Orpheus

Training Heart Rate Zones

Five zones, from your maximum and resting rate.

Inputs
years
bpm

Measured on waking, before getting up. Leave at 60 if you do not know it.

Maximum heart rate
187bpm
Zone 1 · Recovery (50–60%)
124–136bpm
Zone 2 · Endurance (60–70%)
136–149bpm
Zone 3 · Tempo (70–80%)
149–162bpm
Zone 4 · Threshold (80–90%)
162–174bpm
Zone 5 · Maximal (90–100%)
174–187bpm
Heart rate reserve
127bpm
Karvonen: target = ((max − resting) × intensity) + resting

Zones use the Karvonen method, which works from your heart rate reserve rather than a flat share of maximum — that is why the resting figure changes every zone. Maximum is estimated with Tanaka (208 − 0.7 × age), not 220 − age.

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Zones are percentages of heart rate reserve — maximum minus resting — added back to resting. With a maximum of 187 and resting of 60, zone 2 at 60 to 70% is 136 to 149 beats per minute.

How to use Heart Rate Zone Calculator

  1. Enter your age. Used to estimate maximum heart rate with the Tanaka formula.
  2. Enter your resting rate. Measured on waking. It shifts every zone, so a real figure is worth having.
  3. Read the five zones. Recovery through maximal, in beats per minute.

About calculating heart rate training zones

Heart rate zones exist to make training intensity measurable rather than guessed. The complication is that both inputs to a zone calculation are estimates, and the commonly used ones are poor. The familiar 220 minus age was never the product of a controlled study; it emerged as a rough line fitted through earlier data and carries a standard deviation of more than ten beats, drifting furthest exactly where it is most used — it tends to under-read for older and fitter people, prescribing training that is too easy. The Tanaka equation, 208 minus 0.7 times age, fits the published evidence substantially better and is what is used here. The second choice is how a percentage becomes a target. Taking a flat share of maximum ignores resting heart rate entirely, which means a well-trained person resting at 45 and an untrained person resting at 75 get identical prescriptions despite having very different amounts of usable range. The Karvonen method works from heart rate reserve — the gap between resting and maximum — and adds resting back, which distributes the zones across the range each person actually has. Both remain population estimates. A genuine field test produces a personal maximum, and a training plan built on one is worth more than any formula, however well fitted.

Frequently asked questions

Why not use 220 minus age?
Because it was never derived from a controlled study — it came from a rough fit across earlier data and carries a standard deviation of over ten beats. It systematically under-reads for older people. The Tanaka equation, 208 minus 0.7 times age, fits the published data considerably better.
What is the Karvonen method?
It takes percentages of your heart rate reserve — maximum minus resting — and adds the resting rate back. This matters because a fit person with a resting rate of 45 and an unfit person at 75 should not train at the same absolute numbers despite sharing an age.
What is zone 2 training and why is it emphasised?
Zone 2 is the conversational pace at roughly 60 to 70% of reserve. It is emphasised because it builds aerobic capacity with low recovery cost, so a large volume can be sustained week after week — which is what actually produces endurance adaptation, rather than intensity alone.
How do I measure my resting heart rate properly?
On waking, before getting out of bed, averaged over several mornings. Anything measured after coffee, movement or stress reads high. A wearable that samples through the night gives a more reliable figure than a single manual count.
Are these numbers exact?
No. Any age-based formula is a population estimate, and individual maximums vary by ten beats or more in either direction. A properly conducted field test gives a personal figure; until then treat these as a starting range rather than a prescription.

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