For decades, doctors have tracked cholesterol, blood pressure and body weight to gauge who is on course for a long life. A different marker is claiming more of that space. It is called VO2 max, and it captures the peak rate at which your body pulls in and uses oxygen during hard exertion.
A Cleveland Clinic analysis of 122,007 adults published in JAMA Network Open in October 2018 found that the least fit participants had roughly five times the risk of dying over the follow-up compared with the most fit. Median follow-up was 8.4 years. The size of that gap was larger than the mortality signal tied to smoking, diabetes or established coronary artery disease in the same dataset.
Why fitness is being called a vital sign
VO2 max is measured in milliliters of oxygen consumed per kilogram of body weight per minute. It reflects how well the heart, lungs and working muscles cooperate. The higher the number, the more oxygen your body can move into tissue that needs it.
A 2016 scientific statement from the American Heart Association, led by Queen's University professor Robert Ross, called cardiorespiratory fitness a potentially stronger predictor of mortality than smoking, hypertension, high cholesterol or type 2 diabetes. The panel urged clinicians to measure or estimate fitness in every adult at least once a year, treating it alongside pulse and blood pressure as a routine check.
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Unlike cholesterol, VO2 max responds fast to training. Cleveland Clinic exercise physiologists say a sedentary beginner can realistically gain 10 to 15 percent within a few months of consistent aerobic work.
The 122,007-patient signal
In the Cleveland Clinic dataset, participants completed a treadmill stress test and were sorted into fitness bands. The elite group averaged 13.8 metabolic equivalents, or METs, a unit that scales oxygen use against a resting baseline. The low-fitness group averaged 6.1 METs. Compared with elite performers, low-fit patients had an adjusted hazard ratio of 5.04 for death from any cause.
Cardiologist Wael Jaber, a study author at the Cleveland Clinic, told reporters that the survival curve kept improving with fitness. "We found that there was no ceiling for benefit," he said, describing the pattern as "almost a dose effect, with no toxicity at the higher end."
Reduced fitness carried a mortality signal comparable to or larger than coronary artery disease (hazard ratio 1.29), smoking (1.41) and diabetes (1.40) in the same analysis. In a Cleveland Clinic write-up, Jaber added that "extremely high aerobic fitness was associated with the greatest survival and that this benefit extended to individuals aged 70 or older and to people with hypertension."
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Two tests you can do without a lab
A precise VO2 max reading needs a mask, a treadmill and a sports medicine lab. Home estimates get close. The Cooper 12-minute run test, published by American physician Kenneth Cooper in 1968, asks you to cover as much ground as you can on a flat track in 12 minutes. Distance in kilometers slots into a formula. VO2 max equals 22.351 multiplied by kilometers, minus 11.288. Somebody who runs 2.4 kilometers scores around 42. Somebody who covers 2.8 kilometers scores around 51.
For untrained adults, a walking version is safer than an all-out run. The Rockport one-mile walk uses your finish time and post-walk pulse to estimate aerobic capacity and is used across clinical fitness assessments.
VO2 max declines with age. Typical midrange values in ml/kg/min for adults are shown below.
Age Also read: Taking ibuprofen? These habits could quietly damage your stomach and kidneys | Men (average) | Women (average) |
|---|---|---|
20-29 | 42-46 Also read: Sleeping at the same time every night may matter more than hitting 8 hours | 38-41 |
30-39 | 40-42 | 35-38 Also read: How eating kefir every day can affect your gut, blood pressure and immunity |
40-49 | 35-38 | 31-33 |
50-59 | 32-35 | 28-30 |
60+ | 26-31 | 22-27 |
How to move the number
Steady aerobic work at a pace where you can still speak in short sentences, often called zone 2, widens the network of small blood vessels feeding your muscles. Short, hard intervals raise the heart's stroke volume. A common weekly template pairs three or four zone 2 sessions of 30 to 60 minutes with one interval workout of four rounds of four minutes near maximum effort.
Talk with your doctor before starting or intensifying training if you have heart disease, uncontrolled blood pressure or symptoms during exertion.
This article is made and published by Jesper Bengtson, who may have used AI in the preparation.