Glycogen, is simply carbohydrate stored in the muscle that is commonly called animal starch. It is the convertion process that changes into glucose (blood sugar) when your body requires energy. With low glycogen levels your energy levels can suffer. This is a common result of a low carbohydrate diet followed for a long period of time. Without glycogen and glucose you could not workout with the intensity required to meet your goals and expectations. When you wake up in the morning you are generally somewhat depleted of glycogen and glucose. Therefore, higher amounts of carbohydrates are needed to raise your levels of glycogen and glucose to give you the energy needed to get you through the day.
About an hour before a workout it is recommended that you consume some form of complex carbohydrates to assure the energy you will need to workout.Click here for more info