Approximately how long does it take for an athlete to deplete glycogen content in the liver during strenuous exercise?

• A. 1 hour
• B. 2 hours
• C. 3 hours
• D. 4 hours

Answer: (B)

Glycogen depletion during strenuous exercise is a critical aspect of understanding energy sources for athletes. The liver glycogen content typically starts to deplete significantly during extended periods of high-intensity exercise. Research suggests that it generally takes around two hours of vigorous exercise for liver glycogen stores to be significantly reduced.

During this time, glucose released from liver glycogen plays a crucial role in maintaining blood glucose levels and providing energy to working muscles. Factors such as exercise intensity, the athlete's initial glycogen stores, and their conditioning level all influence how quickly glycogen is utilized. Two hours represents a balanced estimate that aligns with physiological studies, highlighting the importance of glycogen availability for sustained athletic performance.