High-intensity interval training versus moderate-intensity continuous training in cardiac rehabilitation

Researchers combined 10 small trials involving 337 adults in cardiac rehabilitation, mainly people with heart disease. One group did high-intensity interval training, which means short bursts of hard exercise mixed with easier recovery periods. The other did moderate-intensity continuous training, meaning steady exercise at a manageable pace. The interval-training group generally improved aerobic fitness, or the body’s ability to use oxygen during exercise, by a small amount more. The studies did not show clear differences in quality of life or heart pumping ability.

What this means for you: Short, harder exercise may improve fitness slightly more than steady exercise, but it is not clearly better for living longer or avoiding heart problems. Choose the style that is safe, supervised, and realistic for you, especially if you have heart disease.