By Ellen Walker Ternes

Exercise and Aging

Back in the ’70s, when kinesiology professor Jim Hagberg started doing some of the nation’s first research on how exercise affects aging, there wasn’t a lot of evidence that exercise made much difference in the health of people over 60.

One of Hagberg’s first studies would blow that misconception sky high. “We looked at older athletes who ran 30 miles a week,” Hagberg says, “and found that physiologically and metabolically, these folks looked like they were in their 20s.”

Today, Hagberg and fellow faculty in the School of Public Health’s Department of Kinesiology are national leaders in research on exercise and aging. Ranked third in the nation, the department is also one of only two centers in the country that study how genes affect the way people respond to exercise.

Hagberg and his colleagues have compiled data that show, without a doubt, even moderate, regular cardiovascular, resistance and balance exercise can slow, or even reverse, the effects of aging. And, unfortunately, they’ve found that some of those unhealthy aging demons also return almost as soon as you dump the workout for the couch.

While Hagberg’s early study of unusually fit people was good news, there were bigger questions about how the average person responds to exercise. “So we got older folks, aged 60-69, who had been sedentary and put them through training,” Hagberg says. “They improved dramatically. In terms of cardiovascular fitness, they had turned the clock back almost 20 years, with three days a week of 40- 50 minutes of moderately high intensity exercise.” Then Hagberg started measuring risk factors, things that get worse as we get older: high blood pressure, type 2 diabetes, cholesterol. The results, again, were almost startling, with good news and bad. After seven days of 40 minute workouts, formerly sedentary people with type 2 diabetes saw glucose levels drop to normal. The bad news? “Ten days after people stopped exercising, their glucose levels looked like those of a sedentary person again,” says Hagberg. Hagberg’s hypertension studies with older subjects show benefits from walking three times a week. And the number of endothelial progenitor cells, which help heal blood vessel damage caused by heart disease, increased with exercise, then quickly decreased when exercise stopped. Hagberg is now looking at “genetic misspellings that identify people who will respond the best to exercise training, in ter ms of reducing blood pressure or treating other conditions.”

It’s natural to lose muscle as we age. Women start in their 40s, men their 50s, losing 6 percent of their muscle mass and 12 percent of strength a decade. Muscle mass loss, a condition called sarcopenia, “can have profound consequences in older people,” says kinesiology’s Ben Hurley. “There is a high mortality rate from things like falls that can be related to muscle loss.” When Hurley’s group started looking for the genes that determine how muscles respond to exercise, Hurley thought they would identify a few genes that did all the work. Instead, they found a complex biological pathway that will take, Hurley says, a lot more work to unravel. What Hurley’s group has confirmed with research, however, is that 30 minutes of resistance exercise, three times a week can reverse muscle loss in older people in a short time. “In the first two months of training, you can increase muscle mass by 12 percent,” Hurley says. “Regular resistance exercise will help you maintain that.”

John Jeka asks his volunteer subjects, many of them 70 or older, to climb into what he calls the “virtual cave,” where they get strapped into a harness to see how stimuli like moving lights and tilting foot boards affect their balance. But in the real world, where there is no harness, losing balance becomes a greater risk with aging. Falls and their complications are a leading cause of death in people over 65. Says Jeka, “One of the difficulties with balance is that it’s multifaceted, not just related to a single factor. So we’re looking at how to improve the balance itself, not all the conditions that might cause it.” Working with Michael Pecht in the Department of Mechanical Engineering, Jeka is developing a sensor system of small devices worn in the ear and on the ankle to prevent falls. In the meantime, Jeka says exercise can help reduce loss of balance. “For anyone over 50, balance exercise should be included in their workout routine. Balance has to be continually challenged, yet safe. I think within the next 20 years, all health clubs will have balance machines.”

Steve Roth looks at the big picture of what he describes as “how our genetics set us up for our life paths,” especially in regard to exercise. Roth was surprised with one result of his research into dna changes that exercise brings about. He knew that telomeres, age-buffering elements of dna that help cells reproduce, shrink in length as we get older. Roth’s team discovered that people who exercise have longer, or “younger,” telomeres than sedentary people. The surprise was that moderate exercisers also had younger telomeres than master athletes. “This fits a lot of emerging data that moderate rather than extreme physical activity is a benefit,” Roth says.

The day when a doctor can prescribe an exercise-medication regimen based on your personal genome is not that far off. Even then, the biggest challenge, say all of these researchers, is figuring out how to get people to exercise in the first place. “We know exercise is beneficial for so many things,” Roth says, “yet 40 percent of the population is sedentary. No one has come up with a successful strategy for motivating people to exercise.” See the Winter 2007 issue of Terp for a story on kinesiology professor Bradley Hatfield’s research that shows exercise also helps the aging brain, even delaying symptoms of Alzheimer’s disease. TERP

Break

Keep you brain and your body young, with these tips courtesy of kinesiology doctoral candidate Jo Zimmerman, a certified health and fitness instructor:

In your 20s and 30s, when you’re juggling career and family, fit activity in and do things together. Get off the Metro one stop earlier or walk at lunch. Join a fitness club or play a team sport after work.

In your 40s and 50s, bank on maturity by rebalancing priorities for your own health. Get health screenings. Try new games or activities to keep your outlook fresh and your brain and body working.

In your 60s and 70s, create new networks to maintain your social health and an independent life using strength, aerobic and flexibility exercises.

In your 80s and beyond, keep going. Respect your bones by trying yoga, weights, Pilates and swimming.

Want to learn more?

Join the University of Maryland Alumni Association now to automatically receive Terp Magazine and to stay connected to the University of Maryland community.