Karvonen training zones from your age and resting heart rate.
Free to use, no sign-up required. Heart Rate Zones is one of 198 tools built into Xenition, alongside a chat that can use them for you.
Works out your five heart-rate training zones from your age and resting heart rate. Use it to set targets for recovery runs, tempo work or intervals on a watch or bike computer.
Maximum heart rate is estimated as 220 minus age. The Karvonen method then takes heart-rate reserve, which is maximum minus resting, and sets each zone boundary at resting + reserve × intensity, for 50–60%, 60–70%, 70–80%, 80–90% and 90–100%, rounded to whole beats. These are population estimates, not medical advice.
Age 40 and resting 60 bpm give a maximum of 180 and a reserve of 120. The zones are 120–132 (Warm-up), 132–144 (Fat burn), 144–156 (Aerobic), 156–168 (Anaerobic) and 168–180 bpm (Max).
Two people with the same maximum but different fitness have different working ranges. Karvonen scales each zone from your resting rate, so a fitter person with a lower resting rate gets lower bottom limits.
It is an average; individual maximums often differ by 10 beats or more. A supervised test or a hard effort on a heart-rate strap gives a better personal figure.
You do not have to open Heart Rate Zones to use it. Ask Xenition in plain language and it runs the right tool, then carries the answer into whatever you are working on — a document, a spreadsheet, a deck.