Failed love affairs notwithstanding, time can take a real toll on your ticker. Sedentary middle-aged adults can end up with stiffening in the heart muscle, particularly the left ventricle (the chamber that pumps oxygen-rich blood to the body), raising the risk for heart failure. Masters athletes of the same age, by contrast, have large, compliant left ventricles similar to those of their younger peers.

Now, groundbreaking research shows that people can reverse age-related heart damage, but they need to make regular aerobic exercise—like cycling—a part of their daily lives before it’s too late.

In a recent study published in Circulation, cardiologists at UT Southwestern and Texas Health Resources had 53 sedentary adults, ages 45-64, either perform a cardiovascular exercise program for two years or act as a control group, participating in yoga and balance training over the same period. After a gradual three-month buildup, the cardio group ultimately worked out four to five days a week and for 30 minutes at a time, including one high-intensity interval workout and one longer session.

After two years, the cardio exercisers boosted their VO2 max (the maximum amount of oxygen they could use) by 18 percent and improved the elasticity of their left ventricle muscle by more than 25 percent. Their peers in the control group, meanwhile, saw no improvements.

Importantly, previous research by this team found that age and exercise frequency matter for those seeking to reverse heart damage. Like the study group, you need to exercise at least 4-5 days a week. Anything less won’t have the same impact. You also need to start before age 65, after which the heart appears to lose too much of its plasticity to remodel itself.

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As for what exercise works best, cycling is high on the list.

“We are big fans of cycling as a key mode to include in any long-term exercise program,” says senior study author Benjamin Levine, a professor of Internal Medicine at UT Southwestern. “It can be done outside, on the road or trail, or inside on a cycle ergometer [stationary bike].” Cycling, therefore, is not only effective, but also fun and accessible.

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