Dr. Al Sears. Sears—a medical doctor, nutritionist and leading thinker in the field of integrative health—believes everything we think we know about cardio is just about 100 percent incorrect.
Sears believes that the key to effective exercise for weight loss and overall health is not duration but intensity. He thinks the long slow constant speed aerobics that we’ve all been trained to believe is so good for us is exactly the wrong thing for us to be doing.
“After 30 years of working with extremely fit athletes, patients with failed, diseased or injured hearts and average people in between, one thing is apparent: doing continuous cardio exercise is a waste of time”, he says.
For many people in the exercise community those are fighting words. But Sears backs them up with some strong scientific arguments. “(Long slow constant cardio) just doesn’t build what your heart needs”, Sears says. “It doesn’t increase your heart’s ability to respond to real demands. In fact, for all your effort, you only reduce your ability to handle life’s stressful circumstances—the last thing you want!”
Sears points to the Harvard Health Professionals Study which followed over 7,000 people and found that the key to exercise is not length nor endurance but intensity. According to that highly regarded study, the more intense the exertion, the lower the risk of heart disease. “When you exercise for long periods at a low to medium intensity, you train your heart and lungs to get smaller in order to conserve energy and increase efficiency at low intensity”, says Sears. “Intensity is the key”.
Sears is one of the most outspoken critics of long slow aerobics, but he is hardly the only one. There has been quite a lot of research in the last few years showing the clear advantage of interval training (which is by definition high intensity) over long slow aerobics, not only from the point of view of health measures (like VO2 max) but also in terms of fat loss.