RACHEL MARTIN, HOST:
All right. If you haven't been an avid exerciser, never fear. It's not too late, necessarily. A recent study shows that if you take up routine exercises even in late middle age, you can actually reverse some of the damage that a sedentary lifestyle does to your heart. Here's NPR's Patti Neighmond.
PATTI NEIGHMOND, BYLINE: By your mid-40s, your heart may start to show signs of aging, especially if you don't exercise regularly. Cardiologist Ben Levine.
BEN LEVINE: The heart gets smaller and stiffer.
NEIGHMOND: And eventually it doesn't pump blood as efficiently as it used to, making some activities difficult.
LEVINE: The pressure inside the heart goes up really high, and the blood will back up into the lungs, making people very, very short of breath.
NEIGHMOND: Levine studies exercise and fitness at the University of Texas Southwestern Medical Center. He wanted to know if starting routine exercise in midlife or even later could prevent this decline in the heart. He recruited patients between 45 and 64 who were otherwise healthy but did not exercise. Mae Onsry (ph) was 62 at the time.
MAE ONSRY: I have my hobbies - I do ballroom dancing - in my leisure time that I like. And I do gardening.
NEIGHMOND: Enjoyable, but not a daily routine.
ONSRY: No discipline.
NEIGHMOND: Onsry was one of 53 volunteers in Levine's study who were divided into two groups. One did weightlifting and yoga three days a week. Onsry was in the other group which did moderate to high-intensity exercise most days of the week. After two years, the group doing the more frequent, higher intensity exercise saw dramatic improvements in heart health.
LEVINE: We took these 50-year-old hearts and turned the clock back to 30- or 35-year-old hearts.
NEIGHMOND: Their hearts processed oxygen more efficiently and were notably less stiff.
LEVINE: And the reason that they got so much stronger and fitter was because their hearts now could fill much better and pump a lot more blood during exercise.
NEIGHMOND: The hearts of those doing less regular exercise didn't change. For Mae Onsry, the study was life changing. Today she exercises every day of the week, walking and jogging at least five miles. If she misses a day, she says she just doesn't feel good. And it's helped her mental health, too.
ONSRY: I'm not moody. I mean, I'm happy.
NEIGHMOND: A key part of the exercise regimen was interval training, short bursts of high-intensity exercise followed by a few minutes of rest. For example, Levine says, this four-by-four interval training.
LEVINE: It's an old Norwegian ski team workout. It means four minutes at 95 percent of your maximal ability followed by three minutes of active recovery, repeated four times.
NEIGHMOND: Pushing as hard as you can for four minutes stresses the heart and forces it to function more efficiently. Levine says if you haven't done high-intensity exercise and decide to start, make sure you build up gradually. Cardiologist Nieca Goldberg, spokesperson for the American Heart Association, says Levine's findings are important.
NIECA GOLDBERG: Many studies that are done that look at cardiovascular health look at improvements in risk factors for heart attack and stroke, such as high blood pressure, high cholesterol and diabetes. But this study specifically looked at heart function and how heart function can improve with exercise.
NEIGHMOND: Goldberg says the findings are a great start. But the study was small, and it needs to be repeated with far larger groups of people. Patti Neighmond, NPR News.
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