Oxygen testing could maximize workouts

Fitness enthusiasts don’t really need an oxygen testing program to be fit, but the test can help tailor workouts to a specific fitness level.

Oxygen consumption testing, or VO2 max testing, has long been used to determine elite athletes’ cardiac fitness. It can be applied to everyone, says Conrad Earnest, director of the Center for Human Performance and Nutrition Research at the Cooper Institute in Dallas.

VO2 max is the maximum amount of oxygen, in milliliters, that a person can consume per minute per kilogram of body weight. The test measures heart rate and the ratio of carbon dioxide released to oxygen consumed. The higher your VO2 max, the more efficiently your body handles oxygen -- in other words, the fitter you are.

The test also yields the ideal heart rate zones for cardio training -- warm-up, aerobic, anaerobic and uber-tough intervals. A key number is your anaerobic threshold, the point at which your body shifts from burning mostly stored fats as fuel to using mainly glycogen, a sugar stored in muscle tissue. An exercise professional can use the anaerobic threshold and heart rate ranges to customize very efficient workouts.

Without a VO2 number, your heart rate monitor (or cardio machine) assumes a maximum heart rate based only on your age. This is often wrong by 30% or more.

But Earnest is concerned about health club VO2 testing. The tester, he says, needs a bachelor’s degree in exercise physiology and specialized training.