Exercise Testing Part I... VO2max

Earlier this month I underwent some graded exercise testing at Duke University.  The objective was to find my (run) VO2max, lactate threshold, and max heart rate.  VO2max is a measure of aerobic capacity.  Also referred to as maximal oxygen consumption, VO2max is a test of cardiovascular fitness.  In practical terms, your VO2max represents the highest level of 'work' your body can function at for any length of time.  From a well executed VO2max test This is expressed in milliliters of oxygen consumed per kilogram of body weight per minute (ml/kg/min).  A person's VO2max is found during a graded exercise (in my case, treadmill) test in which exhaled levels of oxygen and carbon dioxide are measured while exercise intensity increases every few minutes until exhaustion.  You may have seen this test depicted before on TV.  A Gatorade commercial comes to mind for me, a person running at near max effort wearing a mask with tubing from a mouthpiece leading to a computer that analyzes the runners expired gases.

The physiologic characteristics that come together to make up a person's VO2max are largely genetic.  Heart size, heart rate, stroke volume (amount of blood pumped with each beat/stroke), muscle fiber composition are some of the more rigid physiological influences of VO2max.  This is not to say that your VO2max can't be increased through training.  Fitness level, muscle capillary/mitochondrial density, and optimal power to body weight ratio (losing excess body fat) are all responses to training that can have a positive impact on your VO2max.  Think of this in terms of exercise efficiency.  As your body adapts and becomes increasingly fit as a response to aerobic training, many of the physiologic characteristics listed above fine tune themselves, making you a more efficient aerobic machine.  This in turn can have a positive impact on your maximal aerobic working capacity (VO2max). 


VO2max is a great indicator of a person's endurance capacity, but not the best indicator of training efficiency or race performance.  (A better indicator of predicted race performance is lactate threshold, which will be discussed in my next post.)  Generally speaking, the more aerobically fit you are, the higher your tested VO2max should be.  That being said, there are documented cases of world class male distance runners with VO2max values hovering around 60 ml/kg/min, and multiple instances of local 10k weekend warriors that have tested in the 75+ mil/kg/min range.  Steve Prefontaine (American distance runner) had a tested VO2max of 84.4 mil/kg/min.  American cyclist Lance Armstrong has tested at 83.8 mil/kg/min.  Norwegian cross country skier Espen Harald Bjerke holds the distinction of having the highest VO2max ever recorded...96.0 mil/kg/min!  If you were wondering, I tested at 70.0 mil/kg/min.  Hardly a Norwegian X-country skier.


Here you can find some age graded VO2max reference norms for men and women.  Check back soon, my next post will deal with lactate threshold/max heart rate values and how they relate to training.  Thanks for reading.


jw