WhatIsSeries: VO2Max

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What is VO₂ and VO₂Max

VO₂ (or oxygen consumption) is a measure of the volume of oxygen that is used by your body to convert the energy from the food you eat into the energy molecules, called adenosine triphosphate (ATP), that your body uses at the cellular level. VO₂Max (or maximal oxygen consumption) is simply the maximum possible VO₂ that a given person can achieve. Therefore, by definition, a VO₂Max measurement is ultimately a measure of your cardiorespiratory fitness level. The V in VO₂ stands for volume, and in fact it is usually displayed in technical texts with a dot above it to indicate that it represents not just a volume, but a volume rate (i.e. a volume per unit of time). The O₂in VO₂ is the chemical formula for oxygen in its most stable form, the form that is found in the air we breathe. During aerobic/endurance exercise, as your exercise intensity increases, so does your VO₂. If you continue to increase your exercise intensity you will eventually reach a point of maximal exertion (i.e. you cannot work any harder than you already are). Your VO₂ at this stage of maximal exertion is called your maximal oxygen consumption (VO₂Max).

How is VO₂Max Measured?

VO₂ is essentially the difference between the amount of oxygen that a person inspires and the amount of oxygen that they expire. Therefore, to accurately determine someone’s VO₂ you need to know the volume of air that they inspire and expire and the percentage of oxygen in the inspired and expired air (remember, the percentage of oxygen in the inspired air is an already known constant, so you really only need to measure the percentage in the expired air).
Results for VO₂ measurements are generally displayed in L•min-1 (i.e. litres per minute, representing the volume of oxygen consumed by your entire body each minute) or, to account for differences in total body mass, in mL•kg-1•min-1 (i.e. millilitres per kilogram per minute, representing the volume of oxygen consumed each minute per kilogram of your body mass).

The method for measurement of VO₂ can be summarized according to the following equation

VO₂ = [VI x % O₂VI] – [VE x % O₂VE]

where [ VI = Volume of Inspired Air, % O₂VI = Percent Oxygen in Inspired Air , VE = Volume of Expired Air , % O₂VE = Percent Oxygen in Expired Air]

What are Normal VO₂Max Values?

The table below displays standard VO₂Max classification ranges for both men and women.

VO₂Max (mL•kg-1•min-1) for Women
Age (years)	Poor	Fair	Good	Excellent	Superior
20 – 29	≤ 35	36 – 39	40 – 43	44 – 49	50+
30 – 39	≤ 33	34 – 36	37 – 40	41 – 45	46+
40 – 49	≤ 31	32 – 34	35 – 38	39 – 44	45+
50 – 59	≤ 24	25 – 28	29 – 30	31 – 34	35+
60 – 69	≤ 25	26 – 28	29 – 31	32 – 35	36+
70 – 79	≤ 23	24 – 26	27 – 29	30 – 35	36+

VO₂Max (mL•kg-1•min-1) for Men
Age (years)	Poor	Fair	Good	Excellent	Superior
20 – 29	≤ 41	42 – 45	46 – 50	51 – 55	56+
30 – 39	≤ 40	41 – 43	44 – 47	48 – 53	54+
40 – 49	≤ 37	38 – 41	42 – 45	46 – 52	53+
50 – 59	≤ 34	35 – 37	38 – 42	43 – 49	50+
60 – 69	≤ 30	31 – 34	35 – 38	39 – 45	46+
70 – 79	≤ 27	28 – 30	31 – 35	36 – 41	42+