The guide

What's the minimum VO2 max you want?

By GyroscopeUpdated November 15, 20269 sources

The bare floor is about 18 ml/kg/min for men and 15 for women. Below it, living on your own gets hard. But at 18, carrying the groceries upstairs takes everything you have, so the minimum to want is higher. Stay out of the bottom quarter for your age, keep everyday things well under your max, and aim for the top half of your decade.

Isn’t there one number everyone should hit?

People want a magic number, the way 120 over 80 works for blood pressure. You’ll see “aim for 35” or “40 is good” on fitness forums, and both are fine for some people and silly for others. 35 is the middle for a man in his 40s and the top 10 percent for a woman in her 60s.

A better question is what your number has to carry. Your VO2 max is a ceiling, and the tasks in your day are the weight you lift up to it. A number is enough when the ordinary things sit well under it, with room to spare as the years take some away.

What does each number let you do?

Everything you do costs oxygen, and scientists have measured how much. The 2024 Adult Compendium of Physical Activities lists the cost of more than 1,100 activities in METs, multiples of what you burn sitting still, where 1 MET is 3.5 ml/kg/min. Multiply by 3.5 and you can put any task on the same scale as your VO2 max.

Slide your number and watch the shares change. At a VO2 max of 20, carrying groceries upstairs takes 93 percent of it and normal-pace stairs are past it. At 30 the groceries take 62 percent and the stairs 79. At 40 they’re down to 46 and 60.

Think of a small car on the highway. It can reach 65 mph, so on paper it’s fine. But every hill needs the pedal on the floor, and passing a truck is out of the question. A bigger engine doesn’t go faster on the flat. It just has room left over when the road tilts up.

The three lines to know

The independence line. The physiologist R. J. Shephard reviewed what falling fitness means in old age and concluded that loss of independence seems likely once VO2 max falls below about 18 for men and 15 for women, usually at 80 to 85. On the US FRIEND chart, the middle for people in their 80s is 17.6 for men and 15.4 for women, which puts about half of them at or below it. Apple uses the same two numbers for its low cardio fitness alert from age 60.

The risk line. In the Cleveland Clinic study of 122,007 adults sent for a treadmill test, people were grouped by fitness for their age and sex and followed for a median of 8.4 years. The bottom quarter, the low group, had the highest risk of death, 5.04 times that of the fittest 2 percent. Below average against above average was 1.41, the same as smoking in that study. For people under 60, Apple’s alert uses the lowest fifth for their age and sex. It’s an observational study in people sent for a stress test, so it shows a link, and why it predicts how long you live has what that does and doesn’t mean.

The daily-life line. This one is yours. List the hardest things you want to keep doing (stairs at work, a hike with your kids, singles tennis at 70) and look up their cost on the ladder. If they sit near the top of your max, you’ll feel it in every one of them.

The floors for your age

From the FRIEND 2022 treadmill table, in ml/kg/min. The bottom quarter ends at the 25th percentile, by straight lines between the published deciles.

Why the share of your max is what you feel

VO2 max is the most oxygen you can take in and use in a minute. Below it, your body can supply the oxygen a task needs as fast as it uses it, so you can keep going. Past it, the extra comes from energy your muscles can only make without oxygen for a short time, and the physiologists David Bassett and Edward Howley put the rule plainly in 2000: nobody can work above 100 percent of their VO2 max for long. That’s why a sprint up the stairs ends in a gasp while a steady climb doesn’t.

The same flight of stairs is a different job for different people. With plenty of room above it, it’s a non-event. With little room, it’s a hard effort, and with none, it’s a burst you pay for at the top.

The years count as much as the number

VO2 max falls faster each decade, from 3 to 6 percent a decade in your 20s and 30s to more than 20 percent a decade in your 70s, in healthy adults at every level of activity (Fleg 2005). A cushion of 5 points at 75 could be gone in a decade at that pace.

That’s why we’d rather you build the cushion early and protect it. Shephard found regular aerobic exercise can take 10 or more years off your biological age, and possibly keep you independent about that much longer. In Norway’s Generation 100 trial, 1,567 people aged 70 to 77 trained twice a week for five years and didn’t lose fitness at all, against an expected drop of 3.5 points. Why VO2 max falls with age has the rest of that story.

What to do with your number

1. Get a number you trust. A watch is rough, so check it with a test you run yourself or the true VO2 max quiz.
2. Put it on the ladder and on the chart for your age. If you’re under the middle, the gap is usually a few months of training.
3. Build the two layers. Steady cardio most days and one or two hard sessions a week. How to raise it has the plan.
4. Keep the muscle too. Carrying things upstairs needs strong legs as well as oxygen, and strength.guide covers keeping them as you age.

If your number is near the independence line already, or you have a heart condition, read before you go hard and start with walking. A brisk walk is about 4.8 METs on the ladder, a real workout at that end of the scale, and exercise.guide explains how fast brisk is.