Heart rate
LTHR Zone Calculator
Use this when you have a threshold heart-rate result and want zones that do not depend on age-estimated max heart rate.
- Uses LTHR as the reference.
- Shows five continuous training ranges.
- Labels the confidence of the threshold source.
LTHR zones anchor training intensity to a threshold result instead of an age-estimated maximum.
- Prefer a laboratory or well-executed field-test result.
- Use a stable average, not a brief heart-rate spike.
- Repeat testing under similar conditions after a meaningful fitness change.
The ranges are practical training guides. Threshold source and testing conditions determine how much confidence to place in them.
- Validate easy zones with breathing and talk test.
- Keep threshold work controlled rather than chasing the top of the range.
- Recheck the input when zones stop matching effort.
Use the easy range on one steady run and compare it with breathing, pace, and recovery.
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.
What are my running zones from LTHR?
Input confidence
LTHR zones are training guides, not blood-lactate measurements or medical advice. Recheck the input when fitness, heat, fatigue, or testing conditions change.