This at-home Anaerobic Threshold test will help you determine your Anaerobic Threshold (AnT) heart rate, which will be useful when it comes to controlling and monitoring your training. You should perform it at least three days after any hard efforts. It can be done either on a steep treadmill (15 percent), a steep uphill, or, if you are a well-trained runner, you can do it on the flats. The test portion (excluding warm-up) will take at least 30 minutes and up to 60 minutes.

You will need a recording heart rate monitor. This test requires maximal output so you need to be physically and mentally ready for a hard effort. If you are new to training use a 30min test length. If you are very well trained with many years of aerobic training under your belt, you can use a 60min test length. If you think you are somewhere between then use a 45min test length.

You will want to be well fueled prior to testing. Make sure you ate your most recent meal at least 120 minutes pre-testing and ideally top up with a light carbohydrate-focused snack of about 100 calories within 30-45 minutes of beginning the test.

Anaerobic Threshold Test Step-by-Step Guide

  1. Make sure heart rate monitor is working and ready to record the whole workout.
  2. Do a 15-minute warm-up at or below your Aerobic Threshold (AeT) or until you break a sweat. Ease into this warm-up so that your aerobic system is fully online.
  3. As soon as you are done with the warm-up, continue immediately into the AnT test. Once you start, go as hard as you can sustain for the full 30 minutes.
  4. Pace yourself so that you don’t blow up 5 minutes into the test.
  5. Note your average heart rate for the 30-minute test. This will be your AnT heart rate. Note that less fit athletes will need to use 30-minute efforts while very fit ones should go for 60 minutes. This is because the less fit will succumb to local muscular fatigue, causing them to prematurely slow (which will result in a lower heart rate). These less fit athletes will need to do shorter repetition lengths in their interval sessions so that this local effect does not negatively impact the effectiveness of their interval training.

The 10 Percent Test

Once you have your AnT heart rate, subtract your previously determined AeT heart rate from it. Example: AnT heart rate from this test = 165. AeT heart rate from that test = 152. 165–152 = 13.

If the difference is 10 percent or less of the AnT heart rate, then you will need to reduce the amount of Z2 training and substitute more Z1 for your aerobic base training or you will run the risk of overtraining by running too fast (Z2) too much of the time.

Ten percent of 165 = 16.5. So in the above example, 13 is less than 10 percent.

If the spread between your AeT and AnT is more than 10 percent, then do all of your aerobic base training in Z2. Redo the AeT test that you did on day 1 each month if this is the case. As your aerobic base improves and your AeT heart rate and pace move upward, you will need to adjust the volume of Z2 down.


We find that it is useful to test both AeT and AnT near the beginning of starting a season’s training, and it may be useful to retest periodically. If you are using TrainingPeaks to record and analyze your training, which we recommend, these two numbers are important markers that allow the algorithms to accurately estimate your Training Stress Score (TSS), Chronic Training Load (CTL), and other useful measures available on that platform.

For a full rundown of Uphill Athlete’s recommended methods for determining AeT and AnT, read “Aerobic Self-Assessment for Mountain Athletes.”

You May Also Be Interested In:

Comments are closed.