VO₂ max for midlife women may be one of the most useful fitness numbers you can understand—not because you need to chase a perfect score, but because it tells you something about how well your body delivers and uses oxygen when you move.
VO₂ Max for Midlife Women
For the longest time, I thought of fitness in very simple numbers.
How many steps did I take today?
How many kilometres did I walk?
Did I close my exercise ring?
How many minutes did I stand?
Did I complete my workout?
And then someone asked me a question I had never really considered:
“What is your VO₂ max?”
I had heard the term, but I didn’t really know what it meant. A little research opened up an entirely different way of looking at fitness—especially as we move through midlife.
Because VO₂ max isn’t simply about how much you exercise. It is about how efficiently your body can use oxygen when your heart and muscles are working hard.
And that makes it a fascinating measure of cardiovascular fitness.
So, what exactly is VO₂ max?
VO₂ max stands for maximal oxygen uptake.
In simple language, imagine oxygen as fuel being delivered to your body.
When you exercise, your lungs take in oxygen. Your heart pumps oxygen-rich blood around your body. Your blood vessels deliver it to your working muscles, and your muscles use that oxygen to produce energy.
VO₂ max is essentially a measure of how much oxygen your body can use during intense exercise.
It is expressed as:
millilitres of oxygen per kilogram of body weight per minute (mL/kg/min).
The higher your cardiorespiratory fitness, generally, the more efficiently this entire system can work.
That is why the American Heart Association has described cardiorespiratory fitness as an important indicator of overall physiological health. Research has also consistently found an inverse relationship between cardiorespiratory fitness and mortality risk.
Why should a midlife woman care about it?
Because midlife is a period when maintaining fitness becomes increasingly important.
Ageing naturally brings a decline in VO₂ max. At the same time, becoming less active can accelerate the decline in cardiorespiratory fitness.
Research specifically examining midlife and older women shows that regular endurance exercise can substantially preserve cardiorespiratory fitness and cardiovascular function. Women who have maintained structured endurance exercise over the years can have fitness levels comparable with, or even better than, much younger sedentary women.
And this is important because cardiovascular health isn’t something we should suddenly start worrying about when we are older.
Midlife is an opportunity to build the physiological reserve that we want to carry into later life.
Think of VO₂ max as one piece of that reserve.
But is 23–35 the “perfect” VO₂ max for every midlife woman?
Not exactly.
You may see numbers such as 23–35 mL/kg/min described online as desirable for women in midlife. But there isn’t one universal VO₂ max number that defines “optimal heart health” for every woman.
VO₂ max changes with age and sex, and reference ranges differ according to the population and testing method.
For example, Apple Watch doesn’t diagnose cardiovascular health from VO₂ max. It provides an estimate of cardio fitness, using information such as age, sex, height and weight and measurements collected during outdoor walking, running or hiking.
So rather than obsessing over whether your number is exactly 23, 30 or 35, a more useful question is:
Is my cardiorespiratory fitness appropriate for my age, and am I maintaining or improving it over time?
And if your number is currently low, that isn’t a verdict.
It is information.
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Your steps don’t tell the whole story
This was probably the biggest revelation for me.
You can walk 8,000 or 10,000 steps a day and still need to work on cardiovascular fitness.
Steps tell us about movement volume.
VO₂ max tells us something different: how well your cardiorespiratory system performs when challenged.
Standing regularly is valuable. Walking is valuable. Daily movement is valuable.
But your cardiovascular system also benefits from periods where your heart rate rises sufficiently to create a training stimulus.
That doesn’t mean every workout needs to be exhausting.
It means that fitness requires some intentional cardiovascular challenge, not only accumulated daily movement.
What can improve VO₂ max?
The encouraging part is that VO₂ max is not fixed.
It can improve with appropriate cardiovascular training. Apple itself notes that increasing the intensity and frequency of cardiovascular exercise can improve VO₂ max.
There are several ways to work towards it.
1. Brisk walking
Never underestimate walking.
A comfortable stroll is wonderful for movement, but deliberately increasing your pace so that you’re breathing harder creates a different stimulus.
You can also introduce hills or inclines.
For someone starting out, simply progressing from comfortable walking to brisk walking can be a meaningful step.
2. Intervals
You don’t have to run.
You can alternate periods of higher effort with easier recovery.
For example:
2 minutes brisk → 2 minutes easy → repeat.
As fitness improves, the harder intervals can gradually become longer.
Intervals are useful because they allow you to accumulate time at a higher intensity without having to sustain that intensity continuously.
3. Cycling
Cycling is another excellent cardiovascular activity.
You can vary resistance and speed to create different levels of challenge.
It also gives you an option if walking or running is uncomfortable for your joints.
4. Rowing
Rowing can provide a demanding whole-body cardiovascular workout.
Because it involves the legs, back and upper body, it can raise your heart rate considerably when performed with appropriate technique.
5. Aerobic dance and Zumba
Yes—something enjoyable counts.
Dance-based exercise can provide substantial cardiovascular stimulus, particularly when the class includes sustained periods of moderate-to-vigorous movement.
The important thing isn’t the name of the exercise.
The important thing is the cardiovascular demand it creates.
6. Strength training still matters
This is where many people make the mistake of thinking that VO₂ max means “do more cardio and forget everything else.”
Don’t.
Midlife fitness needs a broader foundation.
Strength training helps maintain muscle mass, strength, physical function and metabolic health. Cardio and strength training complement each other rather than competing with each other.
A strong body that can also sustain aerobic activity is a much more useful goal than simply chasing one number.
What might you be doing wrong?
Perhaps nothing.
But there are a few common traps.
Only counting steps: 10,000 steps don’t automatically mean excellent cardiorespiratory fitness.
Doing every workout at the same easy intensity: your body adapts to what you repeatedly ask it to do. Some progressive challenge is useful.
Doing only cardio: strength matters enormously as we age.
Doing only strength training: resistance training is essential, but it doesn’t replace cardiovascular conditioning.
Expecting rapid changes: fitness adaptations take time.
Chasing the watch number: wearable estimates are useful for observing trends, but they aren’t the same as a laboratory VO₂ max test. Apple specifically describes its measurement as an estimate of cardio fitness.
And perhaps the biggest mistake is thinking that a single number defines your health.
It doesn’t.
The goal isn’t to become an athlete
This is something I find particularly reassuring.
The research doesn’t say that every midlife woman needs to become a runner or train like an endurance athlete.
In fact, research in women shows a clear gradient: better cardiorespiratory fitness is associated with lower mortality risk, with particularly meaningful differences among women at the lower end of the fitness spectrum.
That means the person who moves from low fitness to moderate fitness may have much more to gain than someone already highly trained who is trying to squeeze out another tiny improvement.
So if your VO₂ max is currently 20, don’t look at someone else’s 35 and feel defeated.
Your first goal might simply be 20 → 22 → 24.
Progress matters.
What I am taking away from this
I started by thinking fitness was about completing my rings, accumulating steps and watching the distance on my Apple Watch.
Now I see it differently.
I want to know not only how much I move, but also how well my body responds when I move.
I want to maintain muscle.
I want to keep my heart and lungs challenged.
I want to be able to climb stairs without feeling defeated by them.
I want to walk briskly, dance, cycle, row, lift weights and still have the physical capacity to enjoy life as I get older.
And perhaps that is the real lesson of VO₂ max.
It isn’t a number to fear. It is a capacity to build.
For a midlife woman, fitness isn’t about trying to look younger.
It is about making sure your body remains capable, resilient and independent for as many years as possible.
So perhaps the next time you check your steps, distance or exercise minutes, take a look at your cardio fitness too.
Not to judge yourself.
Just to know where you are—and where you can go from here.
You may like to read: Releasing Old Mindsets: Mindset Shifts to Overcome Midlife Loneliness
Note: VO₂ max is an important measure of cardiorespiratory fitness, but it is not a standalone diagnosis of heart health. If you have cardiovascular symptoms, significant medical conditions, or are starting vigorous exercise after a long period of inactivity, discuss an appropriate exercise plan with your healthcare professional.
Related: Women 40+: How to Structure Your Week for Strength, Energy & Longevity
