Traditionally, heart patients were encouraged to begin slowly and work up to more strenuous activity. New research suggests rigorous workouts benefit heart patients. According to The Wall Street Journal:
Some scientists and clinics are backing the use of high-intensity interval training, which involves short spurts of intense exercise at 85% to 95% of maximum heart rate alternating with periods of moderate exercise. Heart patients have traditionally built up fitness with steady sessions of aerobic exercise aimed at keeping the heart beating at about 70% of its maximum rate. That’s meant to give the heart a workout without risking chest pain or a cardiac event.