From the WSJ: To Heal a Heart, Train Harder
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.
This is unsurprising — part of the cause of heart disease is not exercising our aerobic systems hard enough. The heart is a muscle – it responds to moderate pushing just the way our other muscles do. And as a muscle, it also receives benefits from aerobic exercise, just the way our other muscles do, in the form of more oxygen and better blood supply. So if you push it within its limits, you are helping it.
And while the heart is getting stronger through that aerobic exercise, the benefits from the exercise itself cause many positive changes throughout the body that help it get healthier and stay healthier — more oxygen in the blood, better blood flow throughout the entire body from newly opened capillaries, increased lung capacity, etc.
We knew all this from Dr. Ken Cooper’s classic “Aerobics” written in 1968.
So this research appears to be another nail in the coffin for the idea that walking is just as good as running, or other forms of more intense aerobic exercise. It plainly is not, even for heart patients.
The article also mentions potential benefits for people at risk for diabetes: by training both fast-twitch and slow-twitch fibers through interval training, you increase the capacity of the muscles to take up the additional glucose in the blood. So that is excellent news too.