VO2 max explained: what the number means at 45 if you sit down all day

What people say when they first see the number

“Is it good?” That is always the first question, usually the moment they step off the bike. I can indicate there and then where they sit for their age. The full answer comes at the results review, once it sits alongside everything else from the Longevity Assessment.

What most people expected was a higher number. People tend to overestimate their fitness, and the result is usually lower than they thought.

The range I see in a 45 year old at a desk

The estimated readings I have taken so far in that group run from 31 to 43 mL/kg/min. The spread is wide, and habits explain most of it.

Two types turn up. One made peace early with being desk-bound and built training around it deliberately. The other got swallowed by work and never treated it as something that mattered.

For that second group the number lands slowly. There was sport in their twenties and a generally active life. Then the job got heavier, travel and stress stacked up, and the desk won.

They still think of themselves as the person who played sport. When we zoom out, it has often been 15 years.

The surprise is rarely the number itself. It is how long it has been.

What watches and podcasts get right, and what they miss

Less than you would think. Both have got genuinely good.

A Garmin, in my own experience, gives a solid estimate and sensible training guidance, and several people explaining this subject publicly do it well. Carrying that on your wrist is a genuine privilege of the age we live in.

What a watch cannot do is treat the number as one piece of a jigsaw. It doesn’t know your blood pressure, how you move or what your week looks like.

You could gather every one of those numbers yourself and hand them to AI. You would still be missing someone who understands the person in front of them: what you want, what makes you tick and what will actually get you to change.

What actually improves it, and how fast

For most of my clients, VO2 max improves as a by-product and is not the target.

A recent client came in at 32. Blood pressure, waist-to-hip ratio and weight all wanted attention before anything else, and the movement screen came back low.

Hard intervals are not where someone like that starts. The health markers and the movement come first. The VO2 max should follow, partly because the number is per kilo of bodyweight, and partly because regular training lifts it anyway.

The research supports that. A 2015 review of 28 controlled trials in healthy adults found that steady endurance training raised VO2 max by an average of 4.9 mL/kg/min compared with no exercise. Interval training raised it by 5.5. The gap between the two is small.

On speed: an eight-week study of moderately trained men, training three times a week, found about a 7% improvement from interval sessions. A two-year trial in sedentary adults with an average age of 53 found an 18% rise.

Expect a measurable change in about two months and a large one over years.

Who should not care about this number

Nobody. A study of more than 122,000 adults found that higher cardiorespiratory fitness was linked with a lower risk of death from any cause, with no upper limit to the benefit.

That applies to someone who doesn’t train, and to a bodybuilder who looks exceptional but has a low VO2 max.

Everyone should care about it. Nobody should obsess over it. VO2 max is an outcome, not a process.

What shifts it is turning up week after week. Sessions that fit the day you actually have, suit the body you actually have, and leave you feeling better, not worse. A hard six or twelve week push that buys one mL/kg/min and is followed by nothing at all is worth less than that.

If you want the number itself, here is what the test involves and what it costs. If you would rather start with how you move, that is the movement assessment.