Target Heart Rate Zones Calculator

The Karvonen method uses your Heart Rate Reserve (Max HR − Resting HR) instead of raw max HR. Because it anchors the lower end to your resting HR, two people with the same max HR but different resting HRs get different zone ranges — which more accurately reflects their individual cardiovascular fitness.

Tanaka (208 − 0.7 × Age) is generally recommended for adults. A 2001 meta-analysis by Tanaka et al. found it has lower prediction error than 220−Age, particularly for people over 40. If you have a measured max HR from a recent hard effort, use that instead — it will be the most accurate.

Measure first thing in the morning before getting out of bed, after at least 5 minutes of lying still. Count beats for a full 60 seconds, or use a reliable wearable. Illness, alcohol, caffeine, and poor sleep can elevate resting HR by 5–15 bpm, so take readings on multiple calm mornings and average them.

Zone 2 (60–70% of HRR) is sometimes called the 'aerobic base' zone. At this intensity, fat oxidation is highest and mitochondrial density improves with training. Most elite endurance athletes spend 70–80% of total training volume in Zone 2 to build an aerobic engine without accumulating excessive fatigue.

Zone 4 sits near your lactate threshold — the intensity at which lactate begins to accumulate faster than it can be cleared. Training here raises your threshold pace, meaning you can sustain faster speeds aerobically. Classic formats include 20–40 min tempo runs and 2×20 min cycling intervals.

Yes. Swim heart rates are typically 10–15 bpm lower than running HR at equivalent perceived effort, due to the horizontal body position, cooler water temperature, and facial immersion reflex. Apply a correction of approximately −10 to −13 bpm to the zone boundaries if using these zones for pool swimming.

Generally yes for cycling (the zones are closely comparable to running). Rowing HR tends to run slightly lower than running due to the upper-body involvement distributing cardiac output differently. Small individual variation exists, so perceived effort and power output are useful cross-checks.

Beta-blockers suppress max HR and resting HR, making standard age-predicted formulas and even measured max HR tests unreliable for zone calculation. In this case, use perceived exertion (RPE scale) or lactate testing under medical supervision instead of HR zones.

Resting HR can improve by 5–10 bpm after 3–6 months of consistent aerobic training, which shifts all zones. Recalculate whenever your resting HR changes noticeably, after a significant fitness break, or at the start of a new training block — typically every 3–6 months.

The CDC and American Heart Association define a normal resting HR for adults as 60–100 bpm. Well-trained endurance athletes commonly have resting HRs of 40–55 bpm. Values below 60 in non-athletes warrant medical review, as does a resting HR consistently above 100 bpm.