So here’s why it is good to be familiar with both RPE and LTHR. Whenever you are doing any type of interval training you will be bouncing from Zone to Zone. If you are going strictly off your LTHR it can get tricky.
Let’s say you are performing interval runs. You are at Zone 2 for one minute, then jump to Zone 5 for 30 seconds, and then back to Zone 2.
Your heart rate will most likely not reach Zone 5 until after the 30 seconds is up. Even your return to Zone 2 will take a little bit before your heart rate matches your Zone 2 range. This is known as Heart Rate Lag Time.
This is when it becomes good practice to use your RPE and feel your way in between your Zones. Just because your heart rate isn’t accurately representing which Zone you are in, you are still transitioning between zones correctly by feeling your way with RPE.
Knowing your pace is extremely useful because that is a number range that you can drop right into without worrying about how you feel or waiting to see if your heart rate drops to the correct level. We’ll save that for another level of training.
However, when you retake these tests to track your LTHR, track your pace as well. Your Zone 3 pace at the beginning of your training will most likely be a lot different than your Zone 3 pace after a few months of training. You will be getting faster without increasing your HR. Which is the whole idea, more speed with less effort.
It might seem a little confusing but just keep this in the back of your mind while transitioning between zones. It’ll make more sense once you get out there and start doing it. It will fall into place with a little experience under your belt… trust us.