How is lactate formed during exercise?

Lactate is primarily formed during high-intensity exercise when the demand for energy exceeds the oxygen supply available for aerobic metabolism. In this anaerobic environment, the body relies on the glycolysis pathway to generate ATP quickly. When glucose is broken down, it is converted to pyruvate. However, in the absence of sufficient oxygen, pyruvate is not fully oxidized through the aerobic pathway. Instead, it undergoes a process known as fermentation, where it is converted into lactate.

This conversion enables the continued production of ATP even under anaerobic conditions, although it is less efficient than aerobic metabolism. As intensity increases and oxygen becomes limited, the accumulation of lactate can lead to muscle fatigue, highlighting its role in energy production during brief, intense exercise.