Which energy system is predominantly utilized during prolonged, moderate-intensity exercise?

The correct choice highlights the aerobic glycolysis energy system, which plays a central role during prolonged, moderate-intensity exercise. This system is characterized by the body's ability to utilize oxygen to produce ATP through the breakdown of carbohydrates. It becomes the dominant energy source when exercise duration extends beyond a few minutes, particularly at moderate intensities where the demand for energy is sustained while still allowing for sufficient oxygen delivery.

During such activities, like long-distance running or cycling, the body effectively mobilizes glycogen stores, converting glucose to pyruvate via glycolysis, and then further to ATP in the presence of oxygen. This results in a steady and reliable supply of energy, essential for maintaining endurance over longer periods.

While fat oxidation is also an important energy source during prolonged exercise, especially at lower intensities, aerobic glycolysis provides a quicker release of energy compared to fat oxidation, making it a more efficient pathway during moderate efforts. The phosphagen system predominantly supplies energy for short bursts of high-intensity activity (about 10 seconds or less), and anaerobic glycolysis kicks in predominantly during high-intensity efforts that last a little longer, typically up to 2 minutes.

Understanding these distinctions is crucial for recognizing how the body adapts its energy production methods based on the