The Japanese have a word for it--karoshi, or "death by overwork." But can stress on the job really do you in? Finnish researchers decided to find out. The years 1991 to 1993 in Finland were as bad as it generally gets economically, with unemployment nearly tripling. Those who survived the downsizing had to assume greater work loads. During this period and for seven years afterward, Dr. Jussi Vahtera and psychologist Mika Kivimaki at the Finnish Institute of Occupational Health in Helsinki followed municipal workers who survived the cutbacks in four towns. Their sobering conclusion appeared this February in the British Medical Journal. Kivimaki puts it bluntly: "Those in work units with the most downsizing suffered twice the death rate from heart attack and stroke."

It should come as no surprise that emotions affect the heart--and not only in metaphorical terms. Suffer a fright, and your heart begins to pound. Get angry, and your blood pressure rises. Thirty years ago scientists told us that men with type A personalities--hard-charging, competitive and hostile--were more likely to suffer heart attacks. That turned out to be only partly true. Upon further investigation, anger and hostility were a problem, but not simple ambition or competitive drive. Today scientists are using high-tech instruments to elucidate the mind-body connections that damage the heart. And they are pointing the way to nonsurgical treatments that may benefit all of us.

If belligerence puts people at risk, science increasingly shows that a life of quiet desperation does, too. Patients who are depressed at the time of bypass surgery are more than twice as likely to die in the next five years as patients without clinical depression. Heart-attack survivors who live by themselves die at twice the rate of those who live with others. In a major study in the Lancet this month, researchers surveyed more than 11,000 heart-attack sufferers from 52 countries and found that in the year before their heart attacks, the patients had been under significantly more stress than some 13,000 healthy control subjects. "Severe stress didn't pose as great a risk as smoking," admits senior investigator Dr. Salim Yusuf of McMaster University. "But it was comparable to risk factors like hypertension and abdominal obesity. That's much greater than we thought before."

At every stage of heart disease, state of mind appears to play a role. It's most obvious in the later phases, where one can easily tally up heart attacks and deaths. But scientists are now showing that it plays a role in the initial phases as well. Psychologist Timothy Smith of the University of Utah is using CT scans to detect tiny calcium deposits in coronary arteries, an early sign of arterial damage. At the Society of Behavioral Medicine this year, he reported that couples with no history of heart trouble who were hostile or domineering in their interactions over money, kids, in-laws and household chores were more likely to have this type of damage. "The more strained their relationships, the more severe the silent atherosclerosis tended to be," he adds.

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If there's a common explanation for these various effects, it may lie in the stress response. The classic stress condition is the fight-or-flight syndrome. The heart shifts into high gear and blood pressure rises, as the body speeds delivery of oxygen and glucose to muscles. Platelets in the blood become more "sticky" to aid clotting in the case of a wound. That's perfect for emergencies. But when the body responds the same way to everyday stressors like honking horns and looming deadlines, the cardiovascular system suffers. Chronic high blood pressure damages blood vessels, leading to inflammation and plaque formation. Turbulent blood flow can rupture a plaque, with the resulting blood clot leading directly to a heart attack.

The implications are dramatic--not only for our risks of developing heart disease, but also for treating it. Along with low-fat diets and exercise, stress reduction should be an integral part of any program for healing heart health. Stress reducers like yoga, meditation and group sharing have direct effects on cardiac risk, lowering levels of stress hormones and helping to relax arteries. They also have indirect effects. Practitioners gain a sense of well-being that helps them stick to a diet and exercise plan. "Simply looking at the picture of someone you love can help dampen stress responses," says Smith in Utah.

It only goes to show, as the Bible says in Proverbs 17:22, "A cheerful heart is a good medicine." And that's reason for all of us to take heart.