Carbohydrates
Carbohydrates are your body's preferred source of fuel during moderate to high-intensity exercise. They are stored primarily as muscle glycogen and liver glycogen before being converted into glucose to produce energy.
As exercise duration increases, glycogen stores gradually become depleted. Once these stores begin to run low, performance typically declines, perceived effort increases, and fatigue develops rapidly.
Replacing carbohydrates during exercise helps maintain energy availability, preserve glycogen stores, and sustain performance over longer durations.