What is VO2 Max?

In basic terms, VO₂ max is an indicator of aerobic endurance and cardiovascular fitness. It is a measure of maximal oxygen consumption. It is also termed peak oxygen uptake or maximal oxygen capacity. VO₂ max is a measure of the cardiovascular system’s ability to deliver oxygen to the working muscles.

It is interesting to note that the working muscles are the limiting factor when it comes to oxygen consumption, rather than circulatory delivery of oxygen in the blood (1). Therefore, when our VO₂ max increases, our oxygen delivery increases, but more importantly the muscles become more efficient at utilizing oxygen that is delivered via the bloodstream.

VO₂ max is the maximum amount of oxygen in milliliters an individual can use in one minute per kilogram of body weight (VO₂ max = ml/min/kg). Therefore, VO₂ max is relative to that individual. VO₂ max can be measured directly by a mask that measures gas concentrations in expired air. This is measured while completing gradual incremental exercise tests (many versions exist). This type of testing is usually expensive and requires a great deal of equipment.

Additionally, VO₂ max can be measured indirectly using max heart rate and work rate values. This is a cheaper and more accessible alternative, however, it is a less accurate test of a true VO₂ max.

VO₂ max can be a useful indicator of fitness and endurance capacity. A low VO₂ max will indicate a low level of fitness and vice versa. However, high level endurance athletes VO₂ max levels may slightly vary from one another, and researchers believe there are other factors that come in to play when determining endurance performance results (2). Therefore, VO₂ max is not an exact performance predictor, but a useful guide to see where your fitness level falls for your age and gender.

VO₂ max can be improved by steady-state regular exercise but can also be increased by high intensity interval training as well (2). So if you don’t have enough time to do a long bike or run, there are other time saving alternatives to improve VO₂ max results and ultimately improve your endurance capacity.

While VO₂ max values are valuable information, individuals should also be aware of other important health and fitness indicators as well. Waist circumference, blood pressure, body composition, blood glucose levels, and even strength levels are all important indicators of fitness.

1. Human cardiovascular adjustments to exercise and thermal stress. Loring B Rowel. Physiological Reviews. 1974.
2. Effect of high intensity interval training on cardiovascular function, VO₂ max, and muscular force. Todd A. Astorino et al. Journal of Strength and Conditioning Research. 2012.