Vo2 Max refers to the maximal oxygen uptake and is expressed in millilitres per kilogram of body weight per minute (ml.kg.min). It is the essential tool for determining a persons energy expenditure at any given effort level.
This means when you know a persons Vo2 Max and you know what to do with it, you can determine a whole range of values such as calories burned, fitness level, speed and distance ability, MET capabilities and so on.
Put another way, it is essentially the size of the engine! Vo2 refers to volume of oxygen uptake. Vo2 Maximum therefore refers to the maximum capability in volume of oxygen consumed by the body each minute during exercise, while breathing air at sea level.
Because oxygen consumption is linearly related to energy expenditure and heart rate, when we measure oxygen consumption, we are indirectly measuring an individual's capacity to do work aerobically.
Every cell consumes oxygen in order to convert food energy to usable ATP for cellular work (cellular metabolism). Muscle cells that are contracting have high demands for ATP. So it follows that active muscle cells consume more oxygen during exercise.
To receive this oxygen and use it to make ATP for muscle contraction, our muscle fibers are absolutely dependent on 2 things:
- An external delivery system to deliver oxygen from the atmosphere to the working muscle cells.
- Mitochondria to carry out the process of aerobic energy transfer.
We need a strong and efficient heart to deliver oxygen rich blood to the muscles, and we need mitochondria-rich muscles to use the oxygen and support high rates of exercise.
VO2 max values (ml/kg/min) for selected groups and individuals are as follows:
- General Population, Female, Aged 20-29: 35-43
- General Population, Male, Aged 20-29: 44-51
- US College Track, Male: 57.4
- College Students, Male: 44.6
- Highest Recorded Female (World-Class Marathoner): 74
- Highest Recorded Male (Cross-Country Skier): 94
To find out the various protocols for predicting/measuring a persons Vo2 Max and how to use it to determine metabolic function check out the Vo2 Expert Online Course from Metabolic Training Expert).