Feb. 19 (Bloomberg) -- Social networking Web sites such as Facebook and MySpace may increase the risk of health problems as serious as cancer, strokes and dementia by altering the way genes work, according to a report in the Biologist journal.

The number of minutes per day Britons interact with other humans has fallen by two thirds in recent decades, from six hours in 1987 to two hours in 2007, Aric Sigman wrote in Biologist, the journal of the U.K.’s Institute of Biology.

At the same time, the amount of time people of all ages spend doing things that remove them from physical interaction like watching television, listening to iPods, playing video games or visiting Web sites, has doubled to eight hours a day, said Sigman, a fellow of the Royal Society of Medicine and associate fellow of the British Psychological Society.

The lack of “real” interaction combined wi1th a dependence on technology is increasingly tied to physiological changes known to influence morbidity, or the extent of disease, and mortality, according to the article, which collates data from western industrialized societies. Those changes include upsetting hormone levels, immune responses and blood pressure, the function of arteries and mental performance.

For example, Sigman looked at studies of women at risk of cardiovascular disease and found those with larger social circles had wider arteries and those with smaller social circles had narrower arteries and twice the death rate. All studies show the same pattern, he said.

“We probably have an evolutionary protective mechanism and when we were still in the cave, we would survive so much easier when we worked together,” Sigman said in a telephone interview. “Evolution has a system that benefits us when we connect with other people in the flesh.”

National Debate

The researcher called for a national debate on these issues, and said attention needed to focus on where younger generations are headed.

The Internet and other electronic media “can be fantastic tools but they shouldn’t displace real relationships,” he said. “The balance is all wrong.”

Britons spend about 50 minutes a day interacting socially with other people, according to Sigman’s article, entitled “Well Connected? The Biological Implications of ‘Social Networking.”

Couples spend less time with each other and more time at work, commuting, or in separate rooms of the same house using electronic media devices, and Britain has the lowest proportion of children in Europe who eat with their parents at the table.

Britons are in good company, Sigman said, as Americans are also stepping back from one another in unprecedented magnitude.

To contact the reporter on this story: Caroline Alexander in London at calexander1@bloomberg.net.

Last Updated: February 19, 2009 10:41 EST