12th July 2007

The BBC stumbled across an interesting story this week, according to a 30 year study by Chicago Northwestern University men who are shy or have few social interactions are 50% more likely to die of a heart attack, compared with men who are ‘the life and soul of the party.’ Whether regularly logging on to a social network makes up for a lack of real world interaction was not explained.

Research into the link between personality type and disease was also carried out in 2003 by the UCLA AIDS Institute. They discovered that the way people react to stress influences how easily they resist or succumb to disease, including viruses like HIV. UCLA AIDS Institute scientists pointed to an immune mechanism that makes shy people more susceptible to infection than outgoing people.

"During the AIDS epidemic, researchers found that introverted people got sick and died sooner than extroverted people," said Bruce Naliboff, co-author and a clinical professor at the UCLA Neuropsychiatric Institute and Veterans Affairs Greater Los Angeles Healthcare System. "Our study pinpoints the biological mechanism that connects personality and disease."

The UCLA team studied the effect of stress on viral replication in a group of 54 HIV infected men. All of the men were still in the early stages of the disease and in good health. Each possessed high T-cell counts with detectable levels of virus in the blood.

The researchers put each man through a series of stress tests in the lab to measure the response of their autonomic nervous system. First, the scientists monitored the subject's response to a tiny stimulus, such as an unexpected beeping sound. They measured his heart rate, skin moisture and dilation of the blood vessels, which contract during stress to reroute blood to the legs for fight or flight.

"Shy persons didn't adapt to the beeps as fast as other people," Cole said. "Their heightened nervous system response indicated that the sound was more irritating to them."

The Chicago researchers thought shy men might become stressed by new situations, or their personality type impacts on the part of the brain that controls the smooth operation of the heart.

In his book ‘Transforming Stress’ Doc Childre also highlights the impact the brain can have on the correct functioning of the heart. He also notes that the electronic signal produced by the heart is strong enough to be detected by the bodies of people standing close to each other. This seems to point to importance of physical proximity during social interaction. Childre is founder of HeartMath, a company that produces an ECG based device used to teach people to how to control their breathing and reduce the influence the brain has on the operation of the heart.

Darian Leader and David Corfield in their recent book ‘Why Do People Get Ill?’ - which examines the psychosomatic causes of illness - also highlight a lack of social interaction as a contributor to heart problems and a range of other diseases. They point out that people start life joined to a body – that of their mother – and even after they are born constantly interact with their mother. The book sees a correlation between external events, such as arguments, life style changes and bereavement and the onset of serious illness.

There seem few areas in this field that have not been thoroughly researched. However the fact that online social networking services such as FaceBook and MySpace are relatively new means that their role as a replacement for real life social interaction - and the consequent impact of the health of otherwise solitary people - is, as yet, largely unknown. Perhaps a publicity hungry professor or a university department seeking a DotCom sized research grant will soon be on the case.

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