The next wave of aging

Slowing down with age doesn’t have to happen as drastically as it usually does, say Marquette University researchers. Here’s how they’re unlocking a secret to curbing physical decline.

By Erik Gunn

Marquette University biologist Dr. Robert Fitts spent most of his professional life studying how human muscles wither in zero gravity. Working with NASA and international space organizations, he helped combat the muscle atrophy that plagues astronauts.

Now he has turned to a related problem: Why do people fatigue so easily when they get older, and what can be done to prevent that?

It’s a question that his colleague, Dr. Sandra Hunter, has also been considering during a career working with athletes while paying special attention to the exercise needs of the elderly.

Fitts is a professor of biological sciences in the Klingler College of Arts and Sciences and Hunter a professor of exercise science at the College of Health Sciences. Together they are teaming up on a five-year project that will explore if certain exercise techniques can help aging adults stay stronger — longer.

Funded by a $2.8 million National Institutes of Health grant, the project will combine the everyday with the cutting edge. Two groups of people in their 70s and 80s perform a traditional strength training program or a program designed to stress the muscle for a long period. That’s the familiar part.

The cutting-edge part will be the use of high-tech tools to examine the muscle cells and nervous system of the two groups to find out what difference the workouts made.

Dr. Robert Fitts, 73, says slower lifting of moderate loads can dramatically increase muscle power in older people.

But isn’t slowing down just the price of growing older? Not necessarily, says Fitts. At least nowhere near as drastically as it does.

“I think that’s sort of a defeatist attitude to say, ‘Well, we’re all getting old … forget about it,’ ” he says.

Hunter’s own doctoral research showed her how much staying active can help older people preserve strength and stamina. She studied a sample of about 250 women, dividing them into more active and less active groups.

For those who were less active, simple tasks such as getting out of a chair could require a large percentage of their strength by the time they were 63 years old. The active women didn’t reach that limit until they were 73, on average. “They had a 10-year advantage,” she says of that group.

Our younger selves may not fully appreciate the difference. “When you’re young, performing daily activities of living is easy because you’ve got to use such a small percentage of your strength,” Hunter continues. “As you age, you become so much less strong, but if you’re active you can offset some of those limitations.”

The pair thinks it’s the muscles themselves — and learning how to exercise them most effectively as we age — that hold the key.

Strength training for older adults was once seen as out of the question by many medical professionals, but Hunter points out that, since the 1990s, it has increasingly become recognized as a key to better health and functioning for everyday living. The project aims to fine-tune that principle with an eye toward developing routines better suited to the physiology of the aging body.

Our muscles fall into two general categories: in layman’s terms “fast” and “slow” muscle fibers, Fitts explains. When we’re young, a combination of fast and slow muscle fibers is prevalent in our musculature.

As we age, the slow fibers increasingly dominate. And the two groups of muscle fibers can respond differently to training. The standard workout practiced by everyone from teenage swimmers or football players to active middle-age gym rats — rapid lifts and squats and other actions with heavy weights — trains their fast muscle fibers well. But for the slow muscle fibers dominant in the elderly, that style of exercise doesn’t work, says Fitts. They need slower movement.

Dr. Sandra Hunter’s research shows that staying active can confer a 10-year advantage

This isn’t just yoga or tai chi. The muscles still need to be taxed — “loaded” — during exercise.

Taxing doesn’t mean straining, though. The most effective weight exercises only require people to push about 30 percent of the maximum load of which they’re capable, not the 80 percent that you might see the ambitious try to push at a health club.

“If you lift at 30 percent of your max load, you actually will get more power over time than you would with the 80 percent load,” Fitts says.

Two groups of older adults will take part in the study. One group will do traditional leg muscle training with weights equivalent to 80 percent of their maximum capacity at normal speed, so 1 to 2 seconds per lift. The second will use less weight, 30 percent of maximum, and far more slowly. Instead of typical eight-repetition intervals, they’ll lift for as many repetitions as they can in a single round.

Before and after the training, the researchers will compare strength, as well as fatigue in the nervous system and in the muscle using a variety of instruments and techniques: transcranial magnetic stimulation, magnetic resonance spectroscopy and magnetic resonance imaging, and muscle biopsies, studying single muscle fibers for their contractile function and metabolic characteristics, Hunter says.

Hunter and Fitts have long crossed paths in their work at the university but had never before worked jointly on research. Now, their disparate disciplines are helping the project span a range of research areas. Hunter’s team will work directly with human subjects who will learn a collection of new fitness techniques.

Fitts, working primarily at the laboratory bench, will focus quite literally on human tissues of the research subjects and how they change in response to aging and exercise. “It was a natural collaboration,” Fitts says.

Other collaborators at Marquette are Dr. Alexander Ng, associate professor of exercise science; Dr. Mehdi Maadooliat, assistant professor of mathematics, statistics and computer science; and Dr. Carolyn Smith, clinical professor of physical therapy and executive director of the Marquette University Medical Clinic. An additional team based at Ball State University will examine molecular biological data. Marquette undergraduate and graduate students will also take part by working on the various research teams based here.

Both find a certain personal resonance in the work. Hunter — who has competed in many triathlons — has gravitated to working with older people since first making the transition from gym teacher to the academic world of exercise science in her native Australia.

Having worked with older patients during and since her graduate studies, she has come to deeply appreciate their distinctive traits and the stories she hears from them, not to mention their punctuality. “They turn up early to appointments!” she says with delight.

For Fitts, who still maintains an active running regimen and does regular weight training at the age of 73, there’s a striking contrast between their project and the work that seems to dominate the research agenda in the world of athletic training.

“You’ve got lots and lots of people working to try to get the world-class athlete to get 1 second better,” he says. “But you can double the force of an older person with the right type of training.”

Listen to an interview with Hunter and Fitts on WUWM’s Lake Effect program. Image by Dirk Unger, CH.

“The next wave of aging” is adapted from the 2016 issue of Marquette’s Discover magazine, where you’ll find more great stories about research, scholarship and innovation at Marquette.
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