The Problem With 220 Minus Your Age
220 minus age was never derived from a proper study. Tanaka's 208 minus 0.7 times age fits the data better, especially later in life.
- Maximum heart rate falls by about 0.7 beats a year, not a full beat.
- The difference is about 6 beats at 60 and 9 at 70, enough to shift which zone a heart rate falls in.
- Any age-based estimate carries roughly ±10 beats of individual variation.
Where 220 came from
The best known formula in fitness is also one of the least accurate. "220 minus age" was never derived from a proper study. It emerged from a rough fit to scattered data in the 1970s and stuck because it's easy to remember.
A better formula
Tanaka and colleagues revisited it against a meta-analysis of more than 18,000 people and found maximum heart rate actually declines by about 0.7 beats per year rather than a full beat, giving 208 minus 0.7 times age. The difference is small in your twenties and substantial later: around 6 beats at 60 and 9 at 70, easily enough to shift which training zone a given heart rate falls into. Gulati's later work found women decline differently again.
Treat zones as guidance
Worth knowing regardless of formula: any estimate based on age carries roughly ±10 beats of individual variation, so treat zones as guidance rather than precision instrumentation.
Kriterion's HIIT timer works your heart-rate zones out from a better estimate than that one, and shows you the actual BPM window rather than a percentage to do in your head.
References
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 2001.
- Gulati M, Shaw LJ, Thisted RA, Black HR, Bairey Merz CN, Arnsdorf MF. Heart rate response to exercise stress testing in asymptomatic women. Circulation, 2010.
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate: a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 1957.
Read next
Kriterion is the app this reasoning is built into
It measures your maintenance calories from what you actually ate against what the scale actually did, tells you how firmly the number is pinned down, and checks its own past predictions against your results. Free logging, UK food data, and no ads.
Join the list and you get the founding offer: the launch price, held for as long as you stay subscribed. It is capped at the first 1,000 subscribers or 90 days from launch, whichever comes first, and it will not be extended. One confirmation now, one email on launch day. Not a newsletter.