I tried the longevity test this doctor swears by. How did I score?

Don’t tell me about your sleep score. I have no interest in your 5k time. I’m utterly indifferent to your resting heart rate. But there is a health and fitness number I am obsessed with because it’s the undisputed best at gauging our longevity. If you don’t know your VO₂ max, do you even care about your body?

Truth be told, until recently very few people did know their VO₂ max, which is a measure of how much oxygen you can convert into movement while exercising at full capacity. I didn’t know mine until last week, partly because it requires an actual scientific test involving wearing a mask while running on a treadmill. But according to Livvy Probert, the head of science at the Stone London gym, a personal training facility that offers the test for £150, searches for VO₂ max have rocketed in the past six months and “the more people are talking about it, the more everyone wants it”.

Much of this new interest can be attributed to Peter Attia, the Canadian doctor and podcaster whose 2023 book Outlive: The Science and Art of Longevity highlighted VO₂ max as one of the best indicators of long-term health, stressing that even for people who are not particularly fit, moving up just one level delivers a really significant reduction in their chances of dying from disease.

A study carried out in 2018 at the University of Innsbruck found that “VO₂ max is the strongest independent predictor of future life expectancy”. Another research project by the Cleveland Clinic in the US said: “Extreme cardiorespiratory fitness was associated with the lowest risk-adjusted all-cause mortality compared with all other performance groups.”

The reason is your VO₂ max gives a very true picture of your underlying fitness. It’s a whole-body effort involving strength, heart health and lung power. And the better your overall fitness, the less likely you are to die of heart attack, diabetes, cancer and pretty much all the things that shorten lives. “It’s how well can your heart pump blood around your body, how well can your lungs oxygenate that blood, how well can your muscles then use that oxygen,” Probert says.

The number represents the millilitres of oxygen per kilogram of body weight your body can use every minute at maximum intensity. As a general guide, 42.4 is good for a fortysomething man and 36.3 is good for a fortysomething woman. In your fifties, 39.2 for a man and 33 for a woman are good scores. Attia, who is 51, revealed in a podcast that his own score is in the low to mid-50s.

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Naturally, when I arrive for my test I am quietly anxious to come out with a respectable number. Probert has a master’s in sport and health sciences, but also considerable expertise in diplomacy learnt at VO₂ max feedback sessions. “There are a lot of people who train and maybe think they’re working quite hard, but not necessarily doing the right things for what they need, and it will come out lower than they hoped.” Activities such as Pilates and yoga, although incredibly beneficial in other ways, will not in themselves be sufficient. Jack Hanrahan, a fitness coach who helps clients train to improve their VO₂ max, says: “If you’re not doing any cardio you would not expect your VO₂ max to be high.”

Before I begin, I am handed a surprisingly substantial mask to wear over my face. It’s very Bane (the Tom Hardy baddie in the Batman film The Dark Knight Rises). This is my first time on a running machine dressed as a psychotic comic book character and there is definitely an adjustment period. Asked for my music choice, I select AC/DC, needing all the boost I can absorb for this very public test of my capabilities.

The machine is set at a two-degree incline and I start my easy jog. As Back in Black plays I am unnervingly thinking about my internal organs. I can see my heart rate raising on a dial in front of me while Nico, the gym trainer, announces each two-minute increase in pace. I don’t often run at speed on a machine (with or without a massive mask) so I feel a little uncoordinated and out of control as we start to really speed up. My legs are blurry cartoon limbs under me and every two seconds or so I think, “Is this it?” Finally, I call it at a heart rate of 163, having completed four increasingly fast and exhausting two-minute rounds.

The calculations are made and my score is revealed. Because this isn’t about me but about the general benefits of knowing and improving your VO₂ max, I won’t include my figure here. Just kidding — it’s 48.3, which places me in the97th percentile for my age bracket, very near the top. In fairness, I’ve only just turned 60, so I’m at the youngest end of my very mature cohort, which goes up to 69.Good scores for this age group are 35.5 for men and 30 for women. I’m quietly satisfied. Meaning I’ve told everyone I’ve met since, including a barista.

I work out every day in various ways — lifting weights, hill running, punching a bag — but until now I wasn’t at all confident I was doing the right kind of movement for this overall fitness exam. So I am pleased. But even if you’re not a fitness nerd like me, being aware of how to improve your VO₂ max is important, says Rhona Pearce, the physiology lead at Loughborough University, because typically, like most aspects of fitness, it declines as you get older.

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“Naturally, VO₂ max declines with age at 7 per cent per decade for women and 10 per cent for men,” Pearce says. “Training can offset that: a study of 579 men showed that after 11 years only a one millilitre per kg of body weight increase resulted in a 9 per cent risk reduction in all-cause mortality.”

To improve your VO₂ max — even if you are never going to bother with the actual test — the key is to undertake two kinds of cardio, Provert says. The first is long and fairly gentle. “This is your low-intensity steady-state cardio — long, slow runs, for example — and this will improve the number of mitochondria, the energy-making powerhouses, in your cells.” This could be any extended aerobic activity: swimming, cycling, rowing, or walking with a weighted pack, Hanrahan says.

The other kind of cardio is somewhat more vigorous, one in which you are aiming to raise your heart rate with a sprint, then recover. “You want to get your heart up to maximum and keep it there for 30 seconds, then recover all the way back down to a gentle jog, and then do it again,” Provert says.

Intense training like this works by stimulating your heart and lungs to become stronger, rather like lifting heavy weights helps to build bigger muscles, Hanrahan explains. But he warns that, as with lifting weights, those not used to very tough heart and lung workouts should start slowly and steadily build up. Sleep and good nutrition will also have a significant impact on your VO₂ max score. Without enough rest and fuel to power your workouts, it will be much harder to progress, Hanrahan says.

Even if you don’t do the test, Hanrahan suggests tracking your performance at low-intensity aerobic work — for example, looking at your watts on a cycling machine or rowing machine — and trying to progress.

I think, if I’m honest, that I’m still more interested in activities that will enhance my upper body in a slim-fit T-shirt than improve my VO₂ max score. But learning about it has made my actual fitness suddenly very visible and real, and that’s motivating. And this isn’t a sentence I was expecting to write, but do ask your gym if they have a heavy plastic mask you can gasp into — I promise your result will be fascinating.

Ways to build your VO₂ max

For novices
If you rarely exercise, brisk walking is your starting point. Almost any movement will improve your figure, but if you’re able to keep going for an hour at a time, that’s best.

For improvers
Do two one-hour Zone 2 low-intensity cardio sessions a week, which can be walking with a weighted pack, running, cycling or swimming at 60 to 70 per cent of your max heart rate. Once this aerobic base is built, you can try medium interval training once a week. This should be tough, but take you well short of your maximum heart rate. Perform some dynamic stretching, then do a slow ten-minute jog to warm up. Then run for two minutes at a speed that feels like a moderately challenging effort. After two minutes, walk slowly to allow your heart rate to come down and your breathing to normalise. Do walk for two minutes, but if you need longer to recover that is fine. Repeat this sequence five times.

For the relatively fit
After roughly three months, you can graduate to higher-intensity running in the intervals. Again, no more than once a week. Meanwhile, stick with your two Zone 2 cardio sessions a week.