They found a two-year program roughly following the American Heart Association's exercise guidelines helped a pack of middle-aged adults tune up their hearts and lower their risk of heart failure.
And the loafers liked it, or at least most of them did.
"I feel younger every day," said Lisa Ashworth, a 55-year-old pharmacy specialist from Dallas who completed the trial and who says she's now committed to regular exercise.
"We found that exercising only two or three times a week didn't do much to protect the heart against aging,” said Dr. Benjamin Levine, director of the Institute for Exercise and Environmental Medicine at Texas Health Resources and the University of Texas UT Southwestern Medical Center in Dallas.
“But committed exercise four to five times a week was almost as effective at preventing sedentary heart aging as the more extreme exercise of elite athletes,” Levine added.
Levine’s team recruited 53 middle-aged volunteers aged 45 to 64 who admitted to loafing around a lot, and put them on an exercise regime. Some were assigned to an exercise program that included moderate and high-intensity workouts, and some got weight training, balance work and yoga.
After two years, the results were clear. Those who had worked out at least four days a week had healthier hearts and arteries, and were fitter as measured by oxygen uptake, the team reported in the journal Circulation.
Those who did the yoga and weight sessions did not become fitter.
“This study demonstrates that prolonged (two years) exercise training, initiated in middle age, can forestall the deleterious effects of sedentary aging by reducing cardiac stiffness and increasing fitness,” the researchers wrote.
The volunteers all did exercises they chose and that they could stick with, Levine said.
“We are quite careful to actually diversify the kinds of exercise they do,” he said. “In order to minimize overuse injuries and keep people fresh, we like to encourage diversification,” he added.
“First, it has to be something they have access to, second it has to be something they enjoy and third it has to be alternating impact and low impact. It could be treadmill exercise. It could be cycling. It could be an elliptical. It could be swimming.”
Most volunteers chose to run, walk or cycle, he said.
The volunteers were not simply tossed onto a track and told to run. They worked up gradually to get their hearts pumping and were told how to measure their exertion.
“Everyone got a heart monitor rate monitor and we were very specific about the heart rate zones that were required,” Levine said.
'Sweet spot' of exercise
The team employed standards and techniques used to train athletes, but modified for the average, flabby American. This included at least one long session a week of tennis, dancing or brisk walking; one high-intensity aerobic session that could be as short as 20-30 minutes; one or two weekly strength training sessions and two to three days of moderate intensity exercise such as a moderate walk. The goal with the last is to break a sweat, but not get out of breath.
“We found what we believe to be the optimal dose of the right kind of exercise, which is four to five times a week, and the 'sweet spot' in time, when the heart risk from a lifetime of sedentary behavior can be improved — which is late middle age,” Levine said.
“The result was a reversal of decades of a sedentary lifestyle on the heart for most of the study participants.”
The intense workout was important, Levine said, even if it was just once a week.
“It breaks up the monotony of just the walking,” he said. “Most people really enjoy the high intensity work. You would think that they wouldn’t but they like the fact that it’s short and they like the fact that they feel stronger afterwards."
Ashworth said it was hard at first. "I can tell you when we first started the study, when I started jogging, I felt like my heart was going to pound out of my chest," she said. "About midway through I hit my stride."
"I learned really to get my heart rate up. It’s getting that sweat going," she said. "Getting that garbage out of your body."
She pulled a muscle and backed off for a while, but then resumed the exercise. Ashworth said she'd been a dancer as a child and joined in the aerobics crazes of the '80s, but gradually became an average, sedentary American.
Now, she parks on the second floor of the parking garage at the hospital she works in and walks up to the eighth floor to her office. She uses a rowing machine, cycles and jogs occasionally with her husband and her dog.
So can people just slack off again after two years of regular workouts? “We didn’t study that,” Levine said. “My bias is to say no. It has to be part of your personal life."
Also, the exercisers kept the pounds off, the researchers said. And Ashworth found other benefits.
"Exercise is great for stress. Really," she said.
A second study published Monday suggests that it's never too late to exercise.
A team at Tufts University wanted to see if frail, elderly people could up their game with some exercise.
They found that people as old as 89 could tolerate an exercise regime that included walking, leg lifts and stretching. They may have stayed frail, but improved in ways that can really make a difference, such as being able to get up out of a chair, and walk a few hundred feet.
"Even if you are at a really debilitated state, you can benefit from a physical activity program," said Roger Fielding of Tufts, who led the study published in the Annals of Internal Medicine.
"This is the kind of exercise that just about anybody could do in any setting — the community center, their apartment, in a very small room," he said. "You are never too old, or never too weak or never too impaired."