The following article comes from the U.S. News ebook, How to Live to 100, which is now available for purchase.
As 10,000 baby boomers a day turn 65, health officials are bracing themselves for a tsunami of chronic ills, from arthritis to osteoporosis. Yet a growing body of evidence shows that regular exercise can delay or prevent many age-related ailments, even among longtime couch potatoes.
"There's compelling data that older individuals participating in exercise programs show dramatic improvement in function and abilities," says Cedric Bryant, chief science officer for the American Council on Exercise in San Diego. In fact, experts suggest that many ills once attributed to normal aging are now being viewed as a result of chronic inactivity.
Despite this promising message, fewer than 5 percent of seniors follow the recommended guidelines for physical fitness (30 minutes of moderately intense exercise on most days). "Levels of activity in people 65 and older haven't budged in decades," says Miriam Nelson, director of the John Hancock Research Center on Physical Activity, Nutrition, and Obesity Prevention at Tufts University in Medford, Mass.
Even if they've never exercised, the middle-aged and older can still benefit by beginning now. Experts say sedentary people will actually fare better in percentage gains relative to active people, since they're starting from zero. "It doesn't matter how old you are," says Colin Milner, founder and CEO of the International Council on Active Aging in Vancouver, British Columbia. "It's never too late to start exercising."
Exercise may also benefit the body in ways we can't see: deep within our cells. A growing pile of evidence suggests it changes the way DNA behaves—for the better. For example, a single 20-minute workout appears to help tune-up DNA, allowing muscles to work better and more efficiently, according to a recent study published in Cell Metabolism. And encouragingly, a study published last year in PLoS Medicine found that people who are genetically predisposed to obesity can trump their DNA by exercising for about 30 minutes five days a week.
So, will exercise make you live longer? Hard to say. But those who exercise regularly will generally see a drop in their risk for many of the diseases and disabilities tied to aging. Consider:
Arthritis. If you suffer from the pain and stiffness of osteoarthritis, becoming more active may seem like the last thing you want to do. But increasingly, research suggests it could be one of the best strategies for feeling better, especially when it comes to sore knees—a common occurrence in older people. "Almost all studies show that exercise reduces pain and disability if it's done at a level that does not cause unusual pain during the workout, and no data show it's harmful," says N. John Bosomworth, clinical instructor in the Department of Family Practice at the University of British Columbia in Vancouver. Bosomworth says his 2009 peer-reviewed analysis of current research also found that the exercise benefit is roughly equivalent to the continuous use of nonsteroidal anti-inflammatory drugs, such as ibuprofen.
Dementia. "Exercise can keep your brain sharp," says Milner. Indeed, its effect on brain fitness is drawing the scrutiny of researchers. In a 2006 study by the Group Health Research Institute in Seattle, higher levels of physical activity were associated with a 30 to 40 percent reduction in the risk of dementia and Alzheimer's disease in people age 65 and up. "In our study, as little as 15 minutes a day, three times per week helped maintain the brain," says lead investigator Eric Larson, an internal medicine doctor and geriatric researcher.
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.
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.