If you exercise in the morning, get up early enough to eat breakfast. That may mean one to two hours before your workout. Most of the energy you got from dinner the previous night is used up by morning, and your blood sugar may be low. If you don't eat, you may feel sluggish or lightheaded when you exercise. If you plan to exercise within an hour after breakfast, eat a lighter breakfast or drink something to raise your blood sugar, such as a sports drink.