Getting inactive middle-aged women and men to stick to an aerobic workout may reduce or reverse their risk of heart failure, a new study shows.

Sedentary people — such as those who spend hours sitting while working or lying on the couch while watching TV — are at greater risk of having their heart muscle shrink and stiffen in late-middle age, which can increase their risk for heart failure.

It wasn’t known if this heart stiffness could be stopped or reversed. To find out, researchers randomly assigned a group of more than 50 sedentary women and men between the ages of 45 and 64 to an aerobic exercise training program or to a yoga, balance and strength training program. The participants exercised for two years.

In the study, published Monday in the American Heart Association’s journal Circulation, the aerobic exercise group took part in high- and moderate-intensity aerobic exercise at least four days a week. This included, for example, four sets of four minutes of exercise, at 95 percent of their maximum heart rate — the hardest they could exercise for four minutes. This intense activity was followed by three minutes of recovery at 60 percent to 75 percent of their peak heart rate. The other group did yoga, balance training or weight training three times a week.

The researchers conducted tests to assess heart health at the beginning and end of the study. They found that the individuals assigned to the aerobic exercise program showed significant improvements in how their body used oxygen and had less cardiac stiffness — two markers of a healthier heart. Among the women and men who took part in the yoga, balance and strength training program, cardiac stiffness and the body’s use of oxygen remained unchanged.

By American Heart Association News