AFAA Personal Trainer Certification Practice Exam 2026 - Free Personal Trainer Practice Questions and Study Guide

Lactic acid plays a crucial role in the body's energy metabolism, especially during intense exercise. After it is produced in the muscles as a byproduct of anaerobic respiration, it does not simply accumulate or sit idle. Instead, the liver takes charge of processing lactic acid through a process called gluconeogenesis, where it is converted back into glucose. This is significant because the glucose can then be reused by the muscles for energy or returned to the bloodstream, thereby helping to restore energy levels and support continued physical activity.

This conversion is essential for maintaining energy balance, particularly during prolonged exercise when the demand for energy exceeds the supply of oxygen available to the muscles. The ability of the liver to convert lactic acid into glucose reinforces the body's efficient handling of metabolites produced during intense workouts, supporting endurance and performance over time.