Anaerobic Threshold and Why It Is Important?

By Dan Carey, Phd., Health & Human Performance, Univ. of St. Thomas

[this is the third in a series of posts that will look at BMR, VO2 max, and measuring anaerobic threshold]


Most people think the anaerobic threshold is that point in a progressive test when the body switches from aerobic to anaerobic threshold. This is incorrect. The anaerobic threshold is that point in the test where anaerobic metabolism begins to contribute to aerobic metabolism.

This level is important to know because it is the highest level of exertion that could be maintained over a prolonged period. Dr. David Costill demonstrated back in the 1970’s that endurance athletes will self-select the pace at anaerobic threshold when performing races of one hour or longer. They intuitively know that a faster pace will result in the use of anaerobic metabolism, the build-up of lactic acid (although this theory is currently under scrutiny) and early fatigue.

In highly competitive endurance athletes, the anaerobic threshold oxygen consumption is a better predictor of performance than VO2 max. Frank Shorter won the Olympic marathon with one of the lowest VO2 max values among the competitors. He won because he had an extremely high anaerobic threshold VO2. He could maintain above 90% of his VO2 max for the entire race!!

The importance of the anaerobic threshold to performance is further illustrated by the fact that, while VO2 max peaks at about age 25 for elite distance runners, performance continues to get better for another 10-15 years. This is because training continues to increase the anaerobic threshold.