Hyperglycemia, or high blood sugar, occurs when your body doesn't have enough insulin or doesn't use insulin effectively. Chronic high blood sugar can cause serious health complications because it weakens blood vessels. Smaller blood vessels can rupture, leading to nerve damage, blindness and kidney disease.
If you often have high blood sugar levels, talk to your doctor: You might need an adjustment in diet or diabetes medication.
Pre- and Post-Prandial Glucose Levels
If you have diabetes, you're probably checking your blood sugar levels before eating -- a preprandial reading -- and after meals -- a postprandial reading. Before you eat, your blood sugar should be between 70 and 130 mg/dl. Although it's normal for blood sugar levels to rise after eating, according to the American Diabetes Association, blood sugar levels should return to less than 180 mg/dl within two hours after eating.
Reasons for High Blood Sugar
If your blood sugar levels remain high four hours after eating, it might be caused by eating too much food, specifically too many carbohydrates, or not taking enough insulin. If you're normally physically active, missing an exercise session can cause higher than normal blood sugar. Illness, infection and stress also can raise blood sugar, even though your food and insulin intakes were right on target. You might have high blood sugar levels four hours after eating if your blood sugar levels were too high before eating.
Lowering Blood Sugar Levels
If your blood sugar levels remain too high, take a supplemental dose of insulin. If you don't take insulin, you can exercise, which will help your body use excess glucose. Avoid high blood sugars by limiting high-glycemic carbohydrates, which have an immediate impact on glucose levels. Harvard's Joslin Diabetes Center recommends eating a high-fiber diet and states that "people with diabetes who ate 50 grams of fiber a day --- particularly soluble fiber --- were able to control their blood glucose better than those who ate far less."
Ketones
If your blood sugar is above 240 mg/dl, have your urine checked for ketones, an acidic byproduct of burning fat rather than glucose for energy. If ketones build up in your bloodstream, you run the risk of developing ketoacidosis, a potentially fatal condition that might lead to a diabetic coma and death. If ketones are present in your urine, do not exercise to lower your blood sugar level. Often exercise can have the opposite effect, burning more fat and producing even more ketones. Other symptoms of ketoacidosis include shortness of breath, dry mouth, nausea and vomiting. If you suspect you have ketoacidosis, seek immediate medical attention.
