What is the primary source of energy for muscles during exercise?

The primary source of energy for muscles during exercise comes from carbohydrates, fats, and proteins. During physical activity, the body predominantly relies on carbohydrates and fats for energy production. Carbohydrates, stored as glycogen in muscles and the liver, are utilized swiftly during high-intensity activities, while fats serve as a crucial energy source during prolonged, lower-intensity exertion. Proteins can be used for energy, but they primarily serve other roles such as muscle repair and growth.

In contrast, vitamins, minerals, and water play essential supporting roles in energy production and overall health, but they do not serve as direct energy sources. Vitamins assist in metabolic processes but do not provide calories, minerals contribute to various physiological functions, and water is vital for hydration and maintaining physiological balance but does not supply energy. Thus, the combination of carbohydrates, fats, and proteins is essential for fueling muscle activity during exercise.