Which develops VO2 max more effectively: long runs done within a lower heart rate zone, or high-intensity training, i.e. sprints? Or does it depend on the individual?
For those who aren’t physiologists or exercise geeks, VO2 max is shorthand for maximal oxygen uptake, a standard measure of aerobic fitness. About half of anyone’s VO2 max is innate, genetics studies suggest; you’re born relatively more or less fit. The rest is up to you.Until recently, most experts believed that to improve fitness, you needed to complete lengthy runs or other endurance workouts. But lately, some have begun to swear by short bursts of extremely taxing exercise, a routine known as high-intensity interval training. Whether one is more effective than the other at building endurance, though, remains in dispute. ‘‘There is not a lot of scientific literature” directly comparing the two, says Martin Gibala, chairman of the department of kinesiology at McMaster University in Ontario.
He, however, votes for intervals. Data from his lab, he says, show that even a few minutes per week of high-intensity intervals can “increase VO2 max to the same extent” as many hours per week of more moderate, prolonged endurance training.
Other scientists have found that intervals can elicit even greater increases in VO2 max than longer, slower workouts, if the total energy output is the same. This means that, per minute, you get more physiological bang from intervals, an important consideration if your exercise time is limited. ‘‘Of course,’’ Dr. Gibala adds, ‘‘it is probably most effective’’ to deploy both intervals and traditional longer workouts.