Lactate Threshold Heart Rate (LTHR)

Trench Sports - Lactate Threshold Heart Rate

This method of defining your heart rate zones is a bit more advanced than RPE or the Talk Test, but much more accurate over the long haul. For this method, we are going to find your Lactate Threshold Heart Rate (LTHR).

Lactic Acid is produced by the body and floods the muscles during exercise where it is naturally cleared by your body. When the amount of lactic acid entering the muscles exceeds the body's natural ability to clear it, the muscles begin to burn, hence the term, “Feel the burn”. This causes fatigue and you will need to rest to allow the lactic acid to be cleared, also known as recovering.

The goal of any endurance athlete is to hold a pace just below “the burn”, working your body as intensely as possible without having to stop because you are holding a pace where you are able to clear the lactic acid before “the burn”. Here is where we will find that pace and mark it with your heart rate. This is known as your Lactate Threshold Heart Rate (LTHR).

We will cover three different ways that you can find your LTHR depending on your endurance level.  These methods are best done either on a treadmill, where you can set your pace to be consistent, or on a flat road or track.  Hills offer a variation that can skew the results. We suggest that you retake these tests every few weeks as your endurance improves to make sure you are still working off of an accurate number.

These methods are...

  • 3x5 Max Effort
  • 20 Minute Max Effort
  • 60 Minute Max Effort

Learn how to perform them in our article, Find Your Lactate Threshold with these 3 Max Effort Tests.