I talk a lot about physiological profiling, and how getting tested in an exercise physiology laboratory can be really helpful for refining your training. However, I also know that many athletes do not have access to exercise physiology labs for this testing.

Accordingly, I’ve put together a couple of calculators on the Endure IQ website that you can use to get decent estimates of things like intensity thresholds using easy-to-access field test data.

In this section we are going to talk about the metabolic calculator. I’ll walk you through how to perform the field tests to get the necessary data. But we also include calculators for critical swim speed, functional thresholds power, and critical running speed.

#1: The metabolic calculator

Our first calculator, which you can find here, uses field test estimates of your VLa_max and VO₂max to predict your two lactate thresholds – which we use to determine training zones – and your Fat_max, or the intensity at which...

Sooner or later, as an endurance athlete, you will come across a discussion of ‘lactate’, whether you are also an exercise physiologist or not. Blood lactate concentrations are routinely measured in endurance athletes, and so-called ‘lactate thresholds’ are used to inform training decisions. Some athletes and coaches even spot-test blood lactate concentrations during exercise to regulate intensity during training. And this is becoming more popular than ever – word on the street is in Kona this year, just about every athlete stopped to take lactate. Of course, this has been massively popularized by the Norwegian program's success, and rightly so! They are doing some amazing things!

However, I believe many people misunderstand what lactate is and isn’t and what blood lactate responses to exercise can and can’t tell you. So, in this blog, I will briefly summarise some of the fundamental physiology of lactate metabolism. Brace yourself for some...