Ask the doctor: Best way to work out
Q. What is better for my heart—a fast run on the treadmill for 10 minutes or 30 minutes of light cycling on a machine?
A. The benefit of exercise on heart health depends on the dose; in other words, the more the better. So, my answer to your question is "Why not do both?" Exercise of virtually any kind prevents heart attacks, strokes, high blood pressure, and diabetes.