Understanding VO2 Max, The What How And Why
What Is VO2 Max? Can It Help My Running?
When you see the term VO2 max, it generally describes the incredible feat of an elite endurance athlete. Some of you may recall people marvelling over the incredible aerobic capacity of Spanish cycling legend Miguel Indurain.
Winner of five consecutive Tours de France from 1991 to 1995 and his exceptionally high VO2 max of 88. Ten years later, Lance Armstrong broke this consecutive wins record by notching up seven in a row. With a similarly elevated VO2 max of 84.
Armstrong’s wins were of course revoked in 2012 following the discovery of long-term doping offenses. But it nevertheless suggests that a high VO2 max is an indicator of supreme aerobic fitness (learn more by reading, Aerobic vs. Anaerobic Training).
Cyclists tend to dominate the top ten highest ever recorded VO2 max. Though a few runners also make a welcome appearance.
Steve Prefontaine who in the 1970’s with a VO2 max of 84.4 held the American record in seven different distance track events from 2,000 to 10,000 meters.
This begs the question, should all runners be aware of their VO2 max? Is it something we should be trying to improve, or something best left to the elites? To answer these questions, let us first take a closer look at what VO2 max actually represents.
What Does VO2 Max Measure?
VO2 Max is a measure of the maximum volume of oxygen (O2) your body can process when you are exercising. The ability to take oxygen from the air and deliver it via the lungs into the bloodstream. For use by your working muscles.
VO2 max measured in ml/kg/min, i.e. millilitres of oxygen per kilogramme of body weight per minute. With essentially two determining factors:
- How much blood your heart can pump out to the muscles with each beat (cardiac output)
- How efficiently your muscles can extract the oxygen from the blood and utilize it
Essentially, the faster your body can process oxygen the faster you will potentially be able to run. One of the reasons elite runners can perform so well at such low heart rates is the huge volume of blood their hearts are able to pump to their muscles with each stroke.
Although genetics play a major part in determining your VO2 max, there is certainly no doubt that in particularly mid distance (mile to 10k) runners have higher VO2 max values.
Does High VO2 Max Guarantee Race Wins?
In a word, no. Although VO2 max is a useful measure of aerobic capacity. It is important to point out that a high value will not guarantee a win. In fact, research shows it is a fairly poor predictor of race performance.
Just because you have a high aerobic capacity does not mean you have all the tools to fully benefit from it. There are obviously many other physiological and psychological variables at play. Running efficiency plays a huge part in performance.
For example, how fast you are able to run with a given amount of oxygen. That’s where running form, strength and many other factors will come into play. To date there is no lab test that can successfully determine the winner of a race. Please read Proper Running Form to learn more.
So How Can VO2 Max Testing Help Me?
Striving for a higher VO2 Max will not guarantee you improved performance. Though being aware of your current VO2 max can provide a useful way of optimising the design, intensity and effectiveness of your training sessions.
Left to their own devices, many runners struggle with training at appropriate intensities to meet their goals. When it comes to aerobic exercise, the effect of intensity on how our body reacts allows us to talk of three training zones:
- Aerobic Zone: Heart & lungs able to deliver enough O2 to the muscles to keep you moving
- Threshold Zone: Muscles struggling with amount of O2 being supplied (lactate accumulates)
- Anaerobic Zone: Muscles can no longer get enough oxygen, so you will soon have to stop.
To become a faster, stronger and less injury prone, most mid to long distance runners should be spending 70-80% of their training sessions in the aerobic zone, 20% in threshold and maybe 5-10% in anaerobic.
The reality is very different with many runners spending way too long in threshold. The results are inhibited gains in aerobic fitness and more susceptibility to injury.
Research shows that Heart Rate Maximum (HRmax) closely represents VO2 max, and given the ease and simplicity of monitoring heart rate this makes it a great way of keeping you in appropriate training zones.
The classic combo of chest strap and watch means you do not have to spend a fortune. Wrist sensors tend to provide less accurate results than chest straps. The relationship of HRmax and VO2max is as follows:
- 55% HRmax = 40% VO2max
- 70% HRmax = 60% VO2max
- 85% HRmax = 80% VO2max
- 90% HRmax = 85% VO2max
Using these values, we can update the aerobic zones we considered earlier to incorporate the following HRmax %:
- Zone 1: <80% HRmax (<75% VO2 max)
- Zone 2: 80-90% HRmax (75-85% VO2max)
- Zone 3: >90% HRmax (>85% VO2max)
When talking about HRmax, some of you may be familiar with the traditional method of subtracting your age from 220. A common treadmill (and coach) method.
There is unfortunately no scientific evidence for this method and indeed often throws up an incorrect estimation.
The only real way of accurately estimating HRmax is by monitoring your heart rate during a gradual run to exhaustion. As is the case for a lab based VO2 max test or by estimating it based on your VO2 max values.
To learn more about heart rate, monitoring and training, please read How To Understand The Heart Rate Training Zone For Running and How To Know If Heart Rate Training Is Right For You.
How To Calculate Your VO2 Max
The most accurate way of measuring your VO2 max is having a professional test in a lab with breathing apparatus. Measuring the amount of oxygen you consume whilst running on a treadmill. With the speed of the treadmill slowly increased over roughly ten minutes.
The amount of oxygen consumed also increases but eventually will plateau. Shortly before exhaustion means you have to stop and this amount is your VO2 max.
With the advent of modern technology, there are now alternatives on the market. If you do not fancy the expense of going to a lab or enjoy the prospect of having to run to exhaustion. Some modern GPS watches (e.g. Garmin Forerunner 230, 235, 630) include an inbuilt VO2 max test.
By measuring your heart rate and pace during a 12 minute run using a chest strap or wrist sensor (depending on the model of watch). Though studies show that the results are not as accurate as those produced in lab tests. Particularly in the case of wrist sensors, deviation is generally only around +/-5%.
The least accurate VO2 max test is one that not surprisingly involves no exercise at all. Certain watches on the market (e.g. Polar M430) estimate your VO2 max using based on data including your resting heart rate, age and typical activity level.
A test that essentially involves you laying down and relaxing for five minutes may sound attractive. Though results are particularly unreliable with deviation of +/-10%.
What Are Typical VO2 Max Values?
When it comes to defining physiological norms, there are nearly always exceptions. However, research does provide the following as indicators of typical VO2 max values over the indicated levels of running fitness:
- Untrained healthy male: 35-40
- Male runner: 55
- Competitive male runner: 65
- Elite male runner: 70 to 85
Women tend to have VO2 max levels 10% lower than men. Thought to be due to higher presence of essential fat stores and lower haemoglobin levels.
Whereas an untrained healthy male, typically has a VO2 max of 35-40. An untrained healthy female will therefore be somewhere around 27-31.
VO2 max values also vary according to the distances you run. Studies show that elite marathon runners tend to have a lower VO2 max values than mid-distance runners.
As race distance increases the maximal amount of oxygen one can deliver to the muscles becomes less important (running economy is a far more important factor in long distance running).
Looking at the other end of the spectrum, sprinters do not have particularly high VO2 max levels either. Because the energy system used for efforts lasting less than 20 seconds is not dependent on oxygen. VO2 max would therefore seem to be most relevant for runners focusing on distances between 1 mile and 10k.
In an article looking at VO2 max and HRmax, it is useful to also take a brief look at lactate threshold.
When it comes to predicting race performance, the lactate threshold test provides a far more accurate tool. The percentage of VO2max at which an athlete can perform relates to the amount of lactate in the blood.
Which is why lactate threshold is generally a better predictor of race pace than just VO2 max.
If we say VO2 max measures your aerobic potential, lactate threshold determines how much of that potential you can tap into during a race. Indeed, if two runners in a race have the same VO2max value but one has a higher lactate threshold, the latter is more likely to win.
Though Lactate was once regarded as a principal cause of fatigue and pain (and still mistakenly is by many runners and coaches), we now know that this is not the case. Though high concentrations of lactate do often correlate with muscular fatigue, lactate is not the direct cause.
To understand more, please read Bonking vs. Fatigue vs. Cramping: What You Need To Know.
Lactate produced by the body at low intensity exercise is in fact a source of energy production, used to create glucose from non-carbohydrate substrates such as lactate, glycerol, and amino acids.
Whilst the intensity of the exercise stays low, the body manages to recycle the lactate. But once a certain intensity is reached (the ‘lactate threshold’) this no longer becomes possible and so the concentration of lactate in the blood suddenly spikes.
Increasing one’s lactate threshold is thought to improve the efficiency of the functional capacity of the mitochondria in muscle cells allowing more oxygen to enter the cell membrane. This in turn will allow the runner to perform at higher levels for longer periods of time.
To increase your lactate threshold, you need to make sure that the majority of your training sessions (some studies suggest around 75%) are at or just below your lactate threshold. The test for lactate threshold is similar to the VO2 max Test in a lab in that you run on a treadmill at a progressively increasing speed.
Every five minutes, a pinprick of blood is taken, recording lactate levels. What the test is looking for is the speed you are running at when lactate levels start to spike. The intensity at which this occurs will be your lactate threshold, typically expressed as 85% of heart rate maximum (HRmax) or 75% of VO2 max.
VO2 max value is a useful identifier of your current aerobic capacity and monitoring future progression. It can also be used to determine optimum heart rate training zones. Especially if combined with lactate threshold values. Which will ensure your workouts are at a suitable intensity level for your goals.
By using these zones a runner can potentially reduce risk of injury. Whilst at the same time benefiting from safe increases in overall running volume and frequency.
Many runners are at first shocked by how much slower they need to run in order to stick to their training zones. With every cell in your body screaming at you to speed up. Sticking to the new pace is not easy.
To learn more please read How Running 80% Easy Could Make You 23% Faster.
You may even find you need to introduce a few walking intervals in the early stages to stop the heart rate from exceeding the zone’s upper limit. I advise most runners to undergo at least a week or two of lower intensity running to allow for the necessary adaption.
After that time, many will start to embrace the novel sensation of training more often at a lower intensity.
For some, physiological tests may sound like it makes running far too complicated. But if you do find yourself hitting plateaus or cursed by reoccurring injury, maybe now is the time to change from running hard to running smart.