Diabetes Forecast

Stressing Less

Dealing with stress the right way may safeguard your health

By Erika Gebel, PhD , ,

The clock is ticking and the traffic is horrendous. Late to work again. And you left your blood glucose meter at home. Hello, stress. We've all felt, at one time or another, the stomach-clenching grip of stress. Scientists are discovering that it's a serious health hazard. Type 2 diabetes, for example, may be brought on in part by stress. Constant anxiety may be detrimental for people with diabetes, too, but don't let that worry you; there are strategies for tackling stress.

Prehistoric Relic

Acute stress, or stress related to a specific sudden situation or event, is the body's general response to a challenge. When the body experiences acute stress, adrenaline and other stress hormones spike. This stimulates the nervous system to coordinate a series of physical changes that prime the body for "fight or flight." The pulse quickens, digestion slows, and the body liberates nutrients, including fat and glucose, to provide quick energy. In prehistoric times, this stress response provided our ancestors with the energy boost they needed to deal with large predators.

Nowadays, humans seldom need to flee from massive beasts. Yet, we still experience acute stress in response to modern stimuli. "We are experiencing that same response, day in and day out," says Nancy Adler, PhD, professor of psychiatry at the University of California–San Francisco, "like if your boss yells at you."

The question is: What does the stress response do to a modern human's health? To answer that, researchers trigger stress in the laboratory and measure the physical changes that result. "The best thing to induce stress is public speaking," says Adler. After making volunteers speak in front of audiences, researchers measure hormone levels in participants' saliva. They've found that acute stress increases levels of cortisol, a hormone that raises blood glucose levels —a "code orange" danger alert of sorts.

Daily Stress

For most people, an occasional stress response isn't thought to be harmful (except for those with certain conditions, such as heart disease). The harm comes when stress becomes an everyday experience, repeatedly raising cortisol and blood glucose levels and altering other aspects of physiology. "If this becomes a chronic experience, over time it has this wear and tear on the body," says Adler.

After a bout of acute stress, the body is supposed to dial down the hormones and calm the nerves, returning to business as usual. However, evidence suggests that if the body experiences stress frequently, it never gets back down to a calm state of code green. The body may get stuck at code orange, a heightened state of readiness. Essentially, the body ends with perennial low-level stress, in which levels of stress hormones such as cortisol are elevated and the body systems remain more geared up than is normal or healthy. This is what doctors and scientists refer to as chronic stress.

Chronic low-level stress affects the brain, heart, lungs, and muscles, and has been linked to a variety of health conditions, including poor immune system function, heart disease, cancer, type 2 diabetes, and gastrointestinal problems. Even so, scientists are still trying to figure out the exact biological changes caused by stress that lead to disease. Stress may also affect health by modifying behavior, such as spurring people to seek out sweet and fatty comfort foods. "If you stress rats and give them a choice of foods, they'll go for the junk-food equivalents," says Adler. "This brings down cortisol levels. It's a short-term fix with a long-term cost."

Stress and Diabetes

Stress-related biological changes, such as a spike in cortisol, can temporarily raise blood glucose to out-of-range levels in people with type 1 or type 2 diabetes. Less clear, however, is whether psychological stress itself can cause people to develop consistently high blood glucose levels and a diagnosis of diabetes. There is growing evidence that chronic stress does lead to type 2 diabetes, although how it does so isn't fully worked out.

One piece of evidence linking stress and type 2 is that people tend to develop diabetes after tragic life experiences. A 2000 study published in Diabetes Care found that people who'd had a significant life stress, such as the death of a loved one, in the previous five years were 1.6 times as likely to develop type 2 diabetes as those who'd been living relatively free of stress. The increased risk was not related to body weight, suggesting that stress-related biological factors and not weight gain were to blame. A 2004 study in Psychological Medicine showed that a history of childhood neglect doubled the risk for developing type 2 diabetes in adulthood. Another study that year in Occupational Medicine found no evidence, however, that stressful life events cause type 1 diabetes.

A major source of stress in people's daily lives is work, and researchers have looked to see if job stress raises the risk for type 2. A 2009 study in Diabetes Care found that women with job strain caused by too many demands and too little social interaction had twice the risk of developing diabetes over 15 years than those with few work woes. The association held up even after accounting for weight gain and physical inactivity. The diabetes link wasn't observed in men, perhaps because few men in the study were in the low-level positions that tend to be more stressful.

Another way stress may increase the risk for type 2 diabetes is by disrupting sleep. A 2010 study in Diabetes Care found that people with sleep problems—difficulty falling or staying asleep, sleeping fewer than five to six hours a night or more than eight to nine hours—are 30 percent more likely to develop type 2 than sound sleepers. "That fascinates me," says Frans Pouwer, PhD, professor of psychosomatic research in diabetes at Tilburg University in the Netherlands. "What we need right now is intervention studies. We have risk factors, but we don't know if we can reduce the risk of diabetes" by, for example, helping people get the right amount of sleep.

Oxidative Stress

There is evidence that emotional stress can lead to a certain type of "stress" on body tissues, sometimes referred to as oxidative stress. Oxidative stress occurs when cells are damaged by reactive oxygen, a by-product of normal chemical reactions in the body. Reactive oxygen is usually removed quickly by protective chemicals known as antioxidants, but when this system breaks down, oxidative stress can result. Emotional stress may somehow lead to higher amounts of reactive oxygen, which in turn may lead to abnormally high levels of oxidative stress and damage to body tissues.

Dial It Down

One person's stress is another person's surmountable challenge. The effect stress has on health may have to do with how a stressor is perceived, says Adler. She breaks a stressful situation into three parts: the stressor or external threat, the stress appraisal, and the biological stress response. The stress appraisal—how a threat is perceived in the mind—determines how the body responds, Adler says. For example, a car breaking down would be less stressful to a person who can afford repairs easily than to someone who is struggling financially.

Evidence that perception is key comes from a 2004 study in the Proceedings of the National Academy of Sciences that compared women with healthy children to those raising a child with a chronic illness. The researchers measured the length of the mothers' telomeres—the ends of chromosomes that protect genes in the center of a chromosome from damage. Telomeres shorten as people age, and some scientists think age-related diseases are associated with telomere shortening. The researchers found that both groups of mothers had, on average, telomeres of the same length. However, mothers who reported perceiving higher levels of stress had shorter telomeres than those who didn't feel as stressed, regardless of the health of their child. This study suggests that telomeres may be a biological link between stress and health.

Studies consistently show that people with less money and education are at increased risk of developing type 2 diabetes and that stress may be a factor in that relationship. Adler compared the health of people with type 2 diabetes. They were enrolled in the same health care system and got the same quality of care, but they had different levels of education. People with less schooling had more complications, such as heart disease, strokes, and kidney disease, than those with more education. "We are still analyzing the data," Adler says, but she suspects that "what education gets you is more knowledge, which may help you to avoid certain stressors. You've learned how to organize your life so you encounter fewer chaotic threats."

Lessen the Stress

So how can people learn to reframe their perception of stress to make it manageable, without going to graduate school? "One of the ways to buffer stress is exercise," says Adler. "Interventions that increase exercise have been effective." A recent example, published this September in Medicine & Science in Sports & Exercise, found that participants who'd cycled for 30 minutes felt calmer after looking at stress-inducing images than those who had rested for 30 minutes. "I often say to patients it's not necessary to become a top [athlete]" to stress less, says Pouwer. "Taking a bike to get stuff from the shops is activity, too."

An approach to boosting mental resilience that's gaining traction is mindfulness ("Stress Reducers," above left). "View your thoughts as a train," says Pouwer. "You can either jump on the train or you can watch the train." Mindfulness is watching the train and may give practitioners greater control over their response to stress. In a study published this year in Diabetes Care, people with diabetes who took a course in mindfulness reported having less emotional distress and a better quality of life. "They learned how to cope with stress," says Pouwer, a researcher on the study. Another small 2007 study in Alternative Therapies in Health and Medicine reported that mindfulness training improved blood glucose control in people with diabetes. Research into the benefits of mindfulness in people with diabetes is still in its infancy, says Pouwer, but he calls the results so far "promising."

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