How to Test your Lactate Threshold

In last week’s conversation I discussed why Lactate threshold is a better guide than maximum heart rate for heart rate run training.  

In a nutshell it’s becuase it gives you a more personalized and accurate measure of your aerobic capacity.

As promised, this week I’m going to lay out a simple way to test your lactate threshold on your own, meaning you need no fancy equipment (beyond your watch and ideally a heart rate chest strap for better accuracy) or a coach to deep dive into a load of data and do a lot of analysis.

The method I am going to explain here is not the only one, but it is the most accurate I have found for an athlete to do by themselves.

The Incremental Step Test

1) Complete an easy 10 minute warm up.

2) Run progressively faster 1/2 mile intervals, starting easy and increasing the pace each mile and take note of your average heart rate during each mile

Aim for a pace increase of 30 seconds per interval.

Take a short break between intervals to allow your heart rate to come down.

When you start to struggle to complete an interval or your heart rate stops increasing with increased effort, you are nearing lactate threshold.

The interval before you start struggling is around your lactate threshold pace and heart rate.

For example, if you struggled to complete the 7:30 pace interval but the 8:00 pace felt sustainable, your threshold is around an 8:00 mile pace. If your average heart rate during that 8:00 mile interval was 158, then your lactate threshold is 158.

You then confirm this by running a 30 minute time trial at your lactate threshold heart rate.

If you can sustain it for 30 minutes, it’s likely a valid measure of your lactate threshold.

Only do this test after a full period of recovery. If you try to go off to soon you will skew the data.

I advise doing this as a two day process, following a full rest day with the Incremental Test on day 1 and the Time Trail on day 2.

Retest every few months as your fitness improves. Using lactate threshold for training helps target the right intensities to build your endurance and speed.

About Liza Smith

Liza: The Endurance Expert – Unlock Your Peak Athletic Potential!

Dedicated to endurance, particularly in extreme events like Ironman, OCR and Ultras, Liza stands out not just as a coach but as an emblem of determination and tenacity.

With a reputation for moulding winners and transforming raw potential into prowess, Liza is the top pick for those aspiring to reign supreme in their sport.

Liza’s coaching philosophy centres on the power of the mind. Her five pillars – Control the Controllable, Find the Positive, Focus on You, 100% Effort, and Extreme Ownership – guide athletes to both mental and physical excellence.

Whether you're just starting out or vying for the gold, Liza ensures your hard work delivers results. Train with Liza and unleash the ultimate athlete within you.