VO2 max
Encyclopedia
VO2 max is the maximum capacity of an individual's body to transport and use oxygen during incremental exercise
, which reflects the physical fitness
of the individual. The name is derived from V - volume
, O2 - oxygen
, max - maximum.
VO2 max is expressed either as an absolute rate in litre
s 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.
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.
:
, when these values are obtained during an exertion at a maximal effort.
This equation uses maximum heart rate (HRmax) and resting heart rate (HRrest) to estimate VO2 max in ml/min/kg.
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. Based on the measured distance, an estimate of 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, most notably the multi-stage fitness test
(or bleep test), based on the research paper by Leger and Lambert, "A Maximal Multi-Stage 20m Shuttle Run Test to predict VO2 Max".
The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/kg/min. The average young untrained female will score a VO2 max of approximately 2.0 litres/minute and 38 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 VO2max in some individuals, and will never improve at all in others.
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 maximums. Elite male runners can generate up to 85 ml/kg/min, and female elite runners can generate 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. 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/kg/min. Siberian dogs running in the Iditarod Trail Sled Dog Race have VO2 values as high as 240 ml/kg/min.
. 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.
Tim Noakes, a professor of exercise and sports science at the University of Cape Town
, describes a number of variables that may affect VO2 max: age
, gender
, fitness and training, changes in altitude
, and action of the ventilatory muscles. Noakes also asserts that VO2 max is a relatively poor predictor of performance in runners due to variations in running economy
and fatigue resistance during prolonged exercise.
Needless to say, cardiac output, pulmonary diffusion capacity, oxygen carrying capacity, and other peripheral limitations like muscle diffusion capacity, mitochondrial enzymes, and capillary density are all examples of VO2 max determinants. The body works as a "system". If one of these factor is sub-par, then the whole system loses its normal capacity to function properly.
Incremental exercise
Incremental exercise is exercise that increases in intensity over time.Incremental exercise is often used during fitness tests such as the YMCA submaximal test....
, which reflects the physical fitness
Physical fitness
Physical fitness comprises two related concepts: general fitness , and specific fitness...
of the individual. The name is derived from V - volume
Volume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
, O2 - oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, max - maximum.
VO2 max is expressed either as an absolute rate in litre
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
s of oxygen per minute (l/min) or as a relative rate in millilitres of oxygen per kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
of bodyweight per minute (ml/kg/min). The latter expression is often used to compare the performance of endurance sports athletes.
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 treadmillTreadmill
A treadmill is an exercise machine for running or walking while staying in one place. The word treadmill traditionally refers to a type of mill which was operated by a person or animal treading steps of a wheel to grind grain...
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 equationFick principle
Developed by Adolf Eugen Fick , the Fick principle was first devised as a technique for measuring cardiac output. However, its underlying principles may be applied in a variety of clinical situations....
:
, when these values are obtained during an exertion at a maximal effort.-
- where Q is the cardiac outputCardiac outputCardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
of the heart, CaO2 is the arterial oxygen content, and CvO2 is the venous oxygen content.
- where Q is the cardiac output
-
- (CaO2 – CvO2) is also known as the arteriovenous oxygen differenceArteriovenous oxygen differenceThe arteriovenous oxygen difference, or a-vO2 diff, is the difference in the oxygen content of the blood between the arterial blood and the venous blood. It is an indication of how much oxygen is removed from the blood in capillaries as the blood circulates in the body...
.
- (CaO2 – CvO2) is also known as the arteriovenous oxygen difference
Estimation of VO2 max
Tests measuring VO2 max can be dangerous in individuals who are not considered normal healthy subjects, as any problems with the respiratory and cardiovascular systems will be greatly exacerbated in clinically ill patients. Thus, many protocols for estimating VO2 max have been developed for those for whom a traditional VO2 max test would be too risky. These generally are similar to a VO2 max test, but do not reach the maximum of the respiratory and cardiovascular systems and are called sub-maximal tests.Uth—Sørensen—Overgaard—Pedersen estimation
Another estimate of VO2 max, based on maximum and resting heart rates, was created by a group of researchers from Denmark. It is given by:This equation uses maximum heart rate (HRmax) and resting heart rate (HRrest) to estimate VO2 max in ml/min/kg.
Cooper test
Kenneth H. CooperKenneth H. Cooper
Kenneth H. Cooper is an doctor of medicine and former Air Force Colonel from Oklahoma, who introduced the concept of aerobics. He is the author of the 1968 book Aerobics, which emphasized a point system for improving the cardiovascular system...
conducted a study for the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
in the late 1960s. One of the results of this was the Cooper test
Cooper test
The Cooper test is a test of physical fitness. It was designed by Kenneth H. Cooper in 1968 for US military use. In the original form, the point of the test is to run as far as possible within 12 minutes...
in which the distance covered running in 12 minutes is measured. Based on the measured distance, an estimate of 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, most notably the multi-stage fitness test
Multi-stage fitness test
The multi-stage fitness test, also known as the bleep test, beep test, pacer test, Leger-test or 20-m shuttle run test, is used by sports coaches and trainers to estimate an athlete's VO2 max...
(or bleep test), based on the research paper by Leger and Lambert, "A Maximal Multi-Stage 20m Shuttle Run Test to predict VO2 Max".
VO2 max levels
“Maximal oxygen uptake (VO2max) is widely accepted as the single best measure of cardiovascular fitness and maximal aerobic power. Absolute values of VO2max are typically 40-60% higher in men than in women.”The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/kg/min. The average young untrained female will score a VO2 max of approximately 2.0 litres/minute and 38 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 VO2max in some individuals, and will never improve at all in others.
In sports where endurance is an important component in performance, such as cycling
Cycling
Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, or for sport. Persons engaged in cycling are cyclists or bicyclists...
, rowing
Sport rowing
Rowing is a sport in which athletes race against each other on rivers, on lakes or on the ocean, depending upon the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades as they are pushed against the water...
, cross-country skiing
Cross-country skiing
Cross-country skiing is a winter sport in which participants propel themselves across snow-covered terrain using skis and poles...
, swimming
Swimming (sport)
Swimming is a sport governed by the Fédération Internationale de Natation .-History: Competitive swimming in Europe began around 1800 BCE, mostly in the form of the freestyle. In 1873 Steve Bowyer introduced the trudgen to Western swimming competitions, after copying the front crawl used by Native...
and running
Running
Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground...
, world class athletes typically have high VO2 maximums. Elite male runners can generate up to 85 ml/kg/min, and female elite runners can generate about 77 ml/kg/min . Five time Tour de France
Tour de France
The Tour de France is an annual bicycle race held in France and nearby countries. First staged in 1903, the race covers more than and lasts three weeks. As the best known and most prestigious of cycling's three "Grand Tours", the Tour de France attracts riders and teams from around the world. The...
winner Miguel Indurain
Miguel Indurain
Miguel Ángel Indurain Larraya is a retired Spanish road racing cyclist. He won five consecutive Tour de Frances from 1991 and 1995, the first to do so, and the fourth athlete to win five times. He won the Giro d'Italia twice, becoming one of only seven people in history to achieve the Giro Tour...
is reported to have had a VO2 max of 88.0 at his peak, while cross-country skier Bjørn Dæhlie
Bjørn Dæhlie
Bjørn Erlend Dæhlie is a Norwegian businessman and retired cross-country skier. With 8 olympic gold medals, Dæhlie is the most winning winter olympic champion of all time. With nine gold medals in the Nord World Ski Championships he is in addition the most winning World Champion skier...
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. 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/kg/min. Siberian dogs running in the Iditarod Trail Sled Dog Race have VO2 values as high as 240 ml/kg/min.
Factors affecting VO2 max
The factors affecting VO2 are often divided into supply and demand factors. 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 phosphorylationOxidative phosphorylation
Oxidative phosphorylation is a metabolic pathway that uses energy released by the oxidation of nutrients to produce adenosine triphosphate . Although the many forms of life on earth use a range of different nutrients, almost all aerobic organisms carry out oxidative phosphorylation to produce ATP,...
. 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.
Tim Noakes, a professor of exercise and sports science at the University of Cape Town
University of Cape Town
The University of Cape Town is a public research university located in Cape Town in the Western Cape province of South Africa. UCT was founded in 1829 as the South African College, and is the oldest university in South Africa and the second oldest extant university in Africa.-History:The roots of...
, describes a number of variables that may affect VO2 max: age
Age
Age may refer to:* Age , an aspect of mathematical model theory* Age , an international peer-reviewed journal operated by Springer.* The Age, a daily newspaper published in Melbourne, Australia* Agé, a god* Åge, a given name...
, gender
Gender
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. Depending on the context, the discriminating characteristics vary from sex to social role to gender identity...
, fitness and training, changes in altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
, and action of the ventilatory muscles. Noakes also asserts that VO2 max is a relatively poor predictor of performance in runners due to variations in running economy
Running economy
Running economy is a measure of how efficiently a person uses oxygen while running at a given pace. Expressed as the rate of oxygen consumption per distance covered , running economy is the energy required running submaximally at a given velocity. Those who are able to consume less oxygen while...
and fatigue resistance during prolonged exercise.
Needless to say, cardiac output, pulmonary diffusion capacity, oxygen carrying capacity, and other peripheral limitations like muscle diffusion capacity, mitochondrial enzymes, and capillary density are all examples of VO2 max determinants. The body works as a "system". If one of these factor is sub-par, then the whole system loses its normal capacity to function properly.
See also
- Anaerobic exerciseAnaerobic exerciseAnaerobic exercise is exercise intense enough to trigger anaerobic metabolism. It is used by athletes in non-endurance sports to promote strength, speed and power and by body builders to build muscle mass...
- Arteriovenous oxygen differenceArteriovenous oxygen differenceThe arteriovenous oxygen difference, or a-vO2 diff, is the difference in the oxygen content of the blood between the arterial blood and the venous blood. It is an indication of how much oxygen is removed from the blood in capillaries as the blood circulates in the body...
- Cardiorespiratory fitnessCardiorespiratory fitnessCardiorespiratory fitness refers to the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity...
- RespirometryRespirometryRespirometry is a general term that encompass a number of techniques for obtaining estimates of the rates of metabolism of vertebrates, invertebrates, plants, tissues, cells, or microorganisms via an indirect measure of heat production ....
- Training effectTraining effectTraining effect refers to specific changes in muscular, cardiovascular, and neurohumoral systems that lead to improvement in functional capacity and strength due to regular endurance or resistance training. It has also been defined as "an elevation of metabolism produced by exercise".Kenneth H...
- VDOT
- vVO2maxVVO2MaxvVO2max is an intense running pace which can be maintained for only about six minutes. This is the minimum speed for which the organism's maximal oxygen uptake is reached ; at higher paces, additional power is entirely delivered by anaerobic processes...