Why We Don't Use "220 Minus Age"

If you have ever been told your maximum heart rate, the number almost certainly came from 220 − age. It is the most widely repeated formula in fitness, and it is not the one we use.

The two formulas

Traditional:  HRmax = 220 − age
Tanaka:       HRmax = 208 − (0.7 × age)

We use Tanaka, from Tanaka, Monahan and Seals, "Age-predicted maximal heart rate revisited", published in the Journal of the American College of Cardiology in 2001. As the title suggests, the paper exists specifically to revisit and improve on the older rule.

How much they differ

The gap depends heavily on age, because the two formulas have different slopes:

They agree almost exactly around age 40 and diverge in both directions from there. The traditional formula overestimates for younger people and underestimates for older people — and the older you are, the larger the underestimate.

That last point matters most. A 70-year-old using 220 − age is working from a maximum 9 bpm lower than the better estimate, which pushes every training zone down and can make prescribed efforts easier than intended.

Where 220 − age came from

The traditional rule was never derived as a careful regression. It emerged as a convenient approximation and became ubiquitous through repetition rather than validation. Its persistence is a good example of a number surviving because it is memorable rather than because it is accurate.

Tanaka's formula, by contrast, came from a systematic review and meta-analysis of published data plus a laboratory validation study. It is not perfect — no age-based formula can be — but it has a genuine evidential basis.

This is a smaller deal than it sounds

Having argued the case, some perspective is in order. Individual maximum heart rate varies by roughly ±10 bpm around any age-based prediction — which is larger than the gap between the two formulas for most people under 60.

So switching formulas is a genuine improvement, and it is a smaller improvement than actually knowing your own maximum would be. How accurate are heart rate zones covers what to do about that.

The practical upshot: use the better formula, and hold the resulting zones loosely regardless.

The bottom line

220 − age overestimates maximum heart rate for younger people and underestimates it for older people, with the error growing at both extremes. We use Tanaka's 208 − 0.7 × age because it was actually derived and validated for the purpose. See your zones on the Heart Rate Zones Calculator, and read how heart rate zones work for what to do with them.