Sugar can significantly affect energy levels during exercise. Consuming simple sugars can lead to a quick spike in blood glucose, providing immediate energy. However, this can be followed by a rapid drop in energy, causing fatigue and decreased performance. In contrast, complex carbohydrates offer a more stable and sustained energy release. It's essential to balance sugar intake before physical activities for optimal performance. Careful management of sugar consumption during workouts can help in maintaining endurance and prevent energy crashes, contributing to overall exercise effectiveness.