The rule of thumb says about 1 percent a year. It does not hold. In the Baltimore Longitudinal Study of Aging, the decline accelerated from 3 to 6 percent per ten years in people in their twenties and thirties to more than 20 percent per ten years above seventy (PMID 16043637).
So you do not lose the same slice every year. You lose it faster and faster.
That is the most underrated health figure I know, and it appears on none of the pages about VO2max.
How much does your VO2max fall per ten years?
It depends heavily on your age. Fleg and colleagues followed 435 men and 375 women aged 21 to 87, with repeated treadmill tests over a median of nearly eight years. Peak uptake fell in every decade, but the rate rose with each one (PMID 16043637).
The table sets the rule of thumb against the measured reality.
| Age group | What the rule of thumb says | What the long-running study showed |
|---|---|---|
| 20 to 39 years | about 10 percent per 10 years | 3 to 6 percent per 10 years |
| 40 to 69 years | about 10 percent per 10 years | rising per decade, faster in men |
| 70 years and over | about 10 percent per 10 years | more than 20 percent per 10 years |
So the rule of thumb is too gloomy when you are thirty and far too cheerful when you are seventy-five.
It is that second error that leaves most people unprepared.
Why do the usual tables look too optimistic?
Because they come from cross-sections. There you test different people of different ages on a single day and draw a line through the results. The problem: the eighty-year-olds who show up in a test lab are a select group, because their least fit peers are gone or do not come.
That flattens the curve artificially.
Follow the same people through time, as Baltimore did, and the bias disappears. The curve steepens, and the acceleration appears. That is the core of why this study counted as news in 2005.
What counts as a good value for your age still sits in the norm tables in what is a good VO2max. Read them as a snapshot, not as a forecast of your own next ten years.
Why does it fall faster in men after forty?
In this study the decline per decade from the forties onward was larger in men than in women. Men start higher on average, so there is more to lose. On top of that, the oxygen pulse, the amount of oxygen you use per heartbeat, fell at the same rate as peak uptake itself.
Your heart rate was not the culprit here.
Maximum heart rate dropped only 4 to 6 percent per ten years, and that decline barely accelerated (PMID 16043637). What did move was how much blood your heart shifts per beat and how much oxygen your muscles pull from it.
That shifts attention from your heart-rate monitor to your muscles and your blood. Muscle mass is part of that story, and it sits in sarcopenia and muscle loss after 40.
How much do you train back?
Enough to move years, not enough to flatten the curve. In the Baltimore group the acceleration showed up across all activity levels, including in people who reported themselves as active. Training moves your position on the curve upward; it barely changes its shape.
That sounds bleak and is not.
Helgerud and colleagues saw 7.2 percent of gain in trained men over eight weeks with four-times-four-minute intervals (PMID 17414804). Set that against a loss of 5 percent per decade and you see what one good training block is worth in practice: roughly ten years of natural decline, in two months.
Imagine a man of 55 sitting at 34 ml/kg/min. A successful eight-week block puts him around 36, which is roughly where he stood ten years earlier.
That is not a promise for everyone. It is a good argument for not skipping the intervals.
The protocol sits in increasing your VO2max. The Dutch Gezondheidsraad also holds 150 minutes of moderately intensive activity per week, plus muscle-strengthening work twice a week.
Why does this matter outside sport?
Because below your aerobic capacity sits a line under which everyday things turn heavy. Climbing stairs, carrying shopping and catching a bus each cost a fixed number of millilitres of oxygen. Drop your maximum, and the same chore eats a larger share of it.
The researchers named that explicitly as the reason the acceleration matters.
The American Heart Association called fitness a clinical vital sign in 2016, because low fitness is associated with a higher risk of cardiovascular disease and mortality (PMID 27881567). Mandsager and colleagues saw in a group of 122,007 people that higher fitness was associated with lower mortality, with no clear ceiling (PMID 30646252).
Those are associations in large groups, not a prediction for you.
Which blood values move along with the years?
A few values can deepen the decline without you noticing it in training. Thyroid hormone drives your metabolism and your heart-rate response. Iron stores drop away quietly more often in older athletes. Low-grade inflammation rises with the years and is associated with poorer recovery.
None of those values explains the age curve itself.
They do decide whether your curve runs above or below your peers, and that is the part you can act on. How that chain works sits in cardio fitness and your blood.
Which values matter more broadly as you age sits in healthy ageing as an athlete.
What do you do with this?
Record one fixed measurement a year and keep the series. Your annual figure says little; your five-year line says everything, because it shows whether you sit on the average curve or come out under it. How to record that measurement reliably sits in measuring your VO2max.
My suggestion: take that measurement in the same month every year, because summer skews your result.
If you want the blood side alongside it, thyroid, iron, haemoglobin and inflammation markers sit together in the Whoop panel.
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
References
- Fleg JL, Morrell CH, Bos AG, et al. Accelerated longitudinal decline of aerobic capacity in healthy older adults. Circulation, 2005;112(5):674-82. PMID 16043637.
- Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Network Open, 2018;1(6):e183605. PMID 30646252.
- Ross R, Blair SN, Arena R, et al. Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign. Circulation, 2016;134(24):e653-e699. PMID 27881567.
- Helgerud J, Hoydal K, Wang E, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine and Science in Sports and Exercise, 2007;39(4):665-71. PMID 17414804.
- Gezondheidsraad. Physical activity guidelines.
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