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What Z1–Z5 actually mean, how to find your max heart rate, and how to train each zone.
The Tanaka formula — 208 minus 0.7 times your age — predicts maximum heart rate more accurately across ages than the older 220-minus-age rule. Your five zones are then percentages of that maximum.
The Tanaka formula — 208 minus 0.7 times your age — predicts maximum heart rate more accurately across ages than the older 220-minus-age rule. Your five zones are then percentages of that maximum.
Z1–Z2 build aerobic base and recovery, Z3 is tempo, Z4 sits at lactate threshold, and Z5 develops VO₂ max. Most endurance gains come from spending the majority of training time in Z2.
Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990 · Tanaka H, et al. J Am Coll Cardiol. 2001 · Morton RW, et al. Br J Sports Med. 2018 · Last updated Feb 2026.
Drafted with AI assistance, then edited and fact-checked by the Clinarix editorial team against the cited primary research. Educational information only — not medical advice. See our standards.