What physical benefit do carbohydrates provide during prolonged exercise?

Carbohydrates play a crucial role in providing sustained energy during prolonged exercise, making the chosen answer accurate. During activities that require endurance, such as running or cycling, the body primarily relies on carbohydrates stored in muscles and the liver (in the form of glycogen) for energy. As exercise continues over an extended period, particularly beyond 60-90 minutes, carbohydrate availability becomes essential to maintain performance levels and delay fatigue.

When carbohydrates are ingested before or during exercise, they help to replenish glycogen stores, ensuring that the body can continue to perform at optimal levels. Unlike fats, which are also a source of energy, carbohydrates are more readily accessible for quick bursts of energy, making them ideal for sustaining performance over long durations.

In contrast, the other options presented do not correctly express the role of carbohydrates during prolonged exercise. For instance, carbohydrates do not increase lactic acid levels directly; rather, they help manage how the body utilizes energy, affecting lactic acid production indirectly. They also do not enhance muscle strength directly, as muscle strength is more associated with resistance training and is influenced by factors like protein intake and training regimen. Lastly, carbohydrates do not slow down metabolism; instead, they provide energy that can elevate metabolic activities during exercise.