Which nutrient is the primary source of energy during prolonged exercise?

The primary source of energy during prolonged exercise is complex carbohydrates. These carbohydrates are made up of long chains of sugar molecules, which provide a steady and sustained release of glucose into the bloodstream. This gradual release is essential during extended periods of physical activity because it helps maintain energy levels over time, delaying fatigue.

Complex carbohydrates are found in foods such as whole grains, legumes, and vegetables. They not only supply energy but also offer important nutrients and fiber that contribute to overall health. As exercise continues over a long duration, the body primarily relies on glycogen stores derived from these carbohydrates for energy, making them crucial for endurance activities.

In contrast, while fats can also be utilized for energy, especially during lower-intensity activities, complex carbohydrates remain the dominant source during sustained high-intensity exercise. Simple carbohydrates provide quick bursts of energy but are not as effective for prolonged energy needs. Proteins serve more as a building block for muscle repair and recovery rather than a significant source of energy during exercise. Hence, complex carbohydrates are the most efficient fuel for longer workouts.