Socializing with others is good for one's health, both physical and mental, and we know this because researchers have been telling us so for years.

But what of social networking on the computer on sites like MySpace, where we chat it up with invisible souls we most likely will never meet? Is that good or bad for our health?

Bad, it turns out, potentially very bad. So bad it could lead to cancer, high blood pressure, strokes and dementia.

That's the contention of one British researcher in an early study into the health effects of social networking.

Dr. Aric Sigman contends these potentially dire consequences are the price people may be paying for cutting down on the amount of time they spend with others face to face while increasing the time they spend socializing in the virtual world.

“It is clear that this is a growing public health issue for all industrialized countries. Children are now experiencing less social interaction and have fewer social connections during key stages of their physiological, emotional and social development,” writes Sigman in an article published in today’s issue of the Biologist, the journal of Britain’s Institute of Biology.

Social networking has gone from being unknown to being commonplace in just a few years, and that rapid rise in popularity has left scientists scrambling to figure out just what the consequences are of people devoting so much of their time communicating with people through computers.

Dr. Sigman believes that while these networks are intended to boost friendships, they are actually reducing the amount people socialize in the real world.

He says that the number of hours a day that Britons spend in social interactions in the face-to-face world has dropped from six in 1987 to just over two in 2007. Over that period, the number of hours Britons spend using electronic media has climbed from just under four hours a day to over eight.

On top of this, the electronic age also means more people work home alone and parents spend less time with their plugged-in children. This is one of the key factors behind a major change in British society, he says.

“One of the most pronounced changes in the daily habits of British citizens is a reduction in the number of minutes per day that they interact with another human being. In less than two decades, the number of people saying that there is no one with whom they can discuss important matters nearly tripled,” says Dr. Sigman, who is a member of the Institute of Biology and a Fellow of the Royal Society of Medicine.

He believes the face-to-face interaction has actual hormonal effects on the body, such as stimulating the release of oxytocin and other things that help activate the immune system.

The lack of such interaction has the opposite effects.

He points to studies showing that women with fewer friends suffer strokes at more than twice the rate of those with more friends. He also says that loneliness – or a lack of it -- can influence blood pressure.

He claims that the amount of social contact may influence cognitive function. In fact, just 10 minutes of social interaction can boost cognitive function. Social interaction may even help protect against dementia and memory loss. In fact, there are a number of other areas where he says social interaction can have an impact.

“Social connection, both objective and subjective, is increasingly associated with physiological changes known to influence morbidity and mortality,” he writes. “However, the intricate mechanisms involved are only now being understood.”