How it works
VO2 max, the most oxygen your body can use during hard exercise, is one of the best single measures of heart and lung fitness. Measuring it takes a lab and a treadmill test to exhaustion. Researchers in Norway's HUNT Fitness Study tested thousands of healthy adults and built a formula that estimates it from simple questions instead.
The estimate
This tool uses the HUNT non-exercise model with BMI (Nes et al., Medicine & Science in Sports & Exercise, 2014): age, BMI, resting heart rate and a physical activity score from how often, how long and how hard you exercise.
- Men: 92.05 - 0.327 x age - 0.933 x BMI - 0.167 x resting HR + 0.257 x activity score
- Women: 70.77 - 0.244 x age - 0.749 x BMI - 0.107 x resting HR + 0.213 x activity score
The activity score multiplies points for frequency (0-3), duration (1 or 1.5) and intensity (0, 5 or 10), so it runs from 0 to 45.
Fitness age
Your fitness age is the age at which the average person of your sex has your estimated VO2 max, using the HUNT age trend (men 63.6 - 0.393 x age, women 51.6 - 0.328 x age). Those lines match NTNU's published averages for each age group.
How accurate is it?
In the study the estimate was typically within about 6 mL/kg/min of a real lab test, so treat your fitness age as a rough guide. The best way to move it is regular exercise that gets you breathing hard. For the researchers' own calculator, visit NTNU's CERG site.
