Carbohydrates (carbs) are the main fuels for the brain and for the body during intense muscular exercise, such as bodybuilding, sprinting, throwing and boxing. The cells get carbs from blood sugar, stored glycogen and by converting amino acids, lactic acid, and pyruvic acid
into new blood sugar in the liver. Low glycogen or blood sugar levels cause fatigue and poor physical performance.
Consuming carb drinks during endurance exercise prevents fatigue and reduces the perception of effort. Researchers from the University of / North Carolina found consuming carb drinks didn't reduce the perception of effort during weight training. The subjects in the experimental groups lifted weights for two hours and drank a carbohydrate beverage (six percent carbohydrate) or placebo beverages during the resistance-training bout.
Carbohydrate supplementation may speed recovery from repeated workouts but didn't affect a single training session.