VO2 Myth

“VO2 max” is an often discussed topic, particularly in terms of training, and an athlete’s capacity for performance.  It is a very important attribute. However, it seems to me it’s widely misunderstood when comes to establishing training objectives.  You’ve probably heard an athlete somewhere say something like, “I’m going to do VO2 max intervals tomorrow.” Or even, “I want to improve my VO2 max…” There is even a “VO2 max Zone” in many coaches’ Zone Training protocol.  The typical misconception is that it is a highly trainable physiological trait.

In fact, it generally is not. It is the most immutable of the three physiological attributes endurance athletes are concerned about. Can it be improved, especially from an untrained, or de-trained starting point? Yes, of course, and certainly it should be.  However, there is a low ceiling on improving this particular trait, and that’s mostly set by your parents (Yes, genetics largely determines “VO2 max”.)  So, of course you should be really careful when deciding on parents.  Regardless, trying really hard to alter your largely genetically predetermined “VO2 max” is sort of like trying to get taller.

Attributes that arehighly trainable, and should probably get the lion’s share of attention in training are (“lactate”)Threshold Levels(even though lactate – i.e. lactic acid – is only a very indirect measure of this phenomenon), and Economy (aka, efficiency or skills).  [Lactate, or “lactic acid,” is associated with acute muscle acidosis, which is believed to be accounted for by an accumulation of hydrogen ions, a by-product of metabolic activity, which increase very rapidly at increasingly higher workout intensities.]

Another misconception of VO2 max is that it’s all about your cardio-respiratory system.  It’s really more about muscles, i.e. capillary size and density in your muscles. (Capillaries are the site of O2/CO2 exchange in the working muscles.)  The more O2 your capillaries can delivery for use to working muscles, the more work (metabolic energy production) your muscles are able to perform.  Your lungs and heart are usually pretty good at delivering oxygenated blood there, and returning CO2 enriched blood (and hydrogen ions), to the heart and lungs to be re-oxygenated and/or breathed off.

“VO2 max,” in theory, measures the amount of oxygen that your body can utilize to perform physical work.  That’s it.  It has nothing directly to do with how fast you run, or how much weight you can lift, or how good are from the 3-point line.  It’s units are: Volume of O2 (liters) per Kg of body weigh per minute (L O2/Kg x Min).

So, what’s the take away?   Don’t spend a lot of time training for “VO2 max” effort, as a goal in itself. Rather, spend the time training forefficiencies at your specific level of intensity, needed for your next race.  That may include “VO2 max” efforts (e.g. 3 min run intervals at faster than 5K race pace effort), or it may not.  It may mean going for 5 hours on your bike at a moderate aerobic effort (IM athletes) which is nowhere near “VO2 max.”  If you train at high intensity and/or very high volume, your “VO2 max” will take care of itself.