What role does the liver play in exercise metabolism?

The liver plays a critical role in exercise metabolism primarily by regulating blood glucose levels. During physical activity, maintaining adequate blood glucose concentrations is essential to provide a stable energy source for working muscles. The liver achieves this through several mechanisms, including glycogenolysis (the breakdown of glycogen into glucose) and gluconeogenesis (the synthesis of glucose from non-carbohydrate sources).

As exercise begins and increases in intensity, the liver helps to ensure that glucose is available for rapid use by muscle cells. When glucose levels drop, especially during prolonged exercise, the liver releases glucose into the bloodstream to meet the energy demands of muscles. This regulation is vital for sustaining exercise performance and preventing fatigue.

In contrast, the other choices do not accurately capture the liver's contribution. While the liver does store carbohydrates (glycogen), it is not limited to only storing them; it also plays an active role in releasing glucose when needed. The liver does not produce oxygen; this process primarily occurs in the lungs. Lastly, the idea that the liver does not play a role in exercise metabolism ignores its essential functions in energy regulation and overall metabolic control during exercise.