How Stress Makes You Sick
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How Stress Makes You Sick

Stress can damage almost every part of your body.

Stressed-Out Mom

It's 1 a.m. and Michele JuVette, 42, a daycare provider in Mansfield, Texas, and the mother of four boys -- "five if you count my husband," she jokes -- is ready to call it a day. She's been going nonstop since 6 a.m., getting the boys, ages 6, 9, 14, and 16, off to school, juggling calls for her home-based business, tending to the three infants in her care, scheduling upcoming extracurricular activities, picking the boys up from school, making dinner and cleaning up afterward, helping the children with homework, and passing her husband, Scott, 42, photo director of a video-production company, as he comes in the door and she goes out to do grocery shopping and other errands.She's dead tired when she finally crawls into bed, but as her head sinks into the pillow, her mind starts to race with all of the things she needs to accomplish tomorrow. She's lucky to get four or five hours of shut-eye -- not nearly enough to start it all over again the next day. "We are at maximum overdrive on a constant basis," she says of her family. All this craziness is taking a toll on her health. A normally upbeat person, JuVette feels depressed and rundown. And she has another, surprising symptom: One day after a shower she noticed an unusually large amount of hair in the drain. Then she found wads of hair in the vacuum cleaner. "My hair was falling out in handfuls," she says. Her family doctor ruled out illnesses such as thyroid disease and concluded her hair loss was a symptom of stress. "I was shocked to learn what my stress was doing to my health," she says.


What Stress Can Do

Like JuVette, most of us don't know that stress can affect so many different parts of our bodies, from our muscles and tissues to our blood vessels and organs. It speeds up heart rate and respiration, raises blood pressure and body temperature, and can interfere with metabolism, appetite, digestion, sexuality, fertility, and sleep. It can shut down a woman's menstrual cycle, perhaps triggering early menopause, and can decrease a man's production of testosterone, impairing his fertility. New research suggests that high levels of stress during pregnancy can actually make a woman's children more sensitive to stress. Stress weakens our immune system, can exacerbate depression, and impairs our memory by shrinking a crucial part of our brain, perhaps permanently. It can make us fat and, if allowed to progress unchecked, stress can contribute to such life-threatening conditions as multiple sclerosis, lupus, rheumatoid arthritis, osteoporosis, cancer, diabetes, and heart disease.The science supporting these conclusions is now unequivocal. "We know stress can kill," says Esther Sternberg, MD, chief of the section on neuroendocrine immunology and behavior at the National Institute of Mental Health, in Bethesda, Maryland. "If the body doesn't have a chance to recuperate, the effects of stress compound, with a longer-lasting and more harmful effect on our health." In fact, chronic stress, defined as ongoing worries that continue over several months or longer, may shorten life expectancy by 15 to 20 years, according to researchers at the National Institutes of Health.

When Stress Is Good

The stress response originates in our heads or, more precisely, in the hypothalamus, a section of the brain that regulates blood pressure, body temperature, respiration, sleep-wake cycles, hunger, and sexual function. The hypothalamus has another job: to survey our surroundings for danger and prepare us to fight or flee. It does this by sending out a warning to the adrenal glands, which in turn flood the bloodstream with adrenaline. This hormone increases our heart rates and sends blood to our muscles and extra oxygen to our brains to keep us alert. At the same time, our brains secrete natural painkillers, known as endorphins, to help us withstand injuries we may incur. The hypothalamus also sends a substance to the pituitary gland in the brain, which triggers the adrenal glands to make the stress hormone cortisol, which releases glucose and fatty acids for extra energy. This whole process may take only a few seconds.Under life-or-death conditions, all this is beneficial, as when, for example, a mother needs to rush into the street to scoop her child from the path of an oncoming car. But can stress be good on a more regular basis, too? Absolutely, says Dr. Sternberg, author of The Balance Within: The Science Connecting Health and Emotions (W.H. Freeman & Co., 2001). We need those extra jolts of adrenaline to achieve peak performance in our daily lives. Unlike animals, however, humans also face psychological stressors. Whether they are imminent (such as difficulty paying the rent or mortgage) or longer-term (a child not doing well in school), the stress hormones rush to our aid. If our internal feedback system is working properly, when the threat or our stressful thoughts about it have passed, our adrenals send a message back to the hypothalamus telling it to stop producing excess cortisol and adrenaline.Many of us, however, are so overwhelmed by stress that the circuit doesn't stop. Too much of a good thing turns bad, and these chemicals act like a poison, which can then negatively affect our health.

Stress and Fat

Stress may depress the appetite -- at first. But as cortisol levels rise, so does our desire for food. We don't tend to reach for something nutritious, though, such as carrot or celery sticks. We're more apt to crave sugary, carbohydrate-rich, and fatty foods. "It's very clear from experiments with animals that eating starches and sweets blunts the stress response," says Louis Aronne, MD, clinical associate professor of medicine and director of the Comprehensive Weight Control Program at New York-Presbyterian Hospital, in New York City.Cortisol is the key player, triggering the body to seek high-energy foods. Once we've stuffed ourselves, the fat cells send signals back to the brain telling it that we've refueled and the brain stops producing stress hormones, which relaxes us -- temporarily. If we're under chronic stress, as soon as we burn the fat deposits off, our cortisol level spikes and stimulates our appetite again. "It's a vicious circle," says Dr. Aronne. "You're under chronic stress and your body starts producing hormones that increase the pleasure of eating sugar, starch, and fat. But the more you eat, the hungrier you get."Because cortisol remains elevated for hours after the stress has subsided, "our appetites stay ramped up for a very long time," notes Shawn Talbott, PhD, director of the nutrition clinic at the University of Utah, in Salt Lake City, and author of The Cortisol Connection (Hunter House, 2002). As a result, he says, "We eat when we're not really hungry -- and we get fat." Stress may also trigger a disorder known as the night-eating syndrome, in which people eat one-third or more of their daily calories after their evening meal, sometimes getting up once or twice during the night to snack. In fact, scientists think this syndrome may be an unrecognized stress-related contributor to the obesity epidemic in this country.

Heart-Stopping Risk

Stress doesn't just make us fat, it influences where that fat goes, and that has a bearing on our heart health. Before menopause, when production of estrogen and progesterone is high, women tend to gain weight at the hips, producing the so-called pear shape, while men put on pounds around the abdomen, the apple shape that is associated with heart disease. In women, however, chronic stress can cause excess fat to build up around the abdomen, placing us at greater -- and earlier -- risk for cardiovascular disease.The link between stress and cardiovascular disease is well established, but scientists are still working to pin down more of the complex ways that stress damages the heart. One theory is that the stress hormone adrenaline increases the heart rate, which in turn causes a rise in blood pressure that sends more oxygen to the large muscles of the arms and legs. Repeated surges can cause blood pressure to stay elevated, the condition we know as hypertension, potentially damaging the blood vessels in the coronary arteries and triggering a heart attack in otherwise healthy people, says Bruce S. McEwen, PhD, head of the neuroendocrinology laboratory at Rockefeller University in New York City and coauthor of The End of Stress as We Know It (Joseph Henry, 2002). In fact, a sudden severe stress, such as the death of a loved one, can cause the inner layer of the blood vessels to constrict, increasing the risk of sudden cardiac death. Stress also ratchets up the risk of death in people who already have heart disease. For women, stress may also lower estrogen levels in the blood and increase the risk of heart disease before the onset of menopause, a time when most women have natural heart protection. If severe enough, stress can actually reduce estrogen so much that women stop menstruating. But even moderate drops in estrogen that don't cause symptoms can have adverse effects on the heart.

Colds, Flu & Disease

We've all had the experience of catching a cold or the flu when we're under a huge amount of stress. There's a physiological reason for this, and cortisol plays a starring role. Normally, our white blood cells, or immune cells, fight off intruders such as bacteria and viruses. But extreme stress can overwhelm the troops, so the immune system relays a message to the hypothalamus in the brain, calling for reinforcements. The hypothalamus responds by raising our temperature to make the body inhospitable to intruders. It also engages the pituitary and adrenals to produce cortisol, which sends more white blood cells to sentry posts throughout the body. Then, something unfortunate can happen. "As stress hormones and chemicals pour out, immune cells never get a chance to recover from the unabated rush of cortisol," says Dr. Sternberg. Overwhelmed by the warrior hormone, the immune cells are less able to react to pathogens. In a strange twist of biology, the same hormones that help us fight infection can also switch off the immune system, making us more vulnerable to contagious bugs. Occasional, short-lived stress usually isn't a problem, but when stress becomes chronic, the immune system can become impaired in a major way. Husband and wife team Janice Kiecolt-Glaser, PhD, and Ron Glaser, PhD, of Ohio State University College of Medicine, in Columbus, have been studying the connection between chronic stress and health for decades, and note numerous links between our modern-day pressures and immunity. In a 2002 paper published in the Journal of Consulting and Clinical Psychology, they write that chronic stress delayed wound healing from 24 to 40 percent among subjects. "We were surprised by how large the effects were," says Dr. Kiecolt-Glaser. A subsequent study determined the mechanism: People under chronic stress produced significantly lower levels of cytokines, substances that are crucial for wound repair.They also discovered that people who are perpetually stressed do not respond as well to vaccines. In a study of women and men caring for a spouse with Alzheimer's or another dementia, they found that only 38 percent of the caregivers produced significant antibodies to a flu vaccine, versus 66 percent for the control group. "This type of caregiving is an uncontrollable, unpredictable stressor, and among the very worst types," explains Dr. Kiecolt-Glaser. "It takes away your major source of support -- your spouse -- and replaces it with a major stress instead."Chronic exposure to multiple stressors can lead to burnout, making us incapable of responding to stress with even a slight burst of cortisol. Under such conditions, the immune system starts to attack itself and may make us more susceptible to inflammatory and autoimmune disorders, such as rheumatoid arthritis, fibromyalgia, and lupus.


Originally published in Ladies' Home Journal magazine, April 2004.