No doubt you’ve heard about it or maybe even had it tested as part of that Exercise Phys grad student study you volunteered for at university. Perhaps you’ve noticed it as an available metric on your Garmin watch? A number of smart watches now purport to provide a close estimate to your VO2max. But what is it exactly and how is it measured?
VO2 max is the maximum volume of oxygen that can be used by your body during exercise. It is measured in millilitres of oxygen per kilogram of bodyweight per minute. Although it provides a key measure of endurance ability, the number alone is not a reliable performance indicator and VO2 max values may vary considerably even amongst elite athletes with similar performances. Intensive training can result in modest improvements in VO2 max but the highest values found amongst athletes are largely down to genetics.
While many devices attempt to estimate your VO2, accurate measurement requires wearing a breathing mask to measure the oxygen you breathe in and the carbon dioxide you breathe out while running progressively harder on a treadmill. For example, if you were to run on a treadmill that got faster over a period of 7 to 11 minutes to a point where you can’t breathe harder and faster, this fixed point is your VO2 max.
Application of VO2 max in training.
It is uncomfortable running at or close to our VO2 max and many runners dread such interval training. Learning to tolerate such intensities increases our pain tolerance and readies us for the same discomfort in shorter races. Well-trained athletes typically see little or no change in their VO2 max training at such intensities, but they do benefit in terms of run performance, run economy and strength. Longer term benefits include slowing the decline in our VO2max as we age. *
When doing intervals, it takes about a minute to reach the range of oxygen consumption corresponding to our VO2max, so on shorter intervals we spend less time in this zone. If the intervals are too long you will not be able to sustain the optimal intensity for the entire workout. The length of rest between intervals will also determine how quickly it takes to reach VO2 max and the best coaches will optimise the length of these rests to maximise your time in this zone and still complete the planned workout. Interval lengths are typically 2 to 6 minutes. They should be executed at an effort of hard or roughly 3km pace for most Harriers.
Key points
- The primary benefits of VO2 max training include better run performance, run economy and a slowing of the natural decline of VO2 max as we age.
- Your tolerance to the discomfort of VO2 max training will increase with training.
- Strict adherence to both the length of the intervals and rests in a planned workout will ensure you spend the greatest amount of time at VO2 max.
*Gries et al. Cardiovascular and skeletal muscle health with lifelong exercise. J Appl Physiol. 125: 1636-1645, 2018.