VO2 max

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VO ₂ max (also maximal oxygen consumption , maximal oxygen uptake , peak oxygen uptake or maximum aerobic capacity ) is the maximum level of oxygen consumption measured during additional exercise (increased intensity exercise). This name is derived from V - volume, O ₂ - oxygen, max - maximum. Maximum oxygen consumption reflects the individual's cardiorespiratory fitness and is an important determinant of their endurance capacity during prolonged exercise.

Video VO2 max

Health

VO ₂ max is widely used as a health indicator. In 2016, the American Heart Association published a scientific statement recommending that cardiorespiratory fitness (CRF), can be calculated as VO ₂ max, regularly assessed and used as a clinical vital sign. This statement is based on increasing evidence that lower levels of fitness are associated with a higher risk of cardiovascular disease, all-cause mortality, and mortality rates that come from different types of cancer. In addition to risk assessment, the AHA recommendations mention the value of fitness measures to validate prescribed exercise, physical activity counseling, and improve both patient management and patient health.

Maps VO2 max

Expression

VO ₂ max is expressed as the absolute level in (eg) liters of oxygen per minute (L/min) or as relative (eg) milliliters of oxygen per kilogram of body mass per minute (eg, mL/(kg, Â ± mnt)). The latter expression is often used to compare the performance of endurance sport athletes. However, VO ₂ max generally does not vary linearly with body mass, either among individuals within a species or among species, so the comparative capacity capacity of individuals or different species in body size should be performed by statistical procedures as appropriate, such as covariance analysis.

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Measurement

VO measurements accurately ₂ involve considerable physical effort in duration and intensity to fully overload the aerobic energy system. In general clinical and athletic trials, this usually involves a graded exercise test (either on the treadmill or on the ergometer cycle) where the intensity of the exercise increases when measuring:

• vent and
• the concentration of oxygen and carbon dioxide from the air being inhaled and exhaled.

VO ₂ max is reached when oxygen consumption remains steady despite the increase in workload.

Fick's Equation

VO ₂ maks ditentukan dengan benar oleh persamaan Fick:

${\ displaystyle \ mathrm {VO_ {2} \; max} = Q \ times \ (\ mathrm {C_ {a} O_ {2}} - \ mathrm {C_ { v} O_ {2}})}  ÂÂ$ , ketika nilai-nilai ini diperoleh selama pengerahan tenaga pada upaya maksimal.

di mana Q adalah output jantung jantung, C _a O ₂ adalah kandungan oksigen arteri, dan C < sub> v O ₂ adalah konten oksigen vena.

(C _a O ₂ - C _v O ₂ ) juga dikenal sebagai perbedaan oksigen arteriovenous.

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Estimasi

VO ₂ measurement tests may be harmful to individuals who are not considered normal healthy subjects, as any problems with the respiratory and cardiovascular systems will be greatly aggravated in clinically ill patients. Thus, many protocols for estimating VO ₂ max have been developed for those who test traditional VO ₂ would be too risky. This is generally similar to the max test VO ₂ , but does not reach the maximum of the respiratory and cardiovascular systems and is called the sub-maximal test.

Uth-SÃÆ'¸rensen-Overgaard-Pedersen estimation

Perkiraan lain dari VO ₂ max, berdasarkan denyut jantung maksimum dan istirahat, diciptakan oleh sekelompok peneliti dari Denmark. Ini diberikan oleh:

${\ displaystyle {\ text {V}} {\ ce {O2}} {\ text {max}} \ kira {\ frac {{\ text {HR}} _ {\ text {max}}} {{\ text {HR}} _ {\ text {rest}}}} \ times 15.3 {\ text {mL}}/({\ text {kg · menit}}).}  ÂÂ$

This equation uses maximum heart rate ratios (HR _max ) for resting heart rate (HR _break ) to predict VO ₂ max. The researchers caution that the conversion rule is based on measurements in trained men aged 21 to 51 alone, and may not be reliable when applied to other subgroups. They also suggest that this formula is most reliable when based on actual measurements of the maximum heart rate, rather than age-related estimates.

Cooper Test

Kenneth H. Cooper conducted research for the United States Air Force in the late 1960s. One of these results is the Cooper test where distance traveled within 12 minutes is measured. Based on measurable distance, the estimated VO ₂ max [in mL/(kgÃ, Â · min)] is:

${\ displaystyle \ mathrm {VO_ {2} \; max} \ approximately {d_ {12} -504.9 \ over 44.73}} Â Â$

where d ₁₂ is the distance (in meters) covered in 12 minutes

Persamaan alternatif adalah:

${\ displaystyle \ mathrm {VO_ {2} \; max} \ kira-kira {(35.97 * dmiles_ {12}) - 11.29}}  ÂÂ$

where dmiles ₁₂ is the distance (in miles) covered in 12 minutes,

Multi-stage fitness test

There are other reliable tests and a max VO ₂ calculator to estimate VO ₂ max, especially the multi-stage fitness test (or test beep ).

Rockport fitness walk

Estimated VO ₂ max of tracks over a mile with duration t, combining sex, age, pound weight (BW), and heart rate (HR) at the end of the mile. Factor x is 6,3150 for men, 0 for women. BW in lbs, time in minutes.

$Â\; ÂÂ\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â{\displaystyle Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\mathrm{V}Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â{\mathrm{O}}_{Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â2Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â}Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\mathrm{m}Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\mathrm{a}Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\mathrm{x}Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â?Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â132.853Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â-Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â0.0769Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂBÂ\; Â\; Â\; Â\; Â\; Â\; Â\; ÂWÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â-Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â0.3877Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\text{age}Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â-Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\mathrm{3,2649}Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂtÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â-Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â0.1565Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂHÂ\; Â\; Â\; Â\; Â\; Â\; Â\; ÂRÂ\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; ÂxÂ\; Â\; Â\; Â\; Â\; Â}Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\{\backslash \; displaystyle\; \backslash \; mathrm\; \{VO\_\; \{2\}\; \backslash ;\; max\}\; \backslash \; approx\; 132.853-0.0769BW-0.3877\; \{\backslash \; text\; \{age\}\}\; -\; 3.2649t-0.1565HR\; x\}\; Â\; Â$

Firstbeat method

The Firstbeat method of volume estimation VO ₂ , whose patent application was filed in 2012, is widely licensed and used in consumer technology applications. The first consumer fitness device using the Firstbeat method of volume estimation VO ₂ is Garmin Forerunner 620, released in 2013. Since then, Suunto, Jabra, Huawei, and PulseOn have also introduced products that utilize Firstbeat method.

This method relies on an analysis of the linear relationship between oxygen consumption and running speed, which means that the running oxygen cost increases as the running speed increases. To facilitate analysis and improve accuracy, the time segments of recorded activity data are identified by heart rate range and reliability; and only the most reliable segments are used. This enables the method to be applied for free running, walking and cycling activities and reduces the need for specialized fitness testing protocols. This calculation requires the user's basic anthropometric data (age, gender, height, weight, etc.), Heart rate data (internal workload), and external workload size.

• External workload runs/runs: Movement speeds obtained either from GPS sensors or accelerometers
• Cycling the external workload: the power output is expressed in watts and measured with a power meter.

The VO ₂ estimate provided by the Firstbeat method is most accurate during running activities that utilize GPS to capture external workload data. This combination has been validated to 95% accurate compared to laboratory testing. Since the Firstbeat estimation method is sub-optimal, the estimation accuracy is closely related to the validity of the HRmax value used in the calculations.

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Level

Healthy untrained males on average will have a max VO ₂ of about 35-40 mL/(kgÃ, Â ± mnt). An untrained healthy woman on average will get a VO ₂ max of about 27-31 mL/(kgÃ, Â ± mnt). This score can be improved by training and decreases with age, although the level of ability also varies greatly: conditioning can double VO ₂ max on some individuals, and will never fix it on others. In one study, 10% of participants showed no benefit after completing the 20-week conditioning program, although the other 90% of the test subjects all showed a substantial increase in fitness for many levels.

In sports where endurance is an important component of performance, such as cycling, rowing, cross-country skiing, swimming and running, world class athletes usually have a high VO ₂ maxima. Elite male runners can consume up to 85 mL/(kgÃ,  ° mnt), and female elite runners can consume about 77Ã, mL/(kgÃ,min). Five-time Tour de France winner Miguel Indurain reportedly has a VO ₂ max of 88.0 at the peak, while cross-country skier BjÃÆ'¸rn DÃÆ'Â|hlie measured at 96Ã, mL/(kgÃ,  · mnt). The DÃÆ'Â|hlie result was achieved off-season, and the physiologist Erlend Hem who was in charge of testing stated that he would not reduce the possibility of skiers passing 100Ã, mL/(kgÃ,  · min) at the absolute peak. The Norwegian cyclist Oskar Svendsen is estimated to have recorded the highest VO ₂ max 97,5Ã, mL/(kgÃ,  · min), when aged 18.

The highest value in absolute terms for humans is often found among rowers, as their much larger numbers yield a slightly lower VO ₂ per kg. The elite oarsman measured in 1984 has a max value of VO ₂ 6.1 Ã,  ± 0.6Ã, L/min and oars 4.1Ã,  ± 0.4Ã, L/min. The rowers are attracted to the absolute value of VO ₂ max and lung capacity, and the fact that they are measured in the same unit means both are often confused. The British Rower Sir Matthew Pinsent was reported to have VO ₂ 7.5Ã, L/min or 8.5Ã, L/min, although the latter may be confusion with a lung capacity of 8.5 liters. New Zealand Sculler Rob Waddell has one of the highest absolute absolute VO2 levels ever tested.

Values ​​have been measured in several other animal species: the dried horses have a VO ₂ max of about 180 mL/(kgÃ, Â ± mnt). The Siberian dog that ran on the Iditarod Dog Sled Race Competition has a max value of VO ₂ as high as 240Ã, mL/(kgÃ, Â ± mnt).

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Limiting factor

Factors that affect VO ₂ are often divided into inventory 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 skeletal muscle) while demand is the rate at which mitochondria can reduce oxygen in the oxidative phosphorylation process. Of these, supply factors are often perceived as limiting. However, it has also been argued that although trained subjects may be limited inventory, untrained subjects may indeed have a demand restriction.

Tim Noakes, a sports and sports professor at the University of Cape Town, explains a number of factors that can affect VO ₂ max: age, gender, fitness and training, altitude changes, and ventilatory muscle actions. Noakes also asserts that VO ₂ max is a relatively poor performance predictor of runners due to variations in economic run and fatigue resistance during prolonged exercise.

Cardiac output, pulmonary diffusion capacity, oxygen-carrying capacity, and other peripheral limitations such as muscle diffusion capacity, mitochondrial enzymes, and capillary density are examples of determinants of VO ₂ max. The body functions as a system. If any of these factors are sub-par, then the entire system loses its normal capacity to function properly.

The drug erythropoietin (EPO) can increase VO ₂ max by a significant amount in humans and other mammals. This makes EPO attractive to athletes in endurance sports, such as professional cycling. The EPO has been banned since the 1990s as a prohibited substance of performance improvement. But in 1998 it became widespread in cycling and caused Festina affairs and was mentioned everywhere in the USADA 2012 report on the US Postal team. Greg LeMond has suggested to create a baseline for the VO 'sub (2) max riders (and other attributes) to detect abnormal performance improvements.

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See also

• Anaerobic exercises
• Open arterial oxygen difference
• Cardiorespiratory Fitness
• Comparative physiology
• VDOT
• Oxygen pulse
• Respirometry
• Training effect
• vVO ₂ max
• Running economy

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References

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External links

• VO ₂ max Calculator - Rockport Street Test
• So What's VO2 exactly?
• Value by age, mL/(kgÃ, Â ° mnt)

Source of the article : Wikipedia