If you find yourself struggling, three new studies might rekindle your motivation. All conclude that midlife (and older) adults can sustain an exercise routine and gain a range of health benefits.
The most remarkable of the papers, "Reversing the Cardiac Effects of Sedentary Aging in Middle Age," was published in Circulation, the journal of the American Heart Association. It went where no previous exercise study has gone, lasting two years rather than the more customary three to four months. The researchers employed a randomized, prospective design with both an experimental group and controls. For precision results, they probed into their subjects' heart ventricles.
Individuals in the exercise group, who had an average age of 53 when they started working out after years of sedentary living, increased their aerobic fitness by 18 percent. They also improved their cardiac compliance, or elasticity, by 25 percent.
The improvement in cardiac elasticity was deemed particularly noteworthy, as it had never been seen before in midlife adults. Loss of elasticity is a major cause of heart failure, which results in many hospitalizations and deaths in the over-65 population.
"The biggest and most surprising result of our study was the magnitude of the increased cardiac compliance," said Ben Levine, senior author and director of the Institute for Exercise and Environmental Medicine in Dallas. "A 25 percent increase in cardiac elasticity is huge. It allows the heart to fill more easily and pump more blood."
The control group practiced yoga, balance exercises or strength training three times a week for two years — much more than many inactive adults. Yet their aerobic fitness declined by 3 percent, and their cardiac compliance didn't change.
"This was a very sophisticated study, even a sensational one," commented Paul Thompson, a cardiologist at Hartford Hospital in Connecticut. Thompson was not involved in the study but has been conducting heart and exercise research for four decades.
In earlier studies, Levine had shown that older athletes have roughly the same degree of cardiac compliance as young adults. However, he had also discovered that regular exercise couldn't increase the cardiac compliance of subjects over 65. Now he believes he has found the "sweet spot" in time when adults can still enhance their heart function: from ages 45 to 64.
"We have demonstrated that if you incorporate regular exercise into your daily life, starting no later than middle age, you can restore the youthfulness of your heart muscle," he says.
Levine's subjects followed an exercise program similar to those used by serious athletes, beginning with low-intensity "base training" workouts three times a week for 30 minutes each. After four weeks, the subjects began using a little more effort. Later, they added interval training to their regimen, and one weekly longer workout of at least 60 minutes. During peak training, they worked out four or five times a week for about 180 minutes in total — 30 minutes more than the minimum standard of 150 minutes per week recommended by many fitness guidelines.
Some would judge this program too hard and time-consuming for many busy adults. Levine disagrees, noting that his subjects completed 88 percent of their assigned workouts, with nearly a quarter hitting 97 percent.
"Exercise is so important that people should think of it as part of their personal hygiene, like brushing their teeth," he says. "Our program isn't difficult to incorporate into your life. You should do one fun activity for at least an hour on the weekend, and one hard activity for 30 minutes after your second cup of coffee another day. Then, on another two or three days, exercise for 30 minutes while you're watching TV."
Another new research report, from Mayo Clinic Proceedings, tracked changes in fitness and mortality among more than 6,000 men and women who were, on average, in their late 40s at the outset. Those who maintained or improved their fitness over 4.2 years had a 40 percent lower mortality rate than those who lost fitness due to insufficient activity.
While 65 may represent an upper age limit for changes to heart function, consistent exercise can offer other health payoffs to older adults. A study just published in the American Journal of Preventive Medicine investigated the walking habits of 139,000 Americans who were nearly 71 years old, on average, when first monitored. Thirteen years later, those who reported little to no weekly walking had died at a rate 26 percent higher than those who walked regularly, but for less than two hours a week. Those who walked two to six hours a week had a mortality rate 36 percent lower than the under-two-hour walking group.
"Walking is simple, free, and does not require any training," the researchers concluded. "Thus it is an ideal activity for most Americans, especially as they age."
Levine agrees. "Exercise supplies many benefits that can be achieved even if it is started later in life and at low doses," he says. "I ask my patients: If there was a pill that could increase your strength, balance, and endurance while reducing the risks of heart disease, diabetes, hypertension, Alzheimer's and many cancers, would you take it?"
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