Running, Triathlon
November 17, 2020

A Simple Guide To Lactate Testing

Analyser measuring blood lactate during a lactate test

I did my first lactate test when I was about 17-years old. From that point on, and especially during the later stages of my pro career, my coaches regularly scheduled lactate tests in each of the disciplines (swim, bike and run), to track my fitness and to determine my training zones.

On occasion, I did the tests out in the field; on the track, roads and in the pool. More often, though, I did lactate testing in a lab, just like the one we operate at Coached.

Besides being a nice break from my traditional training schedule, lactate testing provided valuable insight into what was happening to my body, and how my fitness was progressing as I continued to build and refine my training load over time.

Whether you’re a triathlete, runner, cyclist, swimmer or rower, as an endurance athlete, you need accurate physiological data to guide and monitor your training. Lactate testing is one of the most common and effectively used performance tests used by many athletes and coaches.

In this post, I’ll explain what lactate is and why testing it is useful for establishing training zones and tracking progress.

What Is Lactate?

You produce lactate when your body breaks down carbohydrates (in the form of glycogen or glucose) anaerobically (without oxygen) to produce energy. This process is called ‘glycolysis’. The end-product of this reaction is a substance called ‘pyruvate’. Some of this pyruvate is then transported into the mitochondria of the cell, and processed by the aerobic energy system to produce more energy, along with some harmless water and carbon dioxide.

What’s left of the pyruvate is converted into lactate and some hydrogen ions. Lactate then typically enters the bloodstream, where it’s transported to other cells in your body and oxidised to produce energy.
Many people think lactate is the reason for fatigue when you’re training or racing hard, but that’s not the case. It’s the hydrogen ions you produce alongside lactate that cause the blood and muscles to become acidic, leading to fatigue. Lactate can be considered a temporary fuel source.

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What Is Lactate Threshold And Why Is It Important?

The lactate threshold, also known as the anaerobic threshold, maximal lactate steady state (MLSS), onset of blood lactate accumulation (OBLA) etc., is the highest output (heart rate/pace/power) that you can sustain without a continual increase in muscle and blood lactate.

Once you cross your lactate threshold, you rely more heavily on your glycolytic system for energy. At this intensity, it won’t be long before you have to slow down or stop due to the accumulation of blood lactate hindering your muscles’ ability to contract.
The purpose of training is to move your lactate threshold so that it occurs at a higher output. The more work you can do before you reach lactate threshold, the better.

What Is Lactate Testing?

Lactate testing is a test done to determine your lactate threshold and establish training zones based on actual metabolic conditions within your body. Zones established this way, therefore, have better physiological validity than zones based on FTP, FTPa or heart rate (e.g. max heart rate) anchor points.

Lactate testing can be done in the field, or in a lab, using a small analyser to measure the lactate concentration in your blood. In the Coached Lab, we conduct lactate testing on either a bike or treadmill, depending on the sport the athlete is preparing for.

Before the test, we measure heart rate and take a pre-test blood sample to establish a baseline lactate reading. The athlete then completes a step test, with each stage increasing by 1km/h. We take RPE, heart rate, speed/power, and lactate readings at the end of each stage. The exact protocol is based on an athletes ability and the test ends when the athlete has reached their lactate threshold.

The Results

There are three types of results we’ll typically see in our lab. The first two we see regularly, the last one is less common.

1. A Linear Curve
A linear curve represents an unfit athlete or someone who has been training regularly at high intensity.

A linear lactate curve represents an athlete who is very unfit

2. A Normal Curve
A normal curve represents an athlete who has some background in training and has a reasonable aerobic base.

A normal lactate curve represents an athlete who has some background in training and has a reasonable aerobic base.

3. A Steep Curve
A steep curve represents an athlete who is very fit and experienced and reaching close to their maximum potential.

A steep lactate curve represents an athlete who is very fit and experienced and reaching close to their maximum potential.

Moving The Curve

The purpose of training is to move your lactate threshold so that it occurs at a higher output. This change is illustrated by a shift to the right of the lactate curve, as seen in the graph below.

An improvement in fitness is illustrated by a shift to the right of the lactate curve, as seen in the graph

To do this, you need to use the zones established during testing, and structure your training with a mix of sessions designed to reduce your lactate production while improving your clearance and threshold.

Long(ish), easy(ish) zone one and two sessions are great for increasing mitochondrial development, and therefore lowering lactate production.

Sessions where you train alternating just above and just below your lactate threshold work well to improve your lactate clearance and push threshold up.

Integrate these types of sessions into your training, and before long, you should see a performance improvement and a nice shift in your lactate curve as your clearance and threshold improve.

If you’re interested in doing a lactate test, we’d love to see you in our lab. You can see our schedule and easily book online here.

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Head CoachBen PulhamBen Pulham is the founder of Coached, a personal training programme that helps runners & triathletes optimise, track and enjoy their training.