Sugar serves as a primary energy source during physical activity, particularly in the form of glucose. When exercising, muscles utilize glucose stored as glycogen for quick energy. While sugar in moderation can enhance performance, excessive intake may lead to energy crashes and negatively impact endurance. Additionally, the type of sugar consumed can influence workout outcomes; for instance, complex carbohydrates provide sustained energy compared to simple sugars. Thus, understanding the role of sugar helps optimize energy levels and workout performance, making nutrition an essential aspect of training.