Odgovor So mar 17, 2018 16:18

Hearts Get 'Younger,' Even At Middle Age, With Exercise

Hearts Get 'Younger,' Even At Middle Age, With Exercise

As early as your mid-40s, especially if you're sedentary, your heart muscle can show signs of aging, losing its youthful elasticity and power. But moderately strenuous exercise can change that.

Eventually it happens to everyone. As we age, even if we're healthy, the heart becomes less flexible, more stiff and just isn't as efficient in processing oxygen as it used to be. In most people the first signs show up in the 50s or early 60s. And among people who don't exercise, the underlying changes can start even sooner.

"The heart gets smaller — stiffer," says Dr. Ben Levine, a sports cardiologist at University of Texas Southwestern Medical Center and director of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital, in Dallas.

Think of the heart muscle as a rubber band, Levine says. In the beginning, the rubber band is flexible and pliable. But put it in a drawer for 20 years and it will emerge dry and brittle.

"That's what happens to the heart and blood vessels," he says. And down the road, that sort of stiffness can get worse, he notes, leading to the breathlessness and other symptoms of heart failure, an inability of the heart to effectively pump blood to the lungs or throughout the body.

Fortunately for those in midlife, Levine is finding that even if you haven't been an avid exerciser, getting in shape now may head off that decline and help restore your aging heart. He and his colleagues published their recent findings in the American Heart Association's journal, Circulation.

The research team recruited individuals between the ages of 45 and 64 who were mostly sedentary but otherwise healthy.

Dallas resident Mae Onsry, an accounts payable manager, was 62 at the time. Raising two children and working full time, she says, she never had the flexibility to fit in exercise, although she knew it was important for her health.

"I have my hobbies," says Onsry, including ballroom dancing and gardening. But it was nothing routine, nothing "disciplined," she says.


Participants were randomly assigned to one of two groups. The first group engaged in a program of nonaerobic exercise — basic yoga, balance training and weight training — three times a week. The other group, which Onsry was in, was assigned a trainer and did moderate- to high-intensity aerobic exercise for four or more days a week.

After two years, the group doing the higher-intensity exercise saw dramatic improvements in heart health.

"We took these 50-year-old hearts and turned the clock back to 30- or 35-year-old hearts," says Levine. Their hearts processed oxygen more efficiently and were notably less stiff.

"And the reason they got so much stronger and fitter," he says, "was because their hearts could now fill a lot better and pump a lot more blood during exercise."

The hearts of those engaged in less intense routines didn't change, he says.

A key part of the effective exercise regimen was interval training, Levine says — short bursts of high-intensity exercise followed by a few minutes of rest. The study incorporated what are often referred to as 4x4 intervals.

"It's an old Norwegian ski team workout," Levine explains. "It means four minutes at 95 percent of your maximal ability, followed by three minutes of active recovery, repeated four times."

Pushing as hard as you can for four minutes stresses the heart, he explains, and forces it to function more efficiently. Repeating the intervals helps strengthen both the heart and the circulatory system.

"The sweet spot in life to get off the couch and start exercising [if you haven't already] is in late middle age when the heart still has plasticity," Levine says. You may not be able to reverse the aging of the vessels if you wait.

https://www.npr.org/sections/health-sho ... h-exercise
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