How’s that? You feeling OK?”
I answer Joe, the peppy young sports science guru from My Vital Metrics, in the only way possible while wearing a cumbersome, Bane-from-Batman-style mask over my nose and mouth and jogging on a treadmill – two thumbs up and what can only be described as an affirmative chirrup
“Great! I’m just upping the incline again.”
Another thumbs up from me… although it isstarting to get noticeably more arduous with each added degree of steepness. Sweat dripping off me and audibly gasping for air, I channel my inner Kate Bush – “keep running up that hill!” – and plough on. Only a few minutes more and I’ll find out the magic number that forms a crucial part of my overall health and longevity potential
I’m here at a specialised clinic in east London to get my VO2 max measured. I’d never heard the term until a few years ago; now, it seems to be cropping up everywhere, having gone from the preserve of elite athletes to the health and wellness mainstream, with more and more content online around how to “maxx” your max
So what is it, exactly?
“In its strictest sense, VO2 max is describing something called oxygen consumption,” says Professor James Hull, consultant respiratory physician at The Institute of Sport Exercise and Health (ISEH). “It’s a measure that describes the amount of oxygen that the body is able to use and metabolise.” As we exercise, and our exertion level goes up, more oxygen is consumed – and the amount that’s able to be consumed is dependent on the efficiency of the interactions between our muscles, circulation, heart and lungs.
“Overall, it’s an integrated measure of your cardio, metabolic and respiratory fitness or capability,” adds Hull
Though high-tech equipment is employed to test it these days, the fundamental concept of VO2 max has been around for well over a century
It was first discovered by a British physiologist named AV. Hill in the early 1900s. He made participants run around a grass track while wearing a mask over their mouth with a long hose coming out of the end; Hill or one of his team would ride behind them on a bicycle while holding up a meteorological bag to capture the air they expired. He found that, although the amount of oxygen consumed increased the faster people ran, there was always a ceiling, a point at which it levelled off. This was the maximum volume of oxygen an individual was able to consume – aka, their VO2 max.
The premise remains the same, though today it’s measured by putting an individual on a treadmill or bike while heart rate monitors and an oxygen mask are attached. The strenuousness of the exercise goes up gradually over the course of about eight to 15 minutes after an initial warm-up. The idea is to work to failure – stopping when you’ve reached your absolute limit
VO2 max is usually expressed as the maximum volume of oxygen in millimetres, per kilogram of bodyweight, per minute that can be utilised when you’ve reached peak exertion
In cardio fitness terms, the higher the VO2 max, the better. Scores range from around 12 ml/kg/min, typically the minimum threshold required to walk unassisted (this can drop under 10 for those with severe, end-stage congestive heart failure or extreme physical debilitation), to up to around 95 ml/kg/min for male and 85 ml/kg/min for female elite endurance athletes
Scores are separated into five categories: poor, fair, average, good and superior. The cut-off points for these brackets are adjusted for biological sex and age; VO2 max decreases as we get older
“Ageing has deleterious consequences for just about every system in the body, and it’s also inexorable – we can’t stop it,” says Dr Greg Grosicki from health tracker Whoop’s research science team. “But being physically active over time is also the best way to prevent it.” One study found that, although VO2 max is affected by the ageing process, dropping by 10 per cent per decade on average, it can improve by approximately 15 to 20 per cent at any age with regular endurance training.
It’s quite a powerful tool, way more powerful for an average person than, I would say, even for athletes
Dr Harpal Bains, longevity expert
Around 50 per cent of our VO2 max will be determined by genetics, while the other half is down to how we exercise
It’s obvious why professional athletes at the top of their game might be interested in VO2 max; at that level, the smallest micro-gains in performance can be the difference between medalling and coming in the middle of the pack. But, increasingly, it has been recognised as a metric that might be more beneficial for “civilians” to be aware of. Far from being a simple test of cardiovascular fitness, it’s now held up as a key measure in the burgeoning world of longevity medicine
Dr Andy Galpin, one of the world’s leading exercise physiologists, espouses VO2 max as the greatest predictor of not just lifespan, but healthy lifespan (living better for longer); Peter Attia, podcaster and author of Outlive: The Science and Art of Longevity, has consistently asserted that “VO2 max is the singular most powerful marker for longevity”; Bryan Johnson, the infamous billionaire poster-boy for experimental longevity medicine, often cites it as the ultimate indicator of overall health.
“It’s quite a powerful tool, way more powerful for an average person than, I would say, even for athletes,” says Dr Harpal Bains, founder and medical director of Harpal Clinic, a UK private practice specialising in functional and longevity medicine. “The real utility is in the everyday person who is fairly sedentary – and them making changes based on the implications of that number.”
In fact, one study found that the biggest longevity gains happen when a person moves from the least-fit group to modestly fit, dropping their mortality risk by nearly half
A review of scientific papers from the University of Innsbruck found that VO2 max is the strongest independent predictor of future life expectancy in both healthy and cardiorespiratory-diseased individuals; numerous studies have reported that it has a significant influence on survival rate in patients suffering from lung and/or cardiovascular diseases and cancer
The general public seems to be grasping this link with overall health more and more. Joe tells me that, of the influx of clients who come in to get tested at My Vital Metrics, roughly 80 per cent will cite health as the primary motivation for wanting to know their VO2 max. Most health wearables have added a VO2 max metric to their suite of data in recent years in response to user demand
It’s important to note, however, that the only way of finding out your real VO2 max score as an individual is to go, in-person, to a lab or clinic and get it tested like I did – complete with oxygen mask
Any number you’re given from a tech wearable, such as a watch or heart rate monitor, is not personal to you, but calibrated from large data sets – the device is estimating what your VO2 is likely to be based on your weight, sex, activity level and heart rate, comparing these against existing population data. These estimates vary wildly in accuracy depending on the brand of wearable and the individual
Studies looking at the Apple Watch, Garmin Fenix 6 and Fitbit have found a mean absolute percentage error of 7 to 16 per cent. Overall, they consistently underestimate VO2 max in fit people, and overestimate it in unfit people
Regardless, the real benefit here can be in seeing your original estimate as a baseline, and letting that motivate you to move the dial, improving your fitness through increasing cardio or high-intensity exercise
The fixation on VO2 max misses out on our ideal goal of diversity of exercise
Eric Topol, cardiologist
The experts I speak to stress that it’s not really worth obsessing over your VO2 max number specifically – what’s far more indicative of good health and improved longevity is a holistic, balanced approach that incorporates cardio, strength and stability training. The latter two are just as fundamental when it comes to having better health outcomes as we age
Some have argued that far too much importance has been placed on VO2 max in general. Many of the studies often quoted as linking better VO2 max with reduced mortality risk aren’t based on VO2 max data at all – they are based on physical activity tests and METs (Metabolic Equivalent of Task) data, which measures how much energy someone’s body uses during physical activity. Though the two are frequently conflated, they’re different metrics
“The fixation on VO2 max, which is not actually supported by the data, misses out on our ideal goal of diversity of exercise, including strength and balance training,” warned Eric Topol, an American cardiologist and author of Super Agers: An Evidence-Based Approach to Longevity, earlier this year in a blog post entitled “The Flawed VO2 Max Craze”
It’s vital to look at the big picture, too. “One has to be cautious about the type of individual that you’re looking at,” advises Hull. He cites this example: you can be an incredibly fit, muscular, relatively high BMI individual, working out well, eating the right food, sleeping well – and have a VO2 max that’s much lower than a very underweight endurance runner who eats and sleeps poorly and is highly stressed. “Using that marker as a tick box index of ‘am I in good health, or am I in the right place for long-term good health?’ is clearly not the right thing.”
Still, Bains believes that “knowledge is power” when it comes to something like VO2 max
“Sometimes knowledge propels you to take action – let’s say you come back with a really good result, it might motivate you to keep it. If you come back with a really poor result, it might motivate you enough to do something to change it.”
So, scores on the doors time: what’s my VO2 max? I’m a mixture of smug and plain relieved when Joe tells me that my number, 47.9 ml/kg/min, puts me in the highest category – superior – for my age and sex. “That’s a really good score,” he says, “But with the right training, you could probably up that number to 50.”
What does the “right training” look like? Unlike exercising for weight loss, which requires low-intensity movement to keep your heart rate in the fat-burning zone, upping your VO2 max is all about high-intensity interval training
Joe recommends I add in a session of HIIT once or twice a week, specifically Norwegian 4x4s – a workout consisting of four four-minute, high-intensity work intervals, each separated by three minutes of active recovery, eg four minutes of fast running followed by three minutes of an easy jog or fast walk
VO2 max isn’t everything, and “maxxing” it is far less important than striking a balance between building cardio fitness, strength and stability, plus prioritising a good diet and sleep, if the goal is long-term health
But Bains is right – knowledge ispower. And if knowing the number can spur you on to step up your game and prioritise your fitness? It’s definitely better to be in the know
