Max heart rate formulas compared: 220 - age vs Tanaka, and what moves zone 2

The two formulas

220 - age is attributed to Fox, Naughton and Haskell (1971) and, in the words of the Tanaka paper, is the commonly used equation for prescribing exercise. 208 - 0.7 x age comes from Tanaka, Monahan and Seals (2001), who pooled group mean maximum heart rates from 351 studies (492 groups, 18,712 people) and then checked the result in a laboratory study of 514 healthy adults, where they got 209 - 0.7 x age. They found no difference between men and women, and no effect of habitual activity level. Their abstract states that the older equation underestimates maximum heart rate in older adults.

The heart rate zone calculator offers both, plus your own measured maximum.

The gap, age by age

Subtract one formula from the other and the age terms leave a simple line: 220 - age - 208 + 0.7 x age = 12 - 0.3 x age. It is zero at 40 (12 / 0.3), positive below and negative above, and it changes by 3 bpm per decade. I computed both maxima and the zone 2 range, 60 to 70% of max, for each decade:

Between 30 and 50 the formulas sit within 3 bpm of each other and the zone 2 ranges overlap almost completely. At 70 and 80 they part: an 80-year-old using 220 - age gets a zone 2 ceiling of 98 bpm, while Tanaka's formula puts the ceiling at 106. Following Tanaka's own conclusion, the older formula would set an older runner's easy zone lower than the population data support.

The bigger lever: Karvonen and a low resting pulse

Karvonen's method (1957) does not take a share of the maximum. It takes a share of the heart rate reserve, the gap between resting and maximum, and adds it back to the resting rate: target = rest + % x (max - rest). Because the resting rate is the starting point, the same "60 to 70%" lands much higher in beats per minute.

Worked example, age 50, Tanaka maximum 208 - 0.7 x 50 = 173 bpm, resting rate 45. Reserve = 173 - 45 = 128. Zone 2 = 45 + 0.6 x 128 to 45 + 0.7 x 128 = 121.8 to 134.6, rounded 122 to 135 bpm. As a share of maximum, that is 70.4% to 77.8%. The percent-of-max version for the same person is 0.6 x 173 to 0.7 x 173 = 104 to 121 bpm.

So for this runner, the choice of method shifts zone 2 by 18 bpm at the bottom and 14 at the top. The choice of age formula, by comparison, never shifts it by more than 8 bpm between 20 and 80. The lower the resting heart rate, the closer Karvonen stays to percent of max; the higher it is, the more Karvonen moves the zone up. A resting rate of 70 puts the Karvonen zone 2 at 76 to 82% of max, which overlaps what the percent-of-max scheme calls zone 3 and zone 4.

Four setups for one runner

Put both choices together and the spread gets wider. For a 65-year-old with a resting heart rate of 55, here are zone 2 (60 to 70%) and zone 4 (80 to 90%) under each combination of formula and method:

The lowest zone 2 floor is 93 bpm, the highest 120: 27 beats apart for the same person on the same day. Zone 4 tops out anywhere from 140 to 152. None of these is wrong by its own definition, which is the point: a heart rate number only means something next to the formula and the method that produced it. If you change watches or plans, check both before comparing your old and new zones.

Why the two zone 2s are both "right"

They are different definitions using the same words. A percent of maximum and a percent of reserve are different scales; neither is wrong, but a zone 2 number copied from a plan that used one scale does not transfer to the other. If you read a plan, check which one it uses before you set your watch. The five 10% bands used on this site are a common model, not a medical standard.

What a formula can and cannot tell you

Tanaka's equation was fitted to group averages. It predicts a population mean for your age, and individuals scatter around that mean. In the meta-analysis, maximum heart rate tracked age very closely (r = -0.90), but that figure describes how the averages of 492 groups line up, not how close any one person sits to the line. The laboratory check, 209 - 0.7 x age, differs from the published equation by just 1 bpm at every age, which is why the 208 version is the one in use. That is why the calculator lets you type a measured maximum, which replaces both formulas. If you have a reliable maximum from a hard, all-out effort on a chest strap, it beats either line in the table.

A resting heart rate is easier to measure well: count your pulse for a full minute after waking, before getting up, on a few mornings, and use a typical value.

Heart rate and pace together

Heart rate drifts upward on long or hot runs at a steady pace, so a pace guide is a useful cross-check. The training pace calculator sets easy, threshold and interval paces from a race, and the VO2 max calculator gives an aerobic fitness estimate from a field test or a race. For how the race-based pace model treats intensity over long durations, see how long you can hold a pace.

Limits

Both age formulas describe healthy adults on average. Medication that affects heart rate, such as beta blockers, makes any formula meaningless, and heart conditions call for zones set by a doctor. This is not medical advice. If you have a heart condition, take heart-rate-lowering medication, or are new to hard exercise, ask your doctor for your training zones before using a formula, and do not attempt an all-out effort to find your maximum without clearance.

Sources: Tanaka H, Monahan KD, Seals DR (2001), Age-predicted maximal heart rate revisited, J Am Coll Cardiol 37(1):153-156; Fox SM, Naughton JP, Haskell WL (1971), Physical activity and the prevention of coronary heart disease, Ann Clin Res 3(6):404-432; Karvonen MJ, Kentala E, Mustala O (1957), The effects of training on heart rate; a longitudinal study, Ann Med Exp Biol Fenn 35(3):307-315; Maninthorn R et al. (2025), Fox vs Tanaka maximum heart rate and percentage vs Karvonen methods, Int J Exerc Sci (PMC12408077). Rules checked 7 October 2026. Found a problem? Tell us.

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