Which nutrient is the body's primary source of energy during high-intensity exercise?

Carbohydrates are the body's primary source of energy during high-intensity exercise due to their ability to be rapidly converted into glucose, which fuels muscle activity. When engaging in exercises that require quick bursts of energy, such as sprinting or high-intensity interval training, the body relies predominantly on carbohydrates because they provide ATP (adenosine triphosphate) more efficiently compared to fats or proteins.

During high-intensity workouts, the demand for energy is high, and carbohydrates can be metabolized anaerobically (without oxygen) through the glycolytic pathway, allowing for immediate energy production. This process is particularly effective in sustaining intense muscular contractions over short periods, making carbohydrates essential for performance in activities that require quick, explosive movements.

In contrast, while fats are a valuable energy source for lower-intensity or endurance exercises, they take longer to break down for energy use. Proteins primarily serve as building blocks for tissues and are not typically used as a primary energy source unless in prolonged exercise or fasting conditions. Water, while crucial for hydration and physiological functions, does not provide energy and therefore does not contribute to energy production during exercise.