•  Illness: The Mind-Body Connection •  Mind-Body Connection •  Stress

They say that stress is a killer. But most of us don't interpret that literally. We know that stress is bad for our health, but few of us are aware of the role it can play in producing such real killers as heart attacks and strokes.

"A critical shift in medicine has been the recognition that many of the damaging diseases of slow accumulation can either be caused or made far worse by stress," writes Robert M. Sapolsky, author of the critically acclaimed Why Zebras Don't Get Ulcers. "Stress can wreak havoc with your metabolism, raise your blood pressure, burst your white blood cells, make you flatulent, ruin your sex life, and if that's not enough, possibly damage your brain."

What's important to remember, writes Sapolsky, a professor of biological science and neuroscience at Stanford University, is that effectively managing your stress can be a powerful weapon against serious illness.

Stress is our reaction to any situation that frightens or worries us. In response to a threatening trigger, our bodies produce adrenaline, a hormone that speeds up heart rates, produces rapid breathing, and increases alertness and vigilance.

Short-term bursts of stress are not necessarily bad; in fact, they can trigger chemicals that can improve your memory, increase your energy, and cause you to become more alert and productive. If you're a zebra, and a hungry lion is chasing you across the savanna, the resulting adrenaline makes you run faster, think quicker, and swiftly remember how you saved your skin the last time.

However, zebras, and most other mammals for that matter, don't suffer chronic stress the way humans do. Once the zebra escapes from the lion, his stress is over (until the next predator comes along). Zebras don't have mortgages, traffic jams, or unpaid overtime. They don't worry about paying the bills, getting sick, or being accepted into a good college. Experts say it's chronic stress that is such a threat to human health.

Chronic stress -- living under stressful conditions for long periods of time -- can have a profoundly negative impact on your body. When we experience a threat, whether it's physical or psychological, our bodies go into overdrive. Activity in the sympathetic nervous system rises and the adrenal glands release the hormones epinephrine (or adrenaline) and norepinephrine into the bloodstream. At the same time, the adrenal glands also release cortisol, a hormone that sends the body the message to release fatty acids for a burst of energy.

This nervous system and hormonal activity cause digestion to slow down, blood sugar levels to rise, and the heart to pump more blood to the muscles. This is useful when a car is swerving toward you, but damaging when these hormones are in overdrive too often. Not only does chronic stress contribute to stomach problems, constipation, diarrhea, and more frequent colds and respiratory infections, it can also undermine long-term health.

It's now known that high levels of cortisol "take a toll on our bodies and can worsen inflammatory conditions such as colitis and eczema, as well as autoimmune disorders like rheumatoid arthritis, lupus, and multiple sclerosis," says David Katz, MD, director of the Yale Prevention Research Center in New Haven, Connecticut.

There's increasing evidence that stress is a contributing factor to conditions such as high blood pressure, heart disease, and diabetes.

As Sapolsky explains it, "If you constantly mobilize energy at the cost of energy storage, you will never store any surplus energy. You will fatigue more rapidly, and your risk of developing a form of diabetes will even increase. The consequences of chronically overactivating your cardiovascular system are similarly damaging: If your blood pressure rises to 180/140 when you are sprinting away from a lion, you are being adaptive, but if it's 180/140 every time you see the mess in your teenager's bedroom, you could be heading for cardiovascular disease."

High blood pressure causes the heart to work harder than normal, and increases the risk for heart attacks, strokes, and kidney failure. According to one recent study, mental stress causes the inner layer of the blood vessels to constrict, which may increase the risk of sudden cardiac death. The research, published in Circulation found that sudden mental stress induces "endothelial dysfunction," doctorspeak for a condition in which the blood vessels' ability to dilate is impaired. As a result, the blood vessels are unable to expand and contract to accommodate different amounts of blood flow. The condition can increase the risk of a heart attack or stroke.

In fact, in September 2004, Canadian researchers published a landmark study of nearly 25,000 people from 52 countries that identified the major causes of heart disease. The study found that lingering stress more than doubled the risk of heart attacks, nearly putting it on a par with smoking.

Another study found that people with existing heart disease face greater risks of serious cardiac events during emotional stress. For example, researchers found that in the 60 days after the September 11, 2001 attacks, New York Methodist Hospital in Brooklyn treated 35 percent more heart attacks and 40 percent more tachyarrhythmias (irregular heartbeats) than in the 60 days before the attacks. Heart attacks and cardiac arrhythmias are both related to a surge in stress hormones known as catecholamines, which stimulate nerve chemicals, said Jianwei Feng, MD, lead author of the study, who is now a cardiology fellow at the University of Texas Health Science Center in Houston.

Researchers now believe stress can contribute to diabetes. In people with type 2 diabetes, stress hormones can raise the level of glucose in the blood while physical stress, such as illness or injury, causes higher blood glucose levels in people with either type 1 or type 2 diabetes.

In recent years organizations such as the American Diabetes Association, the American Heart Association, and American Cancer Association have begun to focus on the link between stress and the conditions they are striving to cure.

In the same way that some people worry more than others, stress causes a stronger physical reaction for some of us than it does for others. And those whose bodies are more easily aroused by stress when they're young can suffer greater long-term damage when they're older. In one recent study, young adults who reacted to psychological stress with spikes in blood pressure were more likely to have high blood pressure when they reached their 40s.

"In general, the individuals who had larger blood pressure responses to stress, had a greater risk for developing high blood pressure," said lead researcher Karen A. Matthews, a professor of psychiatry at the University of Pittsburgh. This risk was independent of other known risk factors such as race, gender, education, age, and body-mass index (BMI), she added.

Another study found a direct link between anxiety, stress, and unhealthy reactions. According to recent research by Christine M. Albert, professor at the Harvard University School of Public Health in Boston, high levels of psychic stress, specifically phobic anxiety, increase the risk of sudden cardiac death in women. Albert studied women enrolled in the national Nurses Health Study and found that those with high anxiety were at an increased risk of sudden cardiac death.

The best strategies for dealing with stress involve making lifestyle changes to allow more time for rest and relaxation. Getting at least a moderate amount of exercise each day helps to ease tension and also leads to deeper, more restful sleep. A healthy diet and enough sleep every night are useful in controlling your stress levels as well.

Relaxation techniques can also help. Try breathing exercises, such as inhaling a deep breath and holding it for as long as you can before letting it out, or progressive relaxation therapy, which involves tensing then relaxing your muscles bit by bit, starting with your toes and going all the way up to the top of your head. Meditation is a great stress-fighting technique, as is yoga or doing stretching exercises. Do some experimenting to find out what method of relaxation works best for you. In the long run, it might just save your life.

-- Melanie Haiken is a freelance writer based in San Rafael, California who has worked as the health editor of Parenting magazine and the executive editor of San Francisco magazine and BabyCenter.com. Elaine Herscher is the special projects editor for Consumer Health Interactive.

References

First published September 22, 2004
Last updated February 20, 2008
Copyright © 2004 Consumer Health Interactive

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