Type 2 diabetes. Working up a sweat not only helps keep blood glucose under control, but also addresses heart and blood flow problems, reducing the risk of heart disease and nerve damage—common concerns for people with diabetes. For a study ending in 2001, the National Institutes of Health enrolled roughly 3,200 people at risk for diabetes in a two-year program. One group was asked to make lifestyle changes, including losing 7 percent of their body weight through diet and exercising at least 150 minutes weekly. A second took the diabetes drug metformin, and the third was the placebo or control group. After roughly three years, the lifestyle-changers showed a 58 percent reduced incidence of diabetes and the metformin patients a 31 percent reduction when compared to the rate of diabetes in the placebo group. A 10-year follow-up study for NIH's Diabetes Prevention Program confirmed these results. The lifestyle patients who had relied on exercise and diet showed a 34 percent reduction in diabetes incidence versus 18 percent in the metformin group when compared to the diabetes rate in the placebo group.
Heart disease. Exercise has long been known for its healthful effects on the cardiovascular system. A study from Brigham and Women's Hospital in Boston, published in 2007, showed that the benefits rise with the amount of physical activity. Researchers reviewed records of more than 27,000 women who had been followed for an average of 10 years. They found that those who engaged in at least five hours of moderately intense exercise each week reduced their heart risks by 41 percent. Working out two to five hours weekly resulted in a 32 percent risk reduction, and one to two hours, a 27 percent drop. Studies have further shown that a regular exercise routine can also lower blood pressure, reduce levels of unhealthy blood fats such as triglycerides, and increase levels of "good" HDL cholesterol—providing extra protection against atherosclerosis (the buildup of fatty plaque in artery walls) and heart attacks.
Stroke. When an obstruction develops within a vessel that carries blood to the brain, a person can suffer a stroke. Physical activity in older adults is associated with a substantially decreased risk for such an event. Benefits are particularly striking for those engaging in moderate to vigorous physical activity—they can lower their odds of a stroke by about 60 percent, says Ralph Sacco, chair of neurology at the Miller School of Medicine at the University of Miami. Researchers at Copenhagen University Hospital in Denmark who studied 265 stroke patients (average age 68) found that being active not only reduced the severity of strokes, but also the level of disability experienced two years after an event. Why the good effects? Besides improving cardiac function overall and raising HDL cholesterol, Sacco says, working out makes blood platelets less sticky, lessening the risk of dangerous clots and improving cerebral blood flow.
Depression. Working up a sweat has proved to be an effective weapon against mood disorders at any age, but could be especially important for older people. A 1999 Duke University study showed that a 16-week course of aerobic exercise was as effective as antidepressants in battling depression in people over 50.
Premature death. As part of the Aerobics Center Longitudinal Study funded by NIH, 2,600 men and women age 60 and older had their fitness levels assessed along with weight, body fat, and waist circumference. In studying the mortality rate of participants over a 12-year period, researchers made a striking discovery: Seniors in the least-fit group of participants had a death rate four times higher than the fittest. This research, published in 2007, only confirms what doctors have long said about exercise. If you want to live a long life, the best strategy is to get off the couch now and get moving.