Anaerobic Threshold Calculator

Your details

Your current age. Used to estimate maximum heart rate when no measured value is entered.
years
Tanaka (2001) is the most validated formula for adults. Fox (1971) is the traditional default. Nes (2013) is a recent alternative.
If you have a measured maximum heart rate from a lab test or recent all-out effort, enter it here. Leave at 0 to use the formula estimate.
bpm
Measure first thing in the morning before getting out of bed. Used for Karvonen heart rate reserve zones. Typical range 40-80 bpm.
bpm
Average heart rate over the last 20 minutes of a 30-minute all-out time trial. This is the most accurate field estimate of your lactate threshold HR. Leave at 0 to use the formula estimate.
bpm
Conventional range is 80-95% of max HR. Recreational athletes are typically around 80-85%; trained athletes often reach 88-92%.
%
Anaerobic thresholdRecreational range (80-85%)
156bpm

Your lactate threshold heart rate - the boundary between aerobic and anaerobic effort

Estimated max HR184bpm
AT zone lower bound154bpm
AT zone upper bound158bpm
Zone 1 upper limit125bpm
Zone 2 lower limit127bpm
Zone 2 upper limit152bpm
Zone 3 lower limit154bpm
Zone 3 upper limit172bpm
Zone 4 lower limit174bpm
Zone 4 upper limit182bpm
Zone 5 lower limit184bpm
HR reserve124bpm
156 bpm
Zone 1 - Recovery<120Zone 2 - Aerobic120-148Zone 3 - Tempo148-168Zone 4 - Threshold168-185Zone 5 - VO2 max185+

Anaerobic threshold: 156 bpm (85% of max HR).

  • Your anaerobic threshold is 156 bpm (85% of max HR), based on the formula estimate.
  • Your heart rate reserve is 124 bpm. A Karvonen 85% effort target is about 165 bpm, a useful cross-check.
  • Threshold work (Zones 3-4) falls between 154 and 182 bpm. Keeping most easy runs well below 152 bpm builds aerobic base without accumulating excess fatigue.
  • Lab lactate testing or a 30-minute time trial gives the most precise LTHR. Formula estimates can be off by 10-15 bpm for some individuals.

Next stepFor accuracy, run a 30-minute time trial at maximum sustainable effort and record average HR over the last 20 minutes. Enter that value in the Measured LTHR field to get precise training zones.

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