How is the lactate threshold defined?

The lactate threshold is defined as the point during exercise at which lactate starts to accumulate in the blood faster than it can be removed. This threshold is significant because it represents a transition from aerobic to anaerobic metabolism, marking the intensity beyond which exercise can only be sustained for a limited duration. It is often described as a boundary between sustainable and unsustainable levels of exercise intensity.

For practical application, the lactate threshold is typically identifiable as the exercise intensity that an individual can maintain for about 30 to 60 minutes, which would result in them being exhausted at the end of that time 1. It is also represented by an inflection point where lactate begins a higher rate of accumulation in the bloodstream during gradually increasing exercise intensity 1.

This concept of lactate threshold is pivotal for athletes, particularly in endurance sports, to optimize their performance by training at or near this threshold to enhance their ability to sustain high-intensity efforts for longer 2.