Telling heart patients to really push themselves during exercise sounds risky. But a growing body of research suggests that a workout routine athletes use to get in shape may do the same for some patients.
Some scientists and clinics are backing the use of high-intensity interval training, which involves short spurts of intense exercise at 85 to 95 percent 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 percent of its maximum rate. That's meant to give the heart a workout without risking chest pain or a cardiac event.
Using intense exercise with patients suffering from heart failure and coronary artery disease, and those recovering from bypass surgery and heart attacks, is still controversial. Even proponents of the approach say more research is needed. But studies to date suggest that intense interval training improves the ability of the body in at least some patients to transport and use oxygen—which is generally associated with living longer—more effectively than a steady, moderate workout. The technique is also being studied in people with hypertension, diabetes and other conditions.
Intense interval training is commonly used by athletes to increase their speed and endurance. Alternating the hard work with periods of more moderate exercise enables them to accumulate the benefits of an intense workout.
"What our group has done is to train these patients a bit harder," said Trine Moholdt, a postdoctoral fellow at the Norwegian University of Science and Technology.
Her team presented a 107-patient study at a scientific meeting last fall in Stockholm. It showed a cardiac-rehab program that included supervised high-intensity treadmill workouts improved peak oxygen uptake better than a standard moderate-intensity program that burned the same number of calories.
Ray Squires, program director of cardiovascular health and rehabilitation at the Mayo Clinic in Rochester, Minn., has been using high-intensity intervals in patients for about four years.
"There's been a natural progression over time of what we've thought exercise for patients with cardiovascular disease should be," said Squires. "If you go back 50 years, people were told to hardly do any exercise for weeks after a heart attack. Gradually we learned that was wrong."