Cardiovascular exercise has a plethora of known benefits. Such benefits range from heightened athletic performance to improved mental health. Athletes interested in improving their endurance should know how to calculate VO2 max, or at least know what it is. In this article I’ll explain just how to do this!
Okay, so let’s get start off with the basics.
The abbreviation VO2 stands for the volume of oxygen consumed. This should not be misinterpreted as the amount of air inhaled (VI). VO2 is the amount of oxygen that your body utilizes for energy.
This will become more evident as the article progresses as you’ll see why someone expires less carbon dioxide (CO2) than they inspired oxygen (O2). Unlike the Wingate (Cycle) test, you won’t need a stationary bike to test your VO2 max. VO2’s are typically analyzed on a treadmill in a laboratory setting.
An individual’s VO2 max is an indication of how much endurance they have. More specifically, it measures cardio-respiratory fitness. It is the maximum amount of oxygen that an individual can utilize during exercise. This is very important for an endurance athlete.
People who are sedentary have pretty low VO2 max’s. This is because their body can’t utilize oxygen at a fast enough rate to keep up with the demands put upon it. So, the higher the VO2 max is, the better shape you’re in. Of course, other factors come into play such as lactate threshold and others, but even so, a VO2 max is a great indication of your fitness level. So, where do you compare to the general population? Check out the chart below to find out!
|13-19||<25.0||25.0 – 30.9||31.0 – 34.9||35.0 – 38.9||39.0 – 41.9||>41.9|
|20-29||<23.6||23.6 – 28.9||29.0 – 32.9||33.0 – 36.9||37.0 – 41.0||>41.0|
|30-39||<22.8||22.8 – 26.9||27.0 – 31.4||31.5 – 35.6||35.7 – 40.0||>40.0|
|40-49||<21.0||21.0 – 24.4||24.5 – 28.9||29.0 – 32.8||32.9 – 36.9||>36.9|
|50-59||<20.2||20.2 – 22.7||22.8 – 26.9||27.0 – 31.4||31.5 – 35.7||>35.7|
|60+||<17.5||17.5 – 20.1||20.2 – 24.4||24.5 – 30.2||30.3 – 31.4||>31.4|
Male (values in ml/kg/min)
|13-19||<35.0||35.0 – 38.3||38.4 – 45.1||45.2 – 50.9||51.0 – 55.9||>55.9|
|20-29||<33.0||33.0 – 36.4||36.5 – 42.4||42.5 – 46.4||46.5 – 52.4||>52.4|
|30-39||<31.5||31.5 – 35.4||35.5 – 40.9||41.0 – 44.9||45.0 – 49.4||>49.4|
|40-49||<30.2||30.2 – 33.5||33.6 – 38.9||39.0 – 43.7||43.8 – 48.0||>48.0|
|50-59||<26.1||26.1 – 30.9||31.0 – 35.7||35.8 – 40.9||41.0 – 45.3||>45.3|
|60+||<20.5||20.5 – 26.0||26.1 – 32.2||32.3 – 36.4||36.5 – 44.2||>44.2|
How to calculate VO2 max?
The true way on how to calculate VO2 max is not done by simple online calculators or mathematical equations that include your BMI, age, or some other similar value. One of the best ways get your VO2 max is in a lab. This can be done several ways, but for the sake of this article, we’ll discuss how it can be measured by using a breath analyzer.
There are a lot of things we look at and must calculate before we even get close to coming up with a VO2 max. Nevertheless, if you’re an athlete interested in learning how to calculate VO2 max or you’re just curious to see where you are fitness-wise, many colleges and universities have labs where you can undergo a full test of your body’s ability to consume and utilize oxygen.
There are essentially 5 steps for figuring out how to calculate VO2 max after you perform a graded test in a lab. Don’t worry if it looks overwhelming! Below the 5 steps is an actual lab report on how to calculate vo2 max. It gives very detailed explanations of the metabolic pathways involved, the equipment used, and much more.
The first thing you’ll want to do is calculate the temperature of exhaled air. This is also referred to as calculating T-gas. For this equation, you’ll need to know that a normal body temperature is 37*C. So, T-gas = ((37*C – room temperature in *C)/2) + Room Temperature
Then, you’ll want to standardize the gas volume. This is done by calculating the volume of air expired at standard temperature and pressure, dry (VE(STPD)). However, to calculate this value, you’ll need to know the atmospheric temperature and pressure, saturated (VE(ATPS)). This value and several others will be given to you from your lab results or the lab conditions themselves.
Also, keep in mind that several of the values throughout these steps are constants. The mmHg value will be based on the location of your lab. So, VE(STPD) = VE(ATPS) X (273*C/(273+T-gas)*C) X (PB-PH2O)/760mmHg
Next, you’ll want to determine the volume of oxygen expired (VO2E). Here, you’ll need to know the percentage of oxygen in the expired air (FEO2). So, VO2E = VE(STPD) X FEO2
Step 3 has you determine the volume of air inspired (VI). We’ll first calculate the fraction of nitrogen (FEN2) in the expired air. You’ll need to know the percent of oxygen in the expired air (FEO2), as well as for carbon dioxide (FECO2). So, FEN2 = 1.00 – (FEO2 + FECO2)
Then, we’ll want to calculate the volume of inspired air (VI). The only constant in this equation is the value we divide by, which is 0.7904. So, VI = VE(STPD) X FEN2/0.7904
Next, you’ll determine the volume of oxygen inspired (VO2I). A constant with this equation is that the fraction of oxygen in room (inspired) air (FIO2) is 0.2093. So, VO2I = VI X 0.2093
Finally, here we’ll actually calculate oxygen consumption (VO2). So, VO2 = VO2I – VO2E
Now let’s try to put all of this information together in a real world example of a VO2 max experiment including one male and one female. Below, is the full length lab report.
Here’s an example of a real VO2 max experiment including how to calculate VO2 max
In this lab, we measured the oxygen consumption of a male and a female participant on a treadmill. Each participant was connected to a metabolic analyzer to measure and record the volume of air and analyze the composition of the exhaled air, among other things. Progressively increasing the speed on the treadmill, each participant was forced to intake greater amounts of oxygen and expel greater amounts of carbon dioxide.
The purpose of this lab was to be familiar with the procedures and calculations involved in determining oxygen consumption and to have a better understanding of how to calculate an individual’s VO2 max. I hypothesized that the volume of oxygen consumed would significantly increase as exercise intensifies, as well as seeing an increase in the percent concentration of carbon dioxide in the expired air.
Subjects & Lab Conditions:
The male participant in this lab was 25 years old, 195 cm tall, and weighed 108kg. The female participant was 25 years old, 170 cm tall, and weighed 67 kg. The lab conditions were as follows: 23*C, 32% humidity, 766 mmHg, and a PH2O of 21.068.
Instrumentation & Protocol:
The participants each used a Cardiac Science TM65 Treadmill for the lab. They were then both individually connected to a metabolic analyzer by the way of the open circuit system. This system works by having the subjects wear a one-way valve with membranes that allow air to travel in only one direction.
As the subject inhales, air enters from one side of the valve. As he or she exhales, the air exits through the other side of the valve into a collection tube that is connected to a computer system. This system measures the volume and analyzes the composition of the exhaled air.
Once they were properly connected to the Parvomedics Trueone 2400 Metabolic Analyzer, they walked on the treadmill for five minutes at 3mph. The volume of air expired and the percentages of O2 and CO2 were recorded during the last minute. After the first five minutes have elapsed, the participants jogged for three minutes at 5mph. Once again, the volume of air expired and the percentages of O2 and CO2 were recorded during the last minute.
Finally, the participants ran at a maximal speed for three minutes. This ended up being 7mph for the female and 8mph for the male. During the last minute, the volume of air expired and the percentage of O2 and CO2 were recorded.
After the lab was over, the participants then walked for 3-5 minutes in order to cool down their bodies and minimalize blood from pooling in their lower extremities.
The results show a significant increase in volume of air expired as exercise intensity increased. As each stage progressed, the Ve was virtually multiplied by two. It also showed constant increases in the percent concentration of oxygen and carbon dioxide in their expired air. The male’s VO2 greatly jumped from 1.4 L/min to 3.43 L/min after going from a low intensity to a moderate intensity.
The trend continued upward as he reached the high intensity. The female participant experienced a similar result by going from 0.79 L/min to 1.75 L/min after going from a low intensity to a moderate intensity. Her VO2 continued to rise as she entered into a high exercise intensity. The tables below represent the results found from our experiment:
Male Subject: Age: 25 Ht: 195 cm Wt:108 kg
Female Subject: Age 25 Ht: 170 cm Wt: 67 kg
In this lab, we observed the oxygen that the body uses to produce energy aerobically. Measuring oxygen consumption in this lab allowed us to get a sense of the relationship between exercise intensity and oxygen utilization. By recording the volume of oxygen inspired, as well as the volume of carbon dioxide expired, we were able to measure the total volume of oxygen consumed at relative levels of low, moderate, and high exercise intensities.
The bulk of the aerobic pathways used in this lab can be found in the mitochondria (powerhouse) of the cell. These consisted of glycolysis, glycogenolysis, the Krebs cycle, and the ETC. Under aerobic conditions (slow glycolysis), the ETC can easily accept hydrogen pairs from NAD at the glyceraldehyde-6-phosphate step in glycolysis. This makes it unnecessary for much lactic acid to be made.
Thus, the reason as to why aerobic exercise allows for much longer bouts of exercise to occur. Aerobically, one blood glucose molecule yields a total of 32 ATP that the body can use as energy and 33 ATP from a glycogen molecule. In fact, only 6% of those 32 ATP are produced in the first metabolic pathway (glycolysis). The remaining ATP are produced via the Krebs Cycle and the ETC, both of which are located in the mitochondria of the cell. Thus, shows the importance of the mitochondria as it relates to exercise performance.
The purpose of this lab was to develop a sound understanding of the theory involved in determining oxygen consumption and to also be able to successfully calculate the proper equations to determine oxygen consumption. With the final data presented, I accept my hypothesis that oxygen consumption will significantly increase as exercise intensity increases.
Final thoughts on how to calculate vo2 max
Knowing how to calculate VO2 max can be very useful to you. Whether you’re an endurance athlete, a fitness enthusiast, or just someone interested in exercise physiology and how bouts of exercise effect the body, then knowing how to calculate VO2 max can definitely benefit you! It can help to give you an idea of your fitness level as it relates to respiratory fitness, specifically oxygen utilization.
Also, you’ll never have to worry about having to calculate these figures all on your own if you ever do an actual VO2 experiment as the lab attendants will easily be able to calculate any value you’ll need. In conclusion, I hope the information laid out herein has given you a clearer understanding of how to calculate VO2 max and why it’s such an important value for endurance athletes.
Kraemer. R. R., (2015). Exercise Physiology – Kinesiology 329. Laboratory Manual. Pgs. 20-23.