Stress and heart disease

For years it has been “common knowledge” that people who are under a lot of stress have an increased risk of heart disease. But is this common knowledge correct? And if so, what kind of stress increases the risk of heart disease, how does it increase risk, and what can be done about it?

Sorting out the effect of stress on the heart is made complicated by three factors: 1) people mean different things by “stress;” 2) the kind of stress people think causes heart disease may not be the worst kind; 3) until recently, there has been little scientific evidence that stress causes heart disease.


What kind of stress are we talking about?
When people refer to “stress,” they may be talking about two different things: physical stress, or emotional stress. Most of the medical literature on stress and heart disease refers to physical stress. But most people are referring to the emotional variety when they talk about stress.

Physical stress: Physical stress – exercise or other forms of physical exertion – places measurable and reproducible demands on the heart. This physical stress is generally acknowledged to be good. In fact, the lack of physical stress (i.e., a sedentary lifestyle) constitutes a major risk factor for coronary artery disease. So this kind of “stress” is usually considered to be good for the heart – as long as the heart is normal.

If there is underlying heart disease, however, too much physical stress can be dangerous. In a person who has coronary artery disease, for instance, exercise can place demands on the heart muscle that the diseased coronary arteries cannot meet, and the heart becomes ischemic (i.e., starved for oxygen.) The ischemic heart muscle can cause either angina (chest pain), or a heart attack (actual death of cardiac muscle).

In summary, physical stress is generally good for you, and is to be encouraged, as long as you have a normal heart. On the other hand, with certain kinds of heart disease, too much or the wrong kind of physical exertion may be harmful.
But either way, physical stress does not cause heart disease.

Emotional stress: Emotional stress is generally the kind of stress people are talking about when they refer to stress causing heart disease. “It’s no wonder she died,” you’ll hear people say, “with all the mess he put her through.” But is it true? Did Ed really kill Elsie with all his gambling and drinking and staying out all hours of the night?

Everyone – even doctors – have the notion that emotional stress, if it is severe enough or chronic enough, is bad for you. Most even believe that this kind of stress can cause heart disease. But scientific evidence that it actually does so has been hard to come by.


Emotional stress and heart disease
There is a fair amount of circumstantial evidence that chronic emotional stress can be associated with heart disease and early death.

Several studies have documented that people without spouses die earlier than married people. (While some might claim this constitutes evidence that emotional stress is actually good for you, most authorities agree that having a spouse actually provides a significant degree of emotional support and stability.) Other studies have shown fairly conclusively that people who have had recent major life changes (loss of a spouse or other close relative, loss of a job, moving to a new location) have a higher incidence of death. People who are quick to anger or who display frequent hostility have an increased risk of heart disease.

So emotional stress is bad, right? It didn’t start out bad. Evolutionarily speaking, emotional stress is a protective mechanism. When our ancestors walked over a rise and suddenly saw a saber-tooth tiger 40 yards away, a surge of adrenaline prepared them for either fight or flight as they considered their options.

But in modern times, now that saber-tooth tigers are few and far between, most often neither fight nor flight is the appropriate reaction to a stressful situation. (Neither fleeing from nor punching your annoying boss, for instance, is generally considered proper.) So today, the adrenaline surge that accompanies a stressful situation is not channeled to its rightful conclusion. Instead of being released in a burst of physical exertion, it is internalized into a clenched-teeth smile and a “Sure, Mr. Smithers, I’ll be happy to fly to Toledo tomorrow and see about the Henderson account.”

It appears that the unrequited fight-or-flight reaction, if it occurs often enough and chronically enough, may be harmful.


How does emotional stress cause heart problems?
From a scientific standpoint, we really don't know for sure that it does. But we do know that people who live in a chronically stressed-out condition are more likely to take up smoking and overeating, and are far less likely to exercise.

We also know that the surge in adrenaline caused by severe emotional stress causes the blood to clot more readily, increasing the risk of heart attacks. British investigators have shown that chronic work stress can produce chronic increases in adrenaline levels, and have related those changes to an increased risk of heart disease. A study at Duke University showed that the stress of performing difficult arithmetic problems can constrict the coronary arteries in such a way that blood flow to the heart muscle is reduced.

So science is beginning to support the theory that chronic emotional stress can promote coronary artery disease. Certainly such stress is associated with behaviors that increase coronary artery disease, and there's at least suggestive evidence that it may even have a direct effect in producing coronary disease.


Is all emotional stress bad?
No. It has been observed for years, for instance, that many executives with high-pressure jobs seem to remain quite healthy until old age – they seem to flourish in their pressure-cooker jobs. Recent studies have shed light on this phenomenon.
It turns out that the type of emotional stress one experiences is important. In comparing the outcomes of individuals with different types of job-related stress, it was found that people with relatively little control over their own workplace destiny (clerks and secretaries for instance) fared far worse than their bosses. (Bosses, of course, tend to have more control over their own lives – and the lives of others. As someone once said, it’s good to be king.) A sense of loss of control, therefore, appears to be a particularly important form of emotional stress. Furthermore, this evidence seems to confirm that if some sense of control over one’s destiny is maintained, job related stress can be exhilarating rather than debilitating.


What can be done about emotional stress?
Actually, quite a bit of evidence suggests that it may be the individual, and not the stress itself that is the problem. People with Type A personalities (time-sensitive, impatient, chronic sense of urgency, tendency toward hostility, competitive) are at higher risk for coronary artery disease than people with Type B personalities (patient, low-key, non-competitive). In other words, given the same stressful situation, some will respond with frustration and anger, the rush of adrenaline and the fight-or-flight mode, and some will react serenely.

This is why the common advice to “avoid stress” is so useless. Nobody can avoid all stress without completely dropping out of society and becoming a monk. Besides, people of the Type A persuasion will create their own stressful situations. A simple trip to the grocery store will be filled with episodes of bad drivers, poorly-timed traffic lights, crowded aisles, indifferent checkout clerks, and thin plastic grocery bags that rip too easily. “The world is filled with half-brained incompetents whose only purpose is to get in my way,” they will conclude. “It’s a wonder any of them survived to adulthood.”

With this sort of mind-set, retiring, changing jobs, or moving to Tucson are not likely to significantly reduce stress levels – the stress will be there whether it is imposed externally, or whether you have to manufacture it. Reducing stress levels in these cases, then, requires not an elimination of stressful situations (which is impossible), but a change in the way stress is handled. Type A’s have to learn to become more B-like.

Essentially, new responses need to be learned, so that the fight-or-flight adrenaline surge is not automatically engaged at the first sign of trouble. Stress management programs have begun to demonstrate some success in accomplishing this end.

Stress management programs often consist of breathing exercises, stretching exercises, Yoga, meditation, and/or massage. There are probably several useful approaches, but they all aim toward the same goal – to blunt the adrenaline response to minor stress.

A recent study from Duke University reported a significant reduction in heart attacks among patients with coronary artery disease who underwent a formal stress management program, which was used in conjunction with a smoking cessation program, a weight-loss program, and control of lipids.


Recommendations
Stress management techniques may be quite helpful in reducing the risk of coronary events, and have the added benefit of being risk-free. Thus, there seems to be little reason not to recommend some form of stress management in people with heart disease, or with risk factors for heart disease. And finally, it should be pointed out that exercise is a great way of reducing chronic stress, and in addition has the advantage of directly lessening the risk of coronary artery disease, and helping to control obesity.

By Richard N. Fogoros, M.D., About.com