Heart Rate Zone Calculator (Karvonen Method)
- Calculator
- About 3 min
- Karvonen 1957 heart rate reserve, Tanaka 2001 max heart rate
- Runs in your browser, nothing is sent
- Medical review: Medical review pending
What this calculator works out
A training zone is a heart rate range that corresponds to a physiological effort. The Karvonen method anchors each zone to your own reserve, the gap between resting and maximal heart rate, so the numbers reflect you rather than an average person of your age.
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1
Your maximal heart rate
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2
How precise your zones are
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3
Five zone boundaries
How this compares with a typical online quiz
| Feature | Typical free quiz | Regenerated.com |
|---|---|---|
| Resting heart rate used | Rarely; flat percent of max | Yes, the Karvonen reserve method |
| Max heart rate formula named | Often 220 minus age, unsourced | Tanaka 2001, with its scatter stated |
| Measured max accepted | Sometimes | Yes, it overrides the age estimate |
| Zone meanings sourced | No | ACSM intensity classes and the polarized training literature |
| Medication caveat | No | Yes, beta blockers and other rate-lowering medicines |
| Answers sent to a server | Often | Never; scored in your browser, counts-only events |
What each zone trains
Zone 1 (50 to 60 percent of reserve) is recovery: walking, easy spinning, the warm-up and cool-down. Zone 2 (60 to 70 percent) is the easy aerobic range where you can hold a conversation in full sentences and breathe through your nose for stretches; it builds mitochondrial density, fat oxidation and the capillary network that everything harder depends on, and it is where most endurance athletes spend 70 to 80 percent of their training time. Zone 3 (70 to 80 percent) is the tempo range: comfortably hard, sentences broken into phrases. Zone 4 (80 to 90 percent) sits around the lactate threshold, sustainable for 20 to 60 minutes by trained people. Zone 5 (90 to 100 percent) is the VO2 max range, held in intervals of a few minutes with equal or longer recoveries.
The ACSM position stand on exercise prescription (Garber and colleagues, 2011) classifies intensity by percent of heart rate reserve: light below 40 percent, moderate 40 to 59 percent, vigorous 60 to 89 percent, near-maximal 90 percent and above. Public health guidance for adults, 150 minutes a week of moderate or 75 minutes of vigorous activity, maps onto zones 2 to 4 of this page. The five-zone split is a coaching convention layered on those classes, not a separate physiology.
A simple week for a healthy adult who is not racing: three to four sessions of 30 to 60 minutes in zone 2, one session with 15 to 25 minutes in zone 4 or four to six intervals of three to four minutes in zone 5, and the rest in zone 1. Heart rate lags effort by a minute or two, so judge intervals by the end of each repetition rather than the start, and let breathing and the talk test overrule the watch when they disagree.
How to measure resting and maximal heart rate
Resting heart rate is best taken lying down on waking, before coffee, for three or four mornings, and averaged. A watch that records overnight heart rate gives a similar number; use its lowest sleeping value if that is what it reports, and note which one you used so later comparisons match. Illness, poor sleep, alcohol, heat and a hard session the day before all raise it by 5 to 10 beats, which is also why a rising resting rate over several days is a useful signal to back off.
A true maximal heart rate comes from a maximal exercise test or from a very hard effort such as the last minute of an all-out 5 km or a series of hill repeats to exhaustion, after a thorough warm-up, in someone healthy enough to do that safely. The age formula is a population average: the Tanaka equation's standard deviation is about 10 beats per minute, so one adult in three has a true maximum more than 10 beats from the estimate, and the Karvonen zones inherit that error. If your hardest efforts routinely take you above your estimated maximum, enter the number you have actually seen.
Beta blockers, some calcium channel blockers, ivabradine and certain antiarrhythmics lower exercise heart rate, and heart rate zones built on an age formula are wrong for people taking them. Use perceived exertion or the talk test instead, or ask the prescribing clinician for a measured test.
Methodology and sources
The calculator implements the heart rate reserve method described by Karvonen, Kentala and Mustala in 1957. Heart rate reserve is maximal heart rate minus resting heart rate, and each zone boundary is the resting rate plus the reserve multiplied by an intensity fraction, from 50 to 100 percent in steps of ten. When no measured maximum is entered, maximal heart rate comes from the Tanaka equation, 208 minus 0.7 times age, derived by Tanaka, Monahan and Seals in 2001 from a meta-analysis of 351 studies and a laboratory sample of 514 healthy adults. The Tanaka equation has a standard deviation of roughly 10 beats per minute around the prediction, and the Karvonen method was described in young men; both are planning tools rather than measurements, and the reserve method's advantage over a flat percentage of maximum is that it accounts for individual resting rate.
How this is calculated: at age 40 with a resting rate of 60, the Tanaka maximum is 208 minus 28 = 180 beats per minute and the reserve is 180 minus 60 = 120. The 60 percent boundary is 60 + 0.6 x 120 = 132, the 70 percent boundary is 60 + 0.7 x 120 = 144, and the 80 percent boundary is 60 + 0.8 x 120 = 156. Zone 2 for this person therefore runs from 132 to 144 beats per minute. A measured maximum replaces the 180 and every boundary shifts with it.
The zone descriptions follow the intensity classes in the ACSM position stand (Garber and colleagues, 2011), which define moderate intensity as 40 to 59 percent of heart rate reserve and vigorous as 60 to 89 percent, and the distribution guidance draws on the polarized training literature summarized by Seiler (2010). The result bands on this page read the maximal heart rate behind the zones (the 100 percent boundary, which equals the measured or estimated maximum) and are educational groupings written to say how precise your zones are and whether the resting rate deserves attention; they are not clinical cut-offs. A resting heart rate persistently above 80 to 90 beats per minute in an adult at rest is worth raising with a clinician.
Medical review: Medical review pending. Last updated .
References
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate: a longitudinal study. Ann Med Exp Biol Fenn. 1957;35(3):307-315.
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156.
- Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011;43(7):1334-1359.
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform. 2010;5(3):276-291.