Osteoporosis. Falls and broken bones often spell the difference between living independently and having to rely on assistance. Research indicates that exercise can prevent these setbacks by building stronger bones and lowering the risk of fractures. In a 2010 study, researchers compared women 65 and older who participated in an exercise regimen with peers who instead joined general wellness classes. Among the 227 women who completed the study, those who worked out showed significant increases in bone mineral density (BMD) in the spine and hips and a 66 percent reduction in the rate of falls. What's more, fractures due to falls were half as common in the exercise group as in the control group. In general, aerobics, weight-bearing activities (for example, walking, running, or stair climbing), and resistance exercises (which require the person to resist a particular force, like pulling against rubber tubing or lifting a dumbbell in a triceps curl) are all effective in increasing BMD in the spine.
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.