This post-exercise response is also known as biochemical or metabolic supercompensation. High levels of these same hormones are also necessary to restore the negative metabolic effect created by catecholamines and glucocorticoids produced during exercise. Testosterone usually appears again during later phases of post-workout recovery. These increases in turn, have been shown to further increase protein synthesis and muscle growth after a bout of exercise as well as increasing the uptake of amino acids. By adding amino acids after exercise we have further increased the available free amino acid pool as well.
Amino acids are necessary for protein synthesis to take place.
So without the insulin rebound after exercise, the body would remain in a catabolic state. Let s examine more closely why it is suggested that carbohydrate be taken with protein immediately following a bout if exercise. We know that with the onset of exercise, ATP is the immediate source of energy. As the exercise progresses, the ATP stores are reduced and glycogen and glucose are also utilized by the muscle for fuel. With more muscle glycogen and glucose being used for energy, blood glucose levels soon begin to drop.