Despite its bad reputation, stress is one of our bodies' best defense systems. That's great if we're responding to a threat that requires physical action. Unfortunately, Dr. Dickstein says, our bodies don't recognize the difference between physical threats and mental ones. When we get nervous about meeting a deadline, for instance, we may produce the same stress chemicals as when we see that oncoming car. And if we don't burn off these chemicals through physical exertion, they can linger in the bloodstream and start causing problems.
Studies show that stress can reduce the power of our immune systems.
A study in Britain exposed 266 people, most of them in their thirties, to a common cold virus and then tracked who became sick. The study showed that 28.6 percent of those with few signs of stress caught the cold. But the figure jumped to 42.4 percent for those who were under high stress. Stress may inhibit the disease-fighting cells in our bloodstreams. But if you're under a lot of stress, a virus may get to you that you would have been able to fight off otherwise.