Alan Alda in Scientific American Frontier's Worried Sick

Angry at heart Wild macaque monkeys live in large groups where constant and stressful competition establishes the social hierarchy. The relationships among the monkeys are not random, but are determined by each animal's personality. In "Angry at Heart," at Wake Forest University in North Carolina, Jay Kaplan makes use of macaques' natural tendency to compete to investigate the relationship among personality, stress and cardiovascular disease. Stressed-out monkeys develop twice the atherosclerosis as subordinate animals.   In a series of long term experiments, Kaplan places small groups of male macaques-all strangers to each other-in a cage together. While the macaques establish who is dominant and who is subordinate, Kaplan keeps tabs on each monkey's stress hormone levels. A surprising fact emerges: it's not the subordinate, but dominant males that feel more stress. Kaplan fed the monkeys nutritious diets but including one third fat-about the same as the average American eats-and regularly checked their cardiovascular systems. Over the course of the experiments the dominant, stressed-out macaques developed twice the atherosclerosis as the subordinate animals. Kaplan suspects the frequent surges in heart rate and blood pressure brought on by stress are enough to damage the more aggressive animals' arteries and allow artery-clogging plaques to build up.   Stress has a greater physical impact on hostile people than on less agressive people.   What about in humans? Researchers have been looking for a personality trait that predicts cardiovascular health for 30 years. Duke University psychiatrist Redford Williams thinks he's found one: hostility. Using personality tests dating back to the 1950s, Williams was able to establish a link between hostility and poor health. People who had high hostility scores were two to three times more likely to develop heart disease in subsequent years. In one study, the most hostile were seven times more likely to die.   In Williams' lab, experimental subjects Terry and Carlton demonstrate the difference between high and low hostile people. When Terry recalls an episode that really makes her mad, her blood pressure and heart rate increase somewhat. But when Carlton thinks about an upsetting memory, his vital signs soar -- probably damaging his arteries in the process. "It's as though they are wired in a different way," says Redford Williams. Need more evidence that psychological stress can affect your physical well-being? Thousands of heart patients require defibrillators, implanted electronic devices that monitor patients' heart rhythms, then deliver restorative shocks when appropriate, as well as recording everything they do. In the wake of the September 11th terrorist attacks, cardiologist Jonathan Steinberg looked at the records from 200 patients. He found a two and half fold increase in defibrillator activity. All this evidence makes it clear that stress is a major risk to cardiovascular health. For more on this topic at the PBS site, see the feature: What's Your Type?   Running for the Shelter   or close window