Longevity

VO2 max: the fitness number that predicts survival

VO2 max is the most oxygen your body can use in 1 minute, in millilitres per kilogram of body weight, and it is the single fitness figure most closely tied to how long you live. In 122,007 adults followed for a median of 8.4 years, those in the lowest fitness quarter for their age and sex had 5 times the adjusted death rate of the fittest 2.3%, a wider gap than smoking (1.41) or diabetes (1.40) produced. A healthy person in their 50s measures about 43 ml/kg/min if male and 34 if female, the value falls by roughly 3.5 ml/kg/min a decade, and each 3.5 ml/kg/min (1 MET) kept or regained is linked to 11% to 17% lower all-cause mortality.

What VO2 max measures

VO2 max is the largest amount of oxygen your body can take in, transport and use in 1 minute of all-out effort, written in millilitres per kilogram of body weight per minute (ml/kg/min). Clinics often report the same capacity in METs, metabolic equivalents: 1 MET is the oxygen you use sitting still, defined as 3.5 ml/kg/min, so 10 METs equals a VO2 max of 35.

The reference measurement is a graded treadmill or bicycle test with a mask that analyses every breath until you cannot continue. Many people stop before the physiological plateau: in the Norwegian Generation 100 trial, 41% of participants aged 70 to 77 did not meet the criteria for a true maximum, so the researchers reported peak oxygen uptake instead. Most survival evidence rests on estimates rather than masks: hospital cohorts derive METs from treadmill speed and gradient, sports watches use heart rate and pace, and non-exercise calculators use age, waist size, resting heart rate and self-reported activity. Estimates track your own trend; they are less reliable against a reference table.

What a good value is at your age

The largest European reference set is the HUNT 3 Fitness Study in Norway, published in PLoS One in 2013: 1,929 healthy men and 1,881 healthy women aged 20 to 90 ran to exhaustion on a treadmill while their breath was analysed. Mean VO2 max was 45.4 ml/kg/min in men and 37.0 in women. At 20 to 29 it was 54.4 for men and 43.0 for women; at 70 and over, 35.3 and 28.3. The value fell by roughly 3.5 ml/kg/min, about 1 MET, per decade, and maximal heart rate by about 6 beats a minute, from 196 in men and 194 in women in their 20s.

Read the table below as an average from an active Scandinavian population, not a pass mark: the authors note that most other populations are more sedentary than Norwegians, so a value on the HUNT average is probably above average elsewhere. They also flag the range that earlier studies linked to higher mortality and cardiovascular events, below 8 METs (28 ml/kg/min) for men and 6 METs (21 ml/kg/min) for women. Only 25 men and 9 women over 50 fell into it, but the share rose with age, from 1% of men aged 50 to 59 to 4% in their 60s and 11% at 70 and over, with women at about half those proportions. Two cautions: laboratory values run higher than watch or treadmill estimates, and because the figure is per kilogram, losing fat raises it without any change in the heart.

How strongly it predicts survival

The clearest single dataset is a 2018 study in JAMA Network Open of 122,007 adults who had a symptom-limited treadmill test at one US academic medical centre between 1991 and 2014. Median age was 53.4 years and 40.8% were women. Fitness was estimated in METs and each patient ranked against others of the same age and sex: low (below the 25th percentile, mean 6.1 METs), below average (25th to 49th, 8.2), above average (50th to 74th, 9.6), high (75th to 97.6th, 11.4) and elite (97.7th and above, 13.8). Over a median 8.4 years and 1.1 million person-years, 13,637 patients (11.2%) died.

After adjustment for age, sex and clinical risk factors, low fitness carried a hazard ratio of 5.04 (4.10 to 6.20) against elite fitness. Being below average rather than above average raised risk by 41% (HR 1.41), as much as smoking (1.41) or diabetes (1.40) and more than coronary artery disease (1.29). There was no ceiling: the elite group, 2 standard deviations or more above the mean, still had 23% lower mortality than the high group (HR 0.77, 0.63 to 0.95), and the gap held in patients aged 70 or over (0.71) and with hypertension (0.70).

A 2024 overview in the British Journal of Sports Medicine gathered 26 systematic reviews representing 199 cohort studies and more than 20.9 million observations. High against low fitness meant 53% lower all-cause mortality (HR 0.47, 0.39 to 0.56) and 69% less new heart failure (0.31). Each 1 MET more, a step of 3.5 ml/kg/min, was associated with 11% to 17% lower all-cause mortality and 18% lower heart failure risk. The reviewers graded the certainty as very low to moderate, as all of it comes from observational cohorts.

How much training moves the number

The WHO recommends at least 150 minutes of moderate-intensity activity a week for adults; its 2020 guideline sets the band at 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity, plus muscle-strengthening work on 2 or more days. Its fact sheet of 26 June 2024 reports that 31% of adults worldwide, 1.8 billion people, miss even the minimum, and that they carry a 20% to 30% higher risk of death.

Whether VO2 max still responds in later life was tested by the Generation 100 trial, published in the BMJ in 2020. In Trondheim, 1,567 people aged 70 to 77 (790 women) were randomised for 5 years to 2 weekly interval sessions (400 people: a 10 minute warm-up, then 4 times 4 minutes at about 90% of peak heart rate), 2 weekly sessions of 50 minutes of continuous work at about 70% (387 people), or the national advice of 30 minutes of moderate activity almost every day (780 controls). Baseline peak oxygen uptake was 28.6 to 28.9 ml/kg/min, and a fall of at least 3.5 ml/kg/min was expected over the 5 years. None of the groups declined. The training groups combined were 0.8 ml/kg/min above the controls after 1 year, 0.7 after 3 and 0.3 after 5, and the interval group ended 0.7 above both other groups.

Mortality after 5 years was 4.6% overall: 4.7% in the controls, 5.9% with continuous training and 3.0% with intervals. The interval group's hazard ratio against controls was 0.63, but the confidence interval (0.33 to 1.20) crossed 1, so the trial does not prove that intervals extend life; the controls also did much of their own activity at high intensity. What it shows is that 2 hard sessions a week can hold VO2 peak steady at 70 to 77. The Heart Rate Zones tool gives you the 70% and 90% marks, and strength training after 40 covers the 2 days of muscle work the WHO adds.

What the numbers cannot tell you

Every survival figure above is an association. The 122,007 patients were referred for testing because of symptoms or risk, at a single centre, with fitness estimated once rather than measured, and the authors could not adjust for socioeconomic status or ethnicity. Fit people also differ in diet, smoking history, weight and income, and adjustment removes only part of that. What the studies establish is consistency: in every age band, in both sexes and across 199 cohorts, higher fitness went with fewer deaths, and the gradient held at the top.

The reference values have limits. The HUNT sample is Norwegian and more active than most populations, so a value that reads as below average there may be average in your country, and the Generation 100 trial recruited people who were already well, 87.5% reporting good health and 80% medium or high activity. Two cheaper markers, grip strength and walking speed, predict independence along similar lines, and healthspan versus lifespan puts all three in context.

Speak to a doctor before testing or training hard if you have heart disease, chest pain or breathlessness on exertion, uncontrolled high blood pressure, diabetes treated with insulin or other glucose-lowering drugs, kidney disease, or if you are pregnant or under 18. A beta blocker lowers your peak heart rate, so percentages of peak do not apply and perceived exertion is the better guide. A supervised test with gas analysis is the safest way to learn your real number and your safe training range.

Ways to raise or protect your VO2 max

Frequently asked

What is a good VO2 max for my age?

In 3,816 healthy Norwegians tested on a treadmill, the mean was 54.4 ml/kg/min for men and 43.0 for women in their 20s, 42.6 and 34.4 in their 50s, and 35.3 and 28.3 at 70 and over. Values below 28 for men and 21 for women are the range that earlier studies linked to higher mortality.

Is VO2 max really a stronger predictor than smoking?

In 122,007 adults followed for a median of 8.4 years, low fitness carried an adjusted hazard ratio of 5.04 against elite fitness, and being below rather than above average raised risk by 41%, the same as smoking (1.41) and more than diabetes (1.40). These are associations from a referred hospital population, not proof of cause.

Can I still raise VO2 max after 70?

You can at least hold it. In the 5-year Generation 100 trial, 1,567 people aged 70 to 77 who trained twice a week showed no decline in peak oxygen uptake, although a fall of at least 3.5 ml/kg/min was expected, and the interval group finished 0.7 ml/kg/min above the control and moderate groups.

Is there a point where more fitness stops helping?

Not in the data so far. The fittest 2.3% of 122,007 patients had 23% lower mortality than the next group (hazard ratio 0.77), and the advantage held in people aged 70 or over (0.71) and in those with hypertension (0.70).

How accurate is the VO2 max on my sports watch?

It is an estimate from heart rate and pace, not a measurement, and it will differ from a laboratory test with breath analysis. Use it to follow your own trend over months rather than to compare yourself with reference tables, and ask for a supervised test if the exact figure matters for a medical decision.

What does 1 MET mean?

One MET is the oxygen your body uses at rest, defined as 3.5 ml/kg/min, so a VO2 max of 35 equals 10 METs. In pooled cohort data each extra MET of fitness was associated with 11% to 17% lower all-cause mortality and 18% lower risk of heart failure.

Sources

• Mandsager et al. 2018, JAMA Network Open: Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing · 122,007 patients tested 1991 to 2014 at one US academic medical centre, median age 53.4, 40.8% women, 43.7% hypertension, 15.7% coronary artery disease; median follow-up 8.4 years, 1.1 million person-years, 13,637 deaths (11.2%); groups by age- and sex-matched percentile with mean METs 6.1, 8.2, 9.6, 11.4 and 13.8; low vs elite HR 5.04 (4.10 to 6.20), elite vs low 0.20, elite vs high 0.77 (0.63 to 0.95), below vs above average 1.41; smoking 1.41, diabetes 1.40, coronary disease 1.29; age 70 or over 0.71, hypertension 0.70; no observed upper limit of benefit. Open access copy on PubMed Central
• Lang et al. 2024, British Journal of Sports Medicine: Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults, an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies · Searches January 2002 to March 2024, 26 systematic reviews included; high vs low fitness all-cause mortality HR 0.47 (0.39 to 0.56); per 1 MET 11% to 17% lower all-cause mortality (HR 0.89 and 0.83); incident heart failure HR 0.31 high vs low and 0.82 per MET; cardiovascular mortality in people with cardiovascular disease HR 0.27; GRADE certainty very low to moderate. Open access copy on PubMed Central
• Loe et al. 2013, PLoS One: Aerobic capacity reference data in 3816 healthy men and women 20 to 90 years, the HUNT 3 Fitness Study · 1,929 men and 1,881 women, treadmill running with breath-by-breath gas analysis; mean VO2 max 45.4 (men) and 37.0 (women) ml/kg/min, mean age 46.7; by decade men 54.4, 49.1, 47.2, 42.6, 39.2, 35.3 and women 43.0, 40.0, 38.4, 34.4, 31.1, 28.3; decline about 3.5 ml/kg/min and 6 beats a minute per decade; risk range below 8 METs (28) for men and 6 METs (21) for women, 25 men and 9 women over 50 in it, 1%, 4% and 11% of men by decade from 50; authors note Norwegians are more active than most populations
• Stensvold et al. 2020, BMJ: Effect of exercise training for five years on all cause mortality in older adults, the Generation 100 study, randomised controlled trial · 1,567 of 6,966 invited people born 1936 to 1942 in Trondheim, mean age 72.8, 790 women; HIIT n=400 (10 minute warm-up, 4 times 4 minutes at about 90% of peak heart rate, twice a week), MICT n=387 (50 minutes at about 70%), control n=780 following national guidelines of 30 minutes most days; 41% did not meet criteria for a true maximum; baseline peak oxygen uptake 28.6 to 28.9 ml/kg/min; expected decline at least 3.5 ml/kg/min over 5 years, none observed; combined training groups 0.8, 0.7 and 0.3 ml/kg/min above control at 1, 3 and 5 years, HIIT 0.7 above control and MICT at 5 years; supervised intensity 90% and 72% of peak heart rate; mortality 4.6% overall, 4.7% control, 5.9% MICT, 3.0% HIIT, HIIT vs control HR 0.63 (0.33 to 1.20); 87.5% reported good health and 80% medium or high activity at baseline. Open access copy on PubMed Central
• WHO fact sheet, 26 June 2024: Physical activity · At least 150 minutes of moderate-intensity activity a week; 31% of adults, 1.8 billion people, physically inactive in 2022, up 5 percentage points since 2010, projected 35% by 2030; insufficiently active people have a 20% to 30% higher risk of death. The 150 to 300 minute band, the 75 to 150 minutes of vigorous activity and the 2 or more days of muscle strengthening are from the 2020 WHO guidelines on physical activity and sedentary behaviour

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This guide is for general information. It does not replace medical advice or an examination.