Heart Rate Zone Calculator

Not for individuals. The formula has no research derivation — it was an informal fit published in 1971 — and studies measuring real maxima find a standard deviation of 10 to 12 bpm around any age prediction. For a 40-year-old that means a true maximum plausibly anywhere from 160 to 200. It also reads low for older adults: Tanaka’s 208 − 0.7 × age gives 180 at 40 against 220 − age’s 180, but 173 at 50 against 170, and the gap widens with age.

Percent of maximum takes a share of the maximum heart rate. Heart rate reserve — the Karvonen method — takes a share of the gap between resting and maximum, then adds the resting rate back. For someone with a 190 maximum and a 50 resting rate, 70% of maximum is 133 bpm but 70% of reserve is 148 — 15 bpm apart, which is more than a zone wide. Karvonen accounts for fitness, since a trained person’s low resting rate widens the reserve.

Most of it in zone 2 — easy aerobic work where you can hold a conversation — with a small share hard, in zones 4 and 5. The common mistake is spending the week in zone 3: hard enough to accumulate fatigue, not hard enough to drive adaptation. Zone 1 is warm-up, cool-down and recovery, and is not wasted time.

A graded maximal test under supervision is the reliable way. A practical alternative for a trained, healthy person is the highest rate seen in a hard race or a session of long hill repeats to exhaustion — treadmill maxima tend to run a few beats above cycling ones for the same person. Do not attempt a maximal effort to find the number if you have a heart condition, symptoms on exertion, or no recent training history.

Yes, substantially. Beta blockers lower both resting and maximum heart rate, sometimes by 20 to 30 bpm, so an age-predicted maximum is meaningless on them and the zones derived from it are wrong. Some other drugs and conditions do the same. If you take anything affecting heart rate, ask your clinician for a target based on your actual response, or train by perceived effort.

A max heart rate calculator usually starts from 220 minus age, which gives 185 for a 35-year-old, though the true figure varies by 10 beats or more either side. A target heart rate calculator then takes a percentage of that maximum, or of the reserve above your resting rate, for each zone: 70% to 80% of maximum for steady endurance work, 80% to 90% for threshold. If you have a measured maximum from a hard effort, enter it instead of the estimate and the zones tighten considerably.

The Karvonen formula sets zones from heart rate reserve, the gap between resting and maximum, rather than from the maximum alone: target = resting + (maximum − resting) × intensity. A Karvonen calculator therefore gives two people with the same maximum different zones if their resting rates differ, which is more realistic than the plain percentage method. The fat burning heart rate zone that a fat burning heart rate calculator returns is usually 60% to 70% of maximum, where fat supplies the largest share of the fuel; it is not where the most fat is burned in total, since harder training zones burn more calories overall. A training zones calculator like this one shows all five so that distinction is visible.