the first time in recent history that he has witnessed a growing non-marriage rate in the city that is higher than that in the West. Yet it seems perceptions on marriage are positive. In a study titled 'Trends in Family Attitudes and Values' led by HKU Professor Nelson Chow, 1,000 Hong Kong residents in Sham Shui Po, Shau Kei Wan and Tin Shui Wai were surveyed and it was found that in 1993 only 26.7 per cent believed that married people were happier than unmarried people; in 2006 the figure rose to 39 per cent. 'Married people seem to be happier simply because they start off in a better mental state, enjoy mutual psychological support, and develop a meaningful, trusting relationship, which allows them to develop good communication and social skills, allowing them to solve conflicts and maintain other relationships,' says Samson Tse Shu-ki, associate professor at the HKU's department of social work and social administration. Counselling psychologist Catriona Rogers points out that marriages can be blissful if the couple communicates in a positive way. She cites research by Dr John Gottman, a leading US researcher on marriage and parenting, which shows that to build and maintain a good relationship, there needs to be five times more positive communication than negative - criticism, contempt, defensiveness and stonewalling - or it will end in unhappiness and divorce. However, having companionship - whether with a spouse, partner or friend - could also go in the other direction, encouraging gambling and addictions. A recent study by Dalhousie University, a Canadian school in Halifax, Nova Scotia, has found binge drinking can be contagious between romantic partners. The researchers looked at 208 unmarried heterosexual dating couples in their early 20s who had face-to-face contact at least five days a week and had dated for at least three months and an average of close to two years. Over the 28 days, the researchers found that they were able to predict one partner's binge drinking based on the other partner's binge drinking. 'In some respects, this is a cautionary piece of research,' notes Simon Sherry, an assistant professor in the university's psychology department. 'Pick your friends and lovers carefully because they influence you more than you think.' If you're interested in adopting healthier habits, new research by Massachusetts Institute of Technology suggests you'll have a better chance of success if you find a friend with similar traits to share the experience. In the internet-based study, published in December in the journal Science, participants paired with others of similar body mass, age, fitness level and diet preferences were three times as likely to adopt healthy behaviour as those matched randomly. Whether married or single, it's important to surround yourself with healthy social relationships. They can be as important as not smoking when it comes to your lifespan, and can result in a 50 per cent greater likelihood of survival than those with poor or insufficient social relationships. This is according to a study of 308,849 individuals over 7 1/2 years published in PLoS Medicine in July 2010 by researchers from Brigham Young University in Utah and the University of North Carolina in Chapel Hill. The authors of the study note the importance of these results even for babies' life expectancies. In the mid-20th century, mortality rates for infants in orphanages were substantially decreased with changes in practice and policy to promote social interaction. They note that medical professionals were stunned to learn that infants would die without social interaction. To conclude, they make a compelling case for social relationships to be added to the list of risk factors such as diet, exercise and smoking, and suggest making it part of medical evaluations and screenings. They infer that medical care could recommend enhanced social connections; hospitals could involve patient support networks in treatment regimens, and health care policies could likewise benefit from accounting for social factors in efforts aimed at reducing mortality risk.