HesapHanem

Lactate Threshold Heart Rate Calculator

Get your LTHR and the five heart-rate zones built on it.

How it is calculated

You choose a method and enter one heart rate in beats per minute. With the 30-minute time trial or the 60-minute race method, that heart rate (the average of the final 20 minutes of the trial, or of the hard hour) is taken as LTHR directly. With the max-HR method the number you enter is your maximum and LTHR = 0.90 × max. Zones are fixed percentages of LTHR: zone 1 below 85 %, zone 2 85–89 %, zone 3 90–94 %, zone 4 95–99 %, zone 5 at 100 % and above. Each edge is rounded to a whole bpm, which can leave a 1 bpm gap between zones. The optional maximum heart rate adds LTHR as a percentage of it, otherwise a dash is shown. A test heart rate outside 60–250, or a maximum heart rate below the number you typed in the main box, gives no result.

Worked example

A 30-minute time trial with an average heart rate of 165 bpm over the final 20 minutes, and a maximum of 185 bpm. LTHR = 165 bpm. Zone 1 is below 0.85 × 165 = 140 bpm. Zone 2 is 140–147 bpm (85 % to 89 % of 165). Zone 3 is 149–155 bpm, zone 4 is 157–163 bpm and zone 5 is 165+ bpm. LTHR as a share of maximum is 165 ÷ 185 = 89%.

Try this example →

Common mistakes

  • Entering the average heart rate of the whole 30 minutes instead of only the final 20. The first 10 minutes run lower and pull the value down.
  • Choosing the max-HR method and typing an LTHR in the box. In that mode the number is read as your maximum and multiplied by 0.90.
  • Entering a maximum heart rate lower than the heart rate in the main box. A maximum cannot be below the heart rate you reached in the test, so the tool shows no result; check which number belongs in which box.
  • Expecting the 30-minute and 60-minute options to differ. Both use the entered average as LTHR; only the max-HR option changes the arithmetic.
  • Treating zone edges as exact. Rounding leaves gaps such as 147 to 149 bpm, and a single field test can be off on a bad day.

Sources

About this calculator

Lactate threshold heart rate (LTHR) is the heart rate at which lactate starts accumulating in the blood faster than the body can clear it — roughly the highest intensity you could sustain for about an hour. Coach Joe Friel popularized estimating it from a field test rather than a lab: a 30-minute all-out time trial (averaging the heart rate over the final 20 minutes) or a 60-minute race effort, and from that single number Friel derives five training zones, from easy recovery through threshold to anaerobic-capacity work.

Runners and cyclists use LTHR-based zones as the backbone of structured training plans because, unlike percent-of-max-heart-rate zones, they are anchored to a physiological marker that shifts as fitness improves, making them more precise for prescribing easy, tempo, threshold and interval efforts. It is a staple of TrainingPeaks-style periodization and of cycling and running plans built around Friel's methodology.

Was this helpful?

You can pick up to 3 reactions.

Comments

  • Be the first to comment.

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators