"We've known for years that chronic stress leads to increased risk of premature death, even in the absence of other things it's connected with, such as not taking care of yourself, or high blood pressure," Franke explains. "Stress leads to your body producing cytokines or other inflammatory agents. In chronic stress, you carry on such responses to an abnormal extent, past what the fight-or-flight response was perhaps meant to handle, wearing down the body."
Chronic stress can cause excessive blood clotting, leading to blockages and strokes, Feltheimer says. "It also decreases the responsiveness of the immune system&. And with chronic stress, some cytokines can in essence degrade the structural stability of plaques lining blood vessels, which is analogous to making a blister more prone to popping, and so that can contribute to a heart attack if it does pop."
"People need to focus on things that are within their control. It's wasted energy to stress about things outside your control," Franke says. "Try to downshift and go with the flow, and if there are situations you can't downshift with, then avoid them if possible."
Charles Q. Choi is a frequent contributor to Scientific American. His work has also appeared in The New York Times, Science, Nature, Wired, and LiveScience, among others. In his spare time, he has traveled to all seven continents.