The links between the heart and mind are harder to quantify than those between the heart and the waistline, but most authorities think that psychological factors are—literally—heartfelt and can contribute to cardiac risk. Psychological stress, anger, social isolation, and depression are often related—people who have one commonly have another.

Evidence suggests that such problems can increase the risk for coronary artery disease and the risk of dying after a heart attack. Psychological stress can raise blood pressure, reduce blood flow to the heart, decrease the heart’s pumping ability, trigger abnormal pumping rhythms, and activate the blood’s clotting system.

Even a less extreme stressor, such as loneliness, seems to influence blood pressure, according to a 2002 study in the journal Psychosomatic Medicine. When researchers measured the blood pressure of eighty-nine students during a stressful test-taking experiment, those who had reported that they were lonely had increased blood pressure due to greater constriction of their arteries, which can be harmful in the long term.

Those who weren’t lonely had increased blood pressure due to increased cardiac output (more blood pumped out by the heart), a more normal stress response. Interestingly, it’s the way you react to stress rather than the stress itself that can be dangerous to your heart.

Some people take life’s stresses in stride, while others are more likely to become upset and angry. People who tend to be angry by temperament have strong emotional reactions when under stress and often overreact in ordinary circumstances as well.

A 2001 study in the American Journal of Epidemiology found that having a fiery personality was as strong a risk factor for heart disease as high blood pressure. The study, which included 12,990 middle-aged men and women, assessed the participants’ overall health and used a psychological questionnaire to identify those with angry temperaments.

Over the next three to six years, people who had angry temperaments had a risk for heart disease two and a half times greater than that of their more laid-back counterparts. The increase in risk was comparable to that of having high blood pressure. It’s important to note that it’s very hard to conduct stress studies well.

Measurements of anxiety and temperament are simply much harder to quantify than cholesterol level or body weight. Measurement of stress levels often involves some subjective judgment on the part of the study participant or the researcher.

That’s not to say that the evidence on stress’s effect on your heart (or other body parts) is wrong, but it is the kind of evidence that may be refined as better research tools make it possible to evaluate human psychology with greater precision.

As for depression, a study of 5,007 women and 2,886 men found that depressed women had a 73 percent greater risk of developing coronary artery disease than women who weren’t depressed—and that depressed men were 71 percent more likely to develop coronary artery disease than men who weren’t depressed.

Although the depressed women weren’t at an increased risk of dying from heart disease, the depressed men were 2.3 times more likely to die from it than men who weren’t depressed. Other studies have shown that lingering depression is a strong predictor of second heart attacks.

The relationship between depression and heart disease is a two-way street. Depression may not only promote but also be a product of heart attack. For as many as a third of people, depression follows a heart attack. Whether you’ve had a heart attack or not, if you feel depressed, tell your doctor.

Depression can be treated successfully with antidepressants, psychosocial therapy, or both. Treating depression can make you feel better, and studies are under way to see whether effective treatment for depression can prevent or reverse heart problems or extend life.

A study from Canada showed that strong social support blunts the relationship between depression and the risk of dying after a heart attack. It could be that social ties reduce the risk of dying by helping to relieve depression.

But another benefit could be purely practical: people with strong social support have more friends and relatives to encourage them to take their medications, exercise, and lose weight. Some careful studies suggest that stress-reduction techniques may help lower blood pressure and reduce the risk for recurrent heart attacks.

Some or all of the following approaches can help:

• Physical exercise. Aerobic exercise can actually dissipate stress and help control depression. Vigorous exercise stimulates the body’s production of natural chemicals that elevate mood and diminish pain.

• Behavioral changes. You can reduce your stress level by identifying the tasks, situations, and relationships that cause you undue stress and then modifying them as best you can. For example, if you have too much to do in too little time, set realistic goals and establish priorities.

Let the least important items go for now. If, on the other hand, you feel stressed by a lack of focus or challenge in your life, look for new activities and interests to help you get out of a rut. Whatever the cause of your stress, find constructive ways to reduce or eliminate it. Don’t rely on alcohol, nicotine, or drugs to solve problems.

• Autoregulation techniques. Experiment with deep breathing, progressive muscular relaxation, or meditation. By learning to relax your body, you may find that you can relax your mind.

• Mindfulness. You can also incorporate mindfulness, the practice of being aware of your thoughts and feelings, in everyday life. Try the following:

1. Make something that occurs several times a day, such as answering the phone or buckling your seat belt, a reminder to return to the present—that is, think about what you’re doing and observe yourself doing it.
2. Pay attention to your breathing or your environment when you stop at red lights.
3. Before you go to sleep and when you awaken, take some “mindful” breaths. Instead of allowing your mind to wander over the day’s concerns, direct your attention to your breathing. Feel its effects on your nostrils, lungs, and abdomen. Try to think of nothing else.
4. If the present moment involves stress—perhaps you’re about to speak in public or undergo a medical test— observe your thoughts and emotions and how they affect your body.
5. Find a task you usually do impatiently or unconsciously (standing in line or brushing your teeth, for example), and really pay attention to what’s going on.

• Counseling or psychotherapy. Seek help from a mental health professional, such as a psychologist, social worker, or psychiatrist. Support groups and stress-management classes can also help.

• Anger management. At least two studies have shown that people with heart disease can curb their anger by getting regular exercise or counseling. The studies also found that reducing anger and hostility levels could decrease participants’ risk factors for heart disease and make them feel better, as well as forestall the recurrence of heart attacks. It’s not known whether anger management can prevent heart disease.