Let Us Pray

Back in the '80s, Harold Koenig, M.D., a psychiatrist who specialized in geriatric medicine, began asking his patients, "How do you cope with stress?" Many said they relied on their religious faith. This powerful idea had not been addressed in much of the scientific literature, so Dr. Koenig decided to study it. His research started an academic trend, and Dr. Koenig is now the codirector of the Center for Spirituality, Theology and Health at Duke University Medical Center -- a juxtaposition of science and theology that would have been hard to imagine three decades ago.

In the 1990s Dr. Koenig's research found a link between higher rates of faith and lower rates of depression. In later studies he found that people who pray daily and attend services weekly tend to have lower blood pressure. On top of that, people who attend religious services are almost 50 percent less likely to have high interleuken-6 levels (which indicate poor immune system function) than are people who don't attend services. In plain English, the more religious you are, the less stressed out you tend to be. Which often means you're healthier.

Since Dr. Koenig started his work, lots of other researchers have jumped on the bandwagon. He estimates that, to date, at least 3,000 studies have looked at whether religious faith affects physical or mental health. Between half and two-thirds of the studies do find a link. And the doctors who are out on the front lines seem to agree: According to a 2007 survey published in the Archives of Internal Medicine, 54 percent of doctors said "a supernatural being" (aka God) sometimes affects a patient's health.

Daniel Sulmasy, M.D., a Franciscan friar and the Kilbride-Clinton Professor of Medicine and Ethics at the University of Chicago, cautions that it's theologically wrongheaded to pray just to reap the health benefits. "God is not Prozac," he says. Still, he's not surprised at the positive research results. Dr. Koenig's blood-pressure findings ring especially true for him. "I can almost sense it in myself, the relaxation that is part of a deep meditative experience," says Dr. Sulmasy.