“You're probably familiar with the insidious effects of stress on your sleep quality and its link to anxiety and depression. Now growing body of evidence suggests that stress can take a physical toll, too, damaging everything from your heart to your immune system. It may even shorten your lifespan. "Chronic emotional stress can affect virtually every organ system in negative ways," says Dean Ornish, M.D., founder and president of the Preventive Medicine Research Institute in Sausalito, Calif. "But stress is not simply a function of what you do. It's also a function of how you react."
Cortisol seems to "tune down" the immune system and make it less able to fight infection, says Esther Sternberg, M.D., director of the integrative neural immune program at the National Institute of Mental Health. Various studies by Ohio State University (OSU) scientists have found that dementia caregivers have poorer immune function and suffer more sick days, especially respiratory illnesses, than other people. Even immunizations don't offer them as much protection as they do noncaregivers: Caregivers of Alzheimer's and dementia patients make fewer antibodies (disease-fighting proteins) when they're vaccinated against the flu, making them more susceptible to catching the virus, the OSU researchers and scientists at the University of Bristol in England found. In the case of cancer, epinephrine and norepinephrine can cause tumors to spread by increasing their ability to promote the growth of blood vessels that increase the cancer's supply of blood and nutrients, according to 2006 research on lab mice at the University of Texas M.D. Anderson Cancer Center in Houston.
And when we comment that a president's hair seems to have gone white overnight, it turns out that stress really may be aging him. OSU researchers have found that genetic material that's responsible for helping to repair cells is biologically "older" in caregivers than it is in other people. While there's no proof that this genetic aging shortens one's lifespan, that cell aging is associated with many cancers, heart disease and the body's disease-fighting abilities, Ornish says. (Separate research has, however, found that caregivers who are emotionally stressed out have higher rates of mortality than other people.) Stress can also have a physical effect on our health if it leads us to behave in unhealthy ways, such as over eating or drinking too much alcohol, a 2007 commentary in the "Journal of the American Medical Association" noted.
Stress doesn't affect us equally. "The greater the stress, the more prolonged, the more severe, the more likely you are to become ill," Sternberg says. And while some studies suggest that women report more stress and symptoms of it, they may also manage it better, suggesting that how we cope with stress can influence whether it makes us sick.
Research at Carnegie Mellon University has shown that people with strong social networks tend to be healthier. There may also be a gender difference: females of many species, including humans, are apt to "tend and befriend" in times of stress by taking care of children and other adults, according to UCLA psychologist Shelley Taylor, Ph.D. That trend was borne out in Hungary after the fall of the Soviet Union: Both men and women there were affected by unemployment at that time, but despite the economic changes, women's social networks in their towns and churches remained the same. Men, however, suffered more heart disease and death, possibly because they were more psychically affected by economic stresses, according to a 2004 study published in "Brain Research Bulletin."
In addition to having friends to lean on, listening to music, exercising and practicing yoga and meditation all have been shown to reduce stress. And there's reason to believe those strategies can make a difference to your health. Ongoing research by Ornish suggests that stress - management techniques such as exercise, yoga, meditation and support from others - along with a low-fat diet - are associated with lowered LDL or "bad" cholesterol, as well as a "turning off" of genes that promote cancer growth. Those activities also were associated with increased production of telomerase, a protein that repairs the genetic material that controls aging. "You can't get rid of stress, you can't get rid of negative events in your life, but you can do things to cushion yourself from them," Sternberg says. And that, Ornish says, is "a very empowering and optimistic message."