VO2 max

# Overview
VO2 max is the maximum capacity to transport and utilize oxygen during incremental exercise. (The derivation is V - volume per time, O2 - oxygen, max - maximum). It is also called maximal oxygen consumption or maximal oxygen uptake. It is also known as aerobic capacity, which reflects the physical fitness of a person.
It is the maximal intake of oxygen that a person can take in at the moment of exhaustion, which is determined according to that person's age, height, weight, fitness level and basal metabolic rate.
Expressed either as an absolute rate in litres of oxygen per minute (l/min) or as a relative rate in millilitres of oxygen per kilogram of bodyweight per minute (ml/kg/min), the latter expression is often used to compare the performance of endurance sports athletes. A less size-biased measure is to divide by \sqrt{mass^2} rather than mass.
It has become a standard testing method for athletes, athletic and sportive people and even for airplane pilots, car race drivers, and individuals with jobs demanding them to be fit, in good shape and health. It is a part of cardiac and pulmonary screenings too.

# Measuring VO2 max
Accurately measuring VO2 max involves a physical effort sufficient in duration and intensity to fully tax the aerobic energy system. In general clinical and athletic testing, this 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 steady state despite an increase in workload.

## Fick Equation
VO2 max is properly defined by the Fick Equation:
where Q is the cardiac output of the heart, CaO2 is the arterial oxygen content, and CvO2 is the venous oxygen content.

## Cooper test
Dr. Kenneth H. Cooper conducted a study for the United States Air Force in the late 1960s. One of the results of this was the Cooper test in which the distance covered running in 12 minutes is measured. An approximate estimate for VO2 max (in ml/min/kg) is:
where d12 is distance (in metres) covered in 12 minutes.
There are several other reliable tests and VO2 max calculators to estimate VO2 max.

# VO2 max Levels
VO2 max varies considerably in the population. The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/min/kg. The average young untrained female will score a VO2 max of approximately 2.0 litres/minute and 38 ml/min/kg. These scores can improve with training and decrease with age, though the degree of trainability also varies very widely.
In sports where endurance is an important component in performance, such as cycling, rowing, cross-country skiing and running, world class athletes typically have high VO2 maximums.  World class male athletes, cyclists and cross-country skiers typically exceed 80 ml/kg/min and a rare few may exceed 90 ml/kg/min for men and 70 ml/kg/min for women. Three time Tour de France winner Greg LeMond is reported to have had a VO2 max of 92.5 at his peak - one of the highest ever recorded, while cross-country skier Bjrn Dhlie measured at an astounding 96 ml/kg/min. It should also be noted that Dhlie's result was achieved out of season and that 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. By comparison a competitive club athlete might achieve a VO2 max of around 70 ml/kg/min. World class rowers are physically very large endurance athletes and typically do not score as high on a per weight basis, but often score exceptionally high in absolute terms. Male rowers typically score VO2 maximums over 6 litres/minute, and some exceptional individuals have exceeded 8 l/min.
To put this into perspective, thoroughbred horses have a VO2 max of around 180 ml/min/kg. Siberian dogs running in the Iditarod Trail Sled Dog Race sled race have VO2 values as high as 240 ml/min/kg.