If during those 30 minutes you consume adequate fluids, protein and carbohydrate amounts, you will repair your muscle fibers, helping them to grow strong, stay and recover to be ready for the next workout. If you wait more than 30 minutes, your body will already produced cortisol, a hormone that causes accumulation of fat in the torso and muscle atrophy. Also during these 30 minutes, your body will replenish glycogen in your muscles, so it is essential to consume enough carbohydrates. ©