Heart rate
Heart Rate Reserve Calculator
Use this when you know resting heart rate and want a more personalized range than simple percent-of-max zones.
- Uses heart rate reserve: max heart rate minus resting heart rate.
- Adds the reserve percentage back to resting heart rate.
- Useful when two runners have the same max heart rate but very different resting heart rates.
Heart-rate reserve includes resting heart rate, so it can produce more individual training ranges than percent of max alone.
- Use a recent resting heart rate measured after waking.
- Use a reliable max heart rate, not only a default watch estimate.
- Recheck resting heart rate after illness, poor sleep, or heavy training blocks.
Karvonen zones often sit higher than simple percent-max zones for fit runners with low resting heart rate.
- Compare reserve zones with breathing and perceived effort.
- Do not force Zone 2 if it no longer feels easy.
- Track resting heart rate trends as a recovery signal.
Use reserve zones for a few easy runs and adjust if the numbers do not match effort.
Heart-rate calculators Heart-Rate Zone Calculator Estimate easy, steady, and hard running zones. Heart-Rate Drift Calculator Estimate aerobic decoupling from a steady run. Max Heart Rate Calculator Compare age estimates with observed hard-effort readings. Heart Rate Reserve Calculator Use resting and max heart rate for personalized ranges. LTHR Zone Calculator Calculate zones from lactate threshold heart rate.