Fitness Age Calculator: VO2 Max Estimate

Find your fitness age in under a minute, with no treadmill test. Enter your age and resting heart rate to get an estimated VO2 max, the age your fitness matches, and how you rank against men your age in a large US fitness registry.

Built for men. The heart rate method used here was developed and tested in men. Women can use the NTNU fitness calculator, which was built from data on both men and women.

Sit or lie quietly for about 10 minutes, then count your pulse for 30 seconds and double it. Your watch’s resting heart rate also works.

Leave blank and we will estimate it from your age.

Your fitness age
0
0your real age
0your fitness age
0estimated VO2 max (ml/kg/min)
–percentile for your age
0max heart rate used

How your VO2 max compares

Percentile VO2 max (ml/kg/min) Band
This is a rough estimate. The heart rate ratio method was developed and tested in well-trained men, and using an age-estimated max heart rate adds more error. Treat results for less active and older men as a rough guide. A lab treadmill test is the only way to measure VO2 max directly.
Heart rate medicines change these numbers. Beta-blockers and some other medicines lower your heart rate, which makes this estimate unreliable. If you take heart medication, have a heart condition, or feel chest pain, dizziness or unusual breathlessness when you exercise, see your doctor before training hard.

How the fitness age calculator works

Step 1: estimate VO2 max. VO2 max is the most oxygen your body can use during hard exercise, and it is one of the strongest markers of long-term health. This calculator uses the heart rate ratio method of Uth and colleagues (2004): VO2 max ≈ 15.3 × (max heart rate ÷ resting heart rate). A fitter heart pumps more blood per beat, so your resting heart rate falls while your max heart rate stays roughly the same. If you do not enter a tested max heart rate, we estimate it with the Tanaka formula (208 − 0.7 × age).

Step 2: find your fitness age. The idea of “fitness age” was popularised by the fitness research group at the Norwegian University of Science and Technology (NTNU), whose online calculator uses a questionnaire model from the HUNT study. We use the simpler heart rate method instead, and define your fitness age as the age at which a typical man (the 50th percentile) has the VO2 max we estimated for you. For the typical values we use the FRIEND registry reference standards (Kaminsky et al., 2022): more than 16,000 treadmill tests of apparently healthy US adults aged 20 to 89. Each decade’s median is placed at the middle of that decade, and ages in between are interpolated. The percentile shown compares you with men in your own age decade.

How to lower your fitness age

VO2 max responds to training at any age. The simplest plan: build a base of easy zone 2 cardio (2–3 sessions a week where you can still talk), then add one session of hard intervals, such as 4 rounds of 4 minutes hard with 3 minutes easy in between. Re-check every 8–12 weeks, measuring your resting heart rate the same way each time. Read the full guides: how to raise your VO2 max after 35, zone 2 training for men over 35 and heart health after 35.

Sources

  1. Uth N, Sørensen H, Overgaard K, et al. (2004). Estimation of VO2max from the ratio between HRmax and HRrest: the heart rate ratio method. European Journal of Applied Physiology 91:111–115
  2. Mayo Clinic: heart rate, what is normal? (adult resting heart rate 60 to 100 bpm)
  3. Tanaka H, Monahan KD, Seals DR (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology
  4. Kaminsky LA, et al. (2022). Updated reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the FRIEND registry. Mayo Clinic Proceedings
  5. NTNU Cardiac Exercise Research Group (CERG): fitness calculator and fitness age research

This calculator gives general education, not medical advice. It cannot diagnose any condition. Check with your doctor before starting hard exercise, especially if you have a heart condition or take medication.

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