Exercise and aging abilities
Can exercise help the "old, old" stay active and independent? Yes, according to a 16-week study of 64 people, average age 83 (see #4 in the bibliography). The participants were randomly assigned to a twice-a-week fitness program (either walking or resistance training in a gym), or to a control group, which got no organized exercise.
To gauge the effects of exercise, the researchers measured blood pressure, resting heart rate, upper and lower body strength, flexibility, balance and coordination.
While none of the groups had much change in heart rate or blood pressure, the resistance and walking groups both improved on virtually every measure of strength, flexibility and coordination, while the control group improved only on coordination.
Aerobic : Exercise performed below 80 percent of maximum heart rate (defined as 220 minus your age). You are breathing hard, but not gasping for breath. Examples include jogging, cycling, cross-country skiing, tennis and basketball.
Anaerobic: Exercise above 80 percent of maximum heart rate. You have a hard time talking, and cannot long sustain the effort. Examples include sprinting and weightlifting.
Each category has distinct benefits. Aerobic training strengthens the heart, improves oxygen transport to the muscles, and speeds the usage of carbohydrates. Anaerobic training enlarges and strengthens muscles, and can raise the basal metabolic rate -- the amount of energy the body burns at rest, which can help control weight. (To balance things out, however, most people do aerobic exercise for a longer period, which then burns more calories than anaerobic exercise.)
Aware of the swirling debate over the relative merits of aerobic and anaerobic exercise, we asked study author Ross Andel, an assistant professor in the School of Aging Studies at the University of Southern Florida, why both types of exercise produced such similar benefits. Why, for example, would walking improve upper-arm strength nearly as much as an exercise machine? "These people were really old," Andel responded, "and at that age, the benefits of exercise become much less specific; there is a much more universal benefit of just doing something. If you take a brisk walk twice a week, your upper body gets stronger, which you would not see in a younger group. These old, old people are not doing much, period, but younger people are driving cars, going shopping, lifting boxes, strengthening the body constantly."
Although the study did not measure psychological effects, Andel observes that the exercise group had an unusually high retention rate, likely because it conferred social benefits. "When you are in old age, most of your friends are probably gone, and this is a way to meet your peers ... coming together for something in common, staying active a little, talking a little."
The type of improvements Andel observed could help seniors live independently, Andel says. Simple abilities that young people take for granted, like reaching up into a kitchen cabinet, or being able to dress, are critical to independence. "If you don't have a range of motion, or your lower back is too stiff, you might end up in an institution, and you might be able to avoid this with simple exercise."
We asked if one is ever too old to exercise, and Andel responded, "It's almost the older you are, the more important it becomes, but it's always important."
Exercise and the matter of the heart
Remodeling may be good for your house, but it's bad for your heart. As hearts fail, they get larger, their walls get thicker, and their pumping becomes less efficient. This process of "ventricular remodeling" is one reason cardiovascular disease remains the number one killer in the United States.
But now, like a skilled carpenter fixing a botched kitchen makeover, aerobic exercise rides to the rescue of remodeled hearts. In a recent analysis of 14 existing research studies, Mark Haykowsky, _a professor of physical therapy_ at the University of Alberta, found that aerobic exercise shrank the heart and made it pump more efficiently. Strength training did not produce these signs of revitalization, Haykowsky found.
The patients in the 14 previous studies had "stable heart failure," meaning they were short of breath during moderate exercise, but not at rest.
It makes sense that aerobic training would help the heart, Haykowsky says, because exercise opens the blood vessels and "the heart does not have work as hard to pump." At the same time, the cardiac muscles get a better supply of blood and oxygen.
Still, the idea of exercising heart-failure patients is new, Haykowsky says. "Ten or 12 years ago, we would not have exercised these patients, we thought that would worsen their symptoms. Now, we know that the detrimental effects of doing nothing are probably far worse for your whole cardiovascular system."
Too much rest, Haykowsky notes, weakens the muscles and hampers oxygen delivery. "Our views have changed. If you are a couch potato and you improve your fitness, you improve your overall survival. The people with the highest fitness levels live longer, but you do not have to be an Olympic athlete to improve your longevity."
Exercising just to keep from dying
So what's exercise worth in the ultimate coinage -- extra years of life? In 2005, Oscar Franco of Erasmus Medical Center (Rotterdam, Netherlands), looked at low, moderate and high levels of physical activity in people aged 50 and above, and found that moderate physical activity adds 1.3 years of life expectancy, and 3.7 years from high-level activity, beyond the like expectancy of sedentary men. For women, the increases were similar: 1.5 and 3.5 years (see #5 in the bibliography).
Looking at the same issue in a different way, Caroline Richardson, an assistant professor of family medicine at the University of Michigan and an investigator at the VA Ann Arbor Health Care System, studied 9,611 older adults and observed 35 percent fewer deaths among the active ones during an eight-year follow-up.
This benefit was surprisingly large, agrees Richardson, but it makes sense since "the number-one cause of death is cardiovascular disease. When you train your heart, and it gets strong, you are less likely to die of cardiovascular disease."
Still, the results could show that people who start out healthy both exercise more and live longer, without proving that exercise causes increased longevity. This is a common conundrum in epidemiology, and Richardson admits that she cannot rule out the possibility that the correlation does not prove causation.
To reduce the uncertainty, she and her colleagues divided their sample according to their health. "We took all the people who were pretty darn sick, and who thought their health status was poor, and then compared those who did and did not exercise," Richardson says. In an effort to "compare apples to apples," she says, the research group repeated this process for four other health groups.
Intriguingly, the reduction in deaths reached 45 percent among high-risk groups: smokers, or people with diabetes or high blood pressure -- when exercisers were compared to non-exercisers. Building on the idea that people with the worst health may get the biggest benefit from exercise, Richardson is working to encourage walking among people with serious conditions including diabetes, congestive heart failure, and extreme obesity. "These are people, who when they go to a health club, are told, 'We don't want your money, we don't want you to drop dead,'" Richardson says.
Each participant gets a pedometer that can deliver a minute-by-minute count of steps to the researchers. "We set some automated goals," says Richardson, "so if they started at 1,000 steps per day -- essentially just getting up to go to the bathroom -- we increment their goals, until they get up to reasonable amount walking."
Because the core objective is to increase heart and lung fitness, the focus is on "bouts" of walking that last 10 minutes or more, which deliver more cardiovascular benefits than a few brief steps.
Richardson found that 30 of 35 participants completed the six-week study, and that the number of steps in their bouts had roughly tripled since the study began.
Like us, these folks won't soon be heading to the Olympics, but like us, they can still benefit from increased activity...
Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive