Workout Wednesday: Improving Your V̇O2max
Let’s cast our minds back 15 years. Most of us owned absolutely no wearable health devices, and as such, we had no concept, quantitatively at least, as to how fit we truly were. Maybe you cycled three times a week, and you told friends and family that this made you ‘pretty fit’, but even then, you weren’t sure how this placed you against the average human being. You could have visited a physiology lab to get tested, but this seemed an inconvenience, not to mention the price, for essentially a number.
Simpler times.
Let me bring you back to the present again. You’re probably within 2 feet of a device which will tell you how fit you are, as well as your average heart rate, heart rate variability, how well you slept, and maybe even whether you should consider training today. Somewhere along the line, we stopped listening to our bodies in an attempt to cheat the ageing process. We have become obsessed with ‘longevity’ and ‘optimisation’, although nobody ever seems capable of telling you what this actually means.
We hear so frequently about how those who live longest have great fitness levels and a brilliant V̇O2max score. However, is this the be-all and end-all, or do we require some nuance here? (Hint: Obviously yes). Granted, improving one’s V̇O2max is important, and I’ll give some examples of how I would go about achieving this below, but I also want to provide some context, too, because life is not as simple as finding the optimal strategy for X to achieve Y.
Housekeeping
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What is V̇O2max?
Ok, before we begin, let’s outline how to denote it, because by denoting it correctly helps us understand exactly what V̇O2max is.
V̇O2max
You’ll notice a few things:
The ‘V̇’. There is a dot above it, which is important. Whilst the ‘V’ itself refers to ‘volume’, the dot above the letter indicates that we are measuring a rate, or volume per unit time.
O2. Ideally, a small ‘2’ in subscript here. Also, it is a letter ‘O’ (not the number zero/0) because we are talking about Oxygen here. It’s not a sequence of numbers or a mobile phone provider.
‘Max’ simply refers to maximum.
More often, we will simply see “VO2max”. The dot and small ‘2’ tend to disappear in text for convenience, so I will do the same from here on.
Anyway, when we put it all together, we arrive at the very definition of what VO2max is:
“The maximum rate of oxygen uptake and utilisation during exercise”
How do we find out our VO2max?
It can either be estimated using heart rate data from wearable devices or tested in a laboratory.
For context, let’s review how VO2max is measured in a lab.
In the majority of cases, the test is performed on either a stationary bike or a treadmill. The subject will wear a mask which measures, amongst other things, the content and volume of the gas being inhaled and exhaled throughout the test. The subject starts exercising at a gentle pace, and the difficulty is increased at regular intervals until the subject hits a combination of pre-determined exhaustion criteria. These criteria tend to include, amongst others:
VO2 plateauing despite increased speed and intensity of test;
Blood lactate exceeding a certain threshold (varies by test);
An RPE (rating of perceived exertion) of >17/20, or 9/10;
Achieving a pre-determined percentage of the predicted maximum heart rate.
Once the test is terminated, the highest recorded VO2 is noted. This is then referred to as the VO2peak, since it is the highest score observed within the test. The majority of practitioners erroneously refer to this as the subject’s VO2max. Since VO2max is, by definition, the maximum possible oxygen uptake, there is a possibility that the subject’s VO2max is fractionally higher than the recorded VO2peak, but this is often fractional.
What does the number mean?
Whether you’re being given an estimate from your wearable device or you’ve been to a lab to determine your VO2max, you’ll have a number specific to you. If you’re lucky, you’ll even be given a morsel of context which tells you how ‘good’ your score is.
I’ve attached my Garmin score below as an example.
In my case, the screenshot just says ‘55’. But what does this mean?
Well, VO2max is generally measured in millilitres of oxygen per kilogram of bodyweight per minute (ml/kg/min). This is fair, as it allows us to standardise pretty well for our size (and therefore lung capacity, as heavier people generally have bigger lungs). The fact that VO2max is measured per minute is, again, proof that we are working with a rate here, and that the dot above the ‘V’ is important.
Ultimately, this means that there are two ways in which we can improve our own VO2max score:
Lose weight
Improve fitness
Losing weight may be possible and sensible for those who have excess adiposity, but it probably isn’t recommended in the sphere of sport and exercise performance. Improving fitness is something that we should be aiming to achieve, but even then, there’s a limit that we have no control over…
The genetic component
VO2max can be improved by lifestyle changes. However, roughly 50% of the trainability in VO2max is genetically determined. If you’re really lucky, you may be able to improve VO2max by ~20% through exercise intervention. This is why elite athletes with VO2max scores of 80+ are just different gravy (although VO2max is not the only reason they are elite performers, but that’s another story).
Is the research surrounding VO2max being misinterpreted?
“When a measure becomes a target, it ceases to be a good measure.” - Goodhart’s Law
Okay, this quote is a bit tongue-in-cheek, but I do think it raises a valid point. If you take another look at my personal score in the image above, you’ll see that it is ‘excellent’ for my age, weight, and sex. However, a ‘superior’ category does exist, and would include a score of >56. Therefore, wouldn’t training to improve my VO2max by one point to the next category up be a good target?
When posed with this problem, many people would hop onto Google, and ask: “What is the best workout to improve my VO2max?”. Therein lies the problem. Improving VO2max shouldn’t be a target, but instead simply a product of your training. The same should go for:
Weight loss and body recomposition. Yes, diet and exercise to lose excess fat is a good motivator and target, but it is the process of eating more healthily and being more active which is far more important.
Grip strength. We know that this is a great index for whole body muscular strength, but we wouldn’t aim to just improve grip strength. If this was the case, we would just isolate the forearm muscles. Instead, improving whole body strength is the sign of a successful intervention.
VO2max session examples
I can hear you all shouting at me through your computer screens:
“Norwegian 4x4s”
“800m reps on a track”
“Hill sprints”
“Pyramid sessions”
…this is the first clue that there is not one true best method.
REMEMBER: The focus should be on the process, not necessarily the outcome. With that in mind, let’s look at what we should be including as part of a sensible cardiorespiratory exercise training plan.
Number 1: Lots of easy training volume
Yes, believe it or not, running 4x4 minutes once a week is not sufficient to improve your VO2max after a certain point. The same goes for 10x20s hill sprints.
This is where the ‘Zone 2’ idea can be useful. It represents a low-intensity stimulus, performed regularly, to raise the heart rate but not leave you gassed. It allows us to train for longer periods of time, and in a sustainable manner, and if you want to improve your fitness, your plan needs to be sustainable.
To accumulate training volume at an easy intensity, go for a fast walk, a light jog, a gentle cycle, or an easy swim. But do as much of it as you can sustainably tolerate without risking overuse or injury. This is where coaches and fitness professionals are able to give you personalised advice. This is the foundation of your training, and you cannot escape it. In fact, it doesn’t even have to be structured exercise. Playing with your kids, walking to school, gardening, housework - these are all examples of activities which can increase the heart rate adequately in an unstructured manner.
Number 2: Some higher intensity work
Some. And vary it.
Let’s look in detail at the study on Norwegian 4x4 training. These subjects performed 3 bouts of interval training (4 minutes of effort, 3 minutes of rest, repeated 4 times) each week for 8 weeks and saw a 7.2% improvement in VO2max1. They didn’t go hell-for-leather on the rowing machine 6 days each week.
However, a parallel group performed a shorter interval protocol. This group ran all out (90-95% max heart rate) for 15s, followed by 15s rest, and repeated this *47* times. These guys saw an impressive average of a 5.5% VO2max improvement. The lesson: There is no one-size-fits-all for improving VO2max. For most people, whether your VO2max improves by 5.5% or 7.2% in 8 weeks isn’t important. The participants in this study were also already pretty fit (VO2max scores of 55-60 even before the training plan started), so if your base level of fitness is lower than theirs, you may be likely to see a greater improvement in 8 weeks.
Most people also ignore the fact that every training session was performed on a treadmill at 5.3% incline. This is lab research, not the real world. Give me an outdoor run or cycle all day long!
In the real world, as long as you’re exposing yourself to pretty high heart rates, you’re probably going to be alright. For those of you who love exercise zones, we are talking zones 4/5 here. Try a variety of sessions: 4x4, 15s/15s, 800m repetitions, 400m repetitions, tempos, thresholds. The only requirement is that you work hard enough in the ‘work’ intervals, and ensure that the ‘rest’ intervals are sensible enough to allow you to complete at least 20 minutes of ‘work’ (outside of a warm-up and cool down).
For example:
4x4 protocol is 4 minutes on, 3 minutes off, x 4 = 28 minutes
15s on, 15s off, x47 = 23.5 minutes
8x800m reps (aim for a pace which equates to your 5k goal pace) with 2 mins rest after each effort = 40 mins.
3x8-minute tempo (a hard but sustainable pace) cycles or runs would be 24 minutes plus the rest between.
You can even vary the mode. Swim, run, cycle outdoors. Indoors, at a gym, you’ve got row ergs, ski ergs, assault bikes to name a few machines.
Putting it all together
If you want to improve your VO2max, you need to improve your training plan.
Build your aerobic base by performing as much low intensity (Zone 2) work as you can without risking injury, etc.
A couple of times each week, go much harder, and accumulate at least 20 minutes of zone 4/5 ‘work’ per session.
Repeat for 8-12 weeks. If you’re unable to stay consistent, play around with reducing your aerobic base work, and vary the modes and styles of intervals, tempos or thresholds.
Thanks for reading!
I appreciate that there’s a lot of detail here, so if you’re in any doubt, you can message me by hitting the button below. Thanks for your support and see you next week!
Helgerud, J., Høydal, K., Wang, E., Karlsen, T., Berg, P., Bjerkaas, M., Simonsen, T., Helgesen, C., Hjorth, N., Bach, R., & Hoff, J. (2007). Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine and science in sports and exercise, 39(4), 665–671. https://doi.org/10.1249/mss.0b013e3180304570