Animals with an innate phobia of novelty have higher levels of stress hormones after a new experience and die significantly younger than their braver kin, new research has found. The work suggests that a lifetime of fearful stress can take an accumulated toll on health."It shows we need to consider personality traits and behavioural styles when trying to understand physiological mechanisms of health," says Sonia Cavigelli at the University of Chicago, Illinois, who conducted the study with her colleague Martha McClintock.Stress is known to have many effects on health including triggering brain cell loss and reducing fertility. But it is also known in some cases to enhance the immune response for inflammation. So the lifelong effects on stress on an individual are difficult to gauge.

The very personalised nature of stress started to intrigue Cavigelli when she was studying primates in the wild. "I saw many animals exposed to the same stressful stimulus, but they responded very differently," she told New Scientist. So she decided to study the health effects of neophobia - the fear of new things - in rats, a more easily managed animal.

"This is a critically important piece of research," says Michael Meaney, who researches how early experience affects behaviour and health at McGill University in Montreal, Canada. "We knew a lot about individual neophobia differences and health outcomes, but no one ever looked at lifespan. This fills in a key piece of the puzzle."


View: Full Article | Source: New Scientist