METABOLISM OF SUGARS AND PHYSICAL PERFORMANCE

Physical activity in the form of exercise requires the metabolism of b odily fuel reserves to provide energy for muscle contraction. Under no rmal circumstances, very little protein is metabolized to provide the energy for muscle contraction. At rest and at low exercise intensities , the metabolism of fat provides a considerable proportion of the ener gy for resting metabolic processes and muscle contraction. However, at exercise intensities at which athletes train and compete, the metabol ism of bodily carbohydrate reserves (eg, blood glucose and liver and m uscle glycogen) provides the predominant: fuel for muscle contraction. Furthermore, when these substrates reach critically low amounts or ar e decreased by some amount, fatigue occurs. There is a significant bod y of literature examining the effects of ingestion of various types of sugars at various times during exercise and during recovery from exer cise on carbohydrate fuel reserves and on physical performance.