The Canadian Diabetes Association suggests maintaining blood sugar or glucose levels between 4 millimoles per liter and 11 millimoles per liter. When blood sugar levels drop or rise outside of that range, symptoms of low or high blood glucose occur.
Symptoms of low blood glucose levels include shakiness, irritability, confusion, hunger and a lightheaded feeling, according to the Canadian Diabetes Association. Eating or drinking high-carbohydrate foods and fluids quickly raises the blood sugar levels in most cases. High blood glucose levels cause thirstiness, frequent urination and drowsiness. Frequent high glucose readings require an adjustment to the patient's diabetes treatment plan. A blood glucose meter is the best way to keep track of blood sugar levels.