Symptoms of High Blood Sugar
Mild high blood sugar
If your blood sugar levels are consistently 200 milligrams per deciliter (mg/dL) to 350 mg/dL, you may have mild symptoms of high blood sugar. You may urinate more than usual if you are drinking plenty of liquids. Some people with diabetes may not notice any symptoms when their blood sugar level is in this range. The main symptoms of high blood sugar are:
- Increased thirst
- Increased urination
- Weight loss
- Fatigue
- Increased appetite
Young children are unable to recognize symptoms of high blood sugar. Parents need to do a home blood sugar test on their child whenever they suspect high blood sugar.
If you have diabetes, it's important to avoid getting the flu. Flu, or influenza, is a viral infection of the respiratory system and muscles. While everyone has a chance of catching flu, having diabetes makes it harder to fight off viruses that cause flu. Flu and other viral infections can create added stress in your body, which can affect your blood sugar levels and increase the chance of serious health complications.
Read the Diabetes and the Flu article > >
If you do not drink enough liquids to replace the fluids lost from high blood sugar levels, you can become dehydrated. Young children can become dehydrated very quickly. Symptoms of dehydration include:
- A dry mouth and increased thirst.
- Warm, dry skin.
Moderate to severe high blood sugar
If your blood sugar levels are consistently high (usually above 350 mg/dL), you may have moderate to severe symptoms of high blood sugar. These symptoms include:
- Blurred vision
- Extreme thirst
- Lightheadedness
- Flushed hot dry skin
- Restlessness, drowsiness, or difficulty waking up
If your body produces little or no insulin (people with type 1 diabetes and some people with type 2 diabetes), you also may have the following symptoms:
- Rapid, deep breathing
- A fast heart rate and a weak pulse
- A strong, fruity breath odor
- Loss of appetite, abdominal pain, and/or vomiting
If your blood sugar levels continue to rise, you may become confused and lethargic. You also may become unconscious if your blood sugar levels are very high.
WebMD Medical Reference from Healthwise

