Neverpedia
Heart rate
LTHR (Lactate Threshold Heart Rate)
The heart rate at which lactate begins to accumulate faster than your body can clear it.
Lactate Threshold Heart Rate (LTHR) is the heart rate that corresponds to the workload at which blood lactate starts accumulating faster than your body can clear it. It is the heart-rate equivalent of FTP.
How it is measured
- Field test: A 30-minute all-out effort. Average HR for the final 20 minutes is a good LTHR estimate (Joe Friel protocol).
- Lab test: Blood lactate sampling at increasing workloads — the gold standard but rarely available.
- Estimation from races: Average HR during a 30–60 minute hard race effort often lands very close to LTHR.
Why it matters
LTHR anchors heart-rate-based training zones. It is more useful than max heart rate for setting zones because it reflects current fitness, not genetic ceiling.
Common misconceptions
- LTHR is not the same for every athlete at the same fitness level. It is individual.
- LTHR is not the heart rate you "should" hit during all training. Most of your training should happen well below it.
- LTHR does not equal max heart rate minus 10 bpm. Stop using rules of thumb — test it.
Related concepts
Max HR, FTP, Threshold, Zone 2.