VO2 Max is your body’s maximal oxygen uptake ability. This means the upper limit of how much oxygen your body can absorb during aerobic exercise. It is measured in millilitres of oxygen per kilogram of body mass per minute.
The VO2 Max score is a good indicator of endurance and aerobic performance, and is useful for tracking progress over time.
VO2 max (also maximal oxygen consumption, maximal oxygen uptake, peak oxygen uptake or maximal aerobic capacity) is the maximum rate of oxygen consumption as measured during incremental exercise, most typically on a motorized treadmill. Maximal oxygen consumption reflects the aerobic physical fitness of the individual, and is an important determinant of their endurance capacity.
VO2 max is expressed either as an absolute rate in (for example) Litre of oxygen per minute (L/min) or as a relative rate in (for example) millilitres of oxygen per kilogram of body per minute (e.g., mL/(kg·min)). The latter expression is often used to compare the performance of endurance sports athletes. However, VO2 max generally does not vary linearly with body mass, either among individuals, so comparisons of the performance capacities of individuals that differ in body size must be done with appropriate statistical procedures.
Accurately measuring VO2 max involves a physical effort sufficient in duration and intensity to fully tax the aerobic energy system. Clinical and athletic testing usually involves a graded exercise test (either on a treadmill or on a cycle ergometer in which exercise intensity is progressively increased while measuring:
- ventilation and
- oxygen and carbon dioxide concentration of the inhaled and exhaled air.
VO2 max is reached when oxygen consumption remains at a steady state despite an increase in workload.
The average untrained healthy male will have a VO2 max of approximately 35–40 mL/(kg·min). The average untrained healthy female will score a VO2 max of approximately 27–31 mL/(kg·min). These scores can improve with training and decrease with age, though the degree of trainability also varies very widely: conditioning may double VO2 max in some individuals, and will never improve it in others. In one study, 10% of participants showed no benefit after completing a 20-week conditioning program, although the other 90% of the test subjects all showed substantial improvements in fitness to varying degree.
In sports where endurance is an important component in performance, such as cycling, rowing, cross-country skiing, swimming and running, world-class athletes typically have high VO2 maxima. Elite male runners can consume up to 85 mL/(kg·min), and female elite runners can consume about 77 mL/(kg·min).Five time Tour de France winner Miguel Indurain is reported to have had a VO2 max of 88.0 at his peak, while cross-country skier Bjørn Dæhlie measured at 96 mL/(kg·min). Dæhlie’s result was achieved out of season, and physiologist Erlend Hem who was responsible for the testing stated that he would not discount the possibility of the skier passing 100 mL/(kg·min) at his absolute peak.
Factors affecting VO2 max
The factors affecting VO2 are often divided into supply and demand. Supply is the transport of oxygen from the lungs to the mitochondria (including lung diffusion, stroke volume, blood volume, and capillary density of the skeletal muscle) while demand is the rate at which the mitochondria can reduce oxygen in the process of oxidative phosphorylation. Of these, the supply factor is often considered to be the limiting one. However, it has also been argued that while trained subjects probably are supply limited, untrained subjects can indeed have a demand limitation.