Have you heard of the lactate threshold, aerobic threshold, or anaerobic threshold? In this blog, I want to explain what each of these terms means and how you can evaluate them to know at what paces you should train and compete.

What Is the Lactate Threshold?

The lactate threshold is the intensity at which the rate of lactate production and clearance (its use for energy production) is no longer equal, leading to the accumulation of lactate concentration in the blood. This has nothing to do with the onset of fatigue, as we’ll discuss in future posts—lactate is not the cause of fatigue, but rather an indicator of what is happening in the body. The lactate threshold is also traditionally known as the “aerobic threshold,” although the terms aerobic and anaerobic are often used incorrectly.

The lactate threshold is considered a very good predictor of performance in endurance sports. It indicates the percentage of VO2max at which an athlete can compete in long-distance events. Sometimes it’s beneficial to bring this threshold closer to VO2max, while other times, increasing VO2max is necessary to continue raising the lactate threshold (raising the athlete’s ceiling).

Another commonly used term is OBLA. There are intensities at which lactate levels rise, but if we maintain that intensity, lactate stabilizes at certain levels and doesn’t continue to increase. The point at which lactate continues to rise even if intensity remains stable is called OBLA (Onset of Blood Lactate Accumulation), often incorrectly referred to as the “anaerobic threshold.” This point typically occurs at around 4 mmol of lactate concentration in the blood.

How Can I Measure the Lactate Threshold?

The most effective way to measure your lactate thresholds is through an incremental test using a lactate analyzer. You will perform stages of at least 2 minutes at each intensity, at the end of which a lactate analysis will be conducted.

The intensity at which blood lactate concentration begins to rise steadily will indicate the first lactate threshold. The intensity at which lactate increases exponentially (around 4 mmol) will mark the second lactate threshold or OBLA.

If you don’t have access to a lactate analyzer, one way to predict OBLA (commonly used in cycling, such as with the FTP test) is to perform either a 1-hour test or a 20-minute test and multiply the result by 0.95. These tests should be conducted at the highest constant intensity the athlete can maintain for that duration.

How Can I Improve My Lactate Threshold?

The lactate threshold, like running economy, is highly trainable. The first threshold can be improved by accumulating time at intensities below it. The second threshold can be improved through long HIIT sessions (e.g., at 90% of VO2max) or interval training at OBLA intensity.

I hope this has clarified these commonly used yet often misunderstood concepts.

If you want help improving your running performance and reducing injuries, you can visit this page where I explain how I can assist you.

Best regards, and happy running!