Maintaining a normal range of blood sugar, known as glucose, is important for healthy cells throughout the body. The American Association for Clinical Chemistry defines a normal blood sugar level between 70 and 99 mg/dL. Elevated levels occur most commonly with diabetes, and long-term effects on the body can be serious.
Maintaining Normal Blood Sugar
Glucose in the blood is a product of digestion from carbohydrates in the diet. Insulin moves glucose into the cells where it provides calories for energy. Excess is stored in the liver as glycogen for use over the next few hours, or converted to fat and stored indefinitely. When blood sugars dip below normal, a hormone called glucagon releases glucose from stored glycogen to raise blood levels. When the blood sugar level goes above normal--as is typical after a meal--the pancreas sends out insulin to push glucose into cells for energy or into storage as glycogen.
Low Blood Sugar
Lab Tests Online lists conditions that can cause sugar levels to run low, a state called hypoglycemia. These include adrenal insufficiency, severe liver disease, hypopituitarism, hypothyroidism and insulinomas. Hypoglycemia also is seen after going without food for an extended period of time. Symptoms include sweating, hunger and dizziness followed by confusion and eventually coma and death if untreated. Primary hypoglycemia (having no known cause) is rare. Reactive hypoglycemia occurs as a response to a high carbohydrate meal and is more common. For this condition, sugar levels are normalized with small, frequent meals that contain a substantial source of protein and fat.
High Blood Sugar
A high blood sugar level is seen in Cushing's syndrome, hyperthyroidism, acute and severe physical stresses and as a side effect of some medications. Most commonly it is seen in diabetes, a disorder of insulin production or function. Diabetes is diagnosed with fasting blood sugar levels to prevent food from affecting results. Medline Plus classifies levels between 100 and 126 mg/dL as prediabetes and levels above 126 mg/dL as diagnostic of diabetes. Symptoms include excessive thirst and frequent urination as the body flushes out glucose through the kidneys. Fatigue and weight loss occur because glucose cannot get into the cells to be used for energy.
Long Term Effects of High Blood Sugar
Glucose elevation affects every system through which blood travels in the body. Damage to eye tissue leads to blindness, kidney failure results from long-term exposure to high amounts of glucose and nerve damage causes pain, ulcers and death of cells in the extremities. Large blood vessel damage increases risk of heart attack and stroke. To avoid these complications in diabetes, maintaining normal glucose levels is emphasized.
Blood Sugar Monitoring
Responding with appropriate treatment--food, medication or exercise--helps blood sugar control. Anyone can monitor blood sugar levels several times a day with simple home testing kits. Laboratories can run a test called A1C, which reflects blood glucose levels over the past two to three months. Together, these tests show how effective a treatment plan is working and can help control long-term outcome.
