Elsevier Logo




Learn more about our Patient Engagement products now! Turn your patients into active participants in their healthcare by giving them easy access to the same evidence-based information you trust – but delivered in an easy-to-understand format.

 Preventing Hypoglycemia

Preventing Hypoglycemia

Hypoglycemia occurs when the level of sugar (glucose) in the blood is too low. Hypoglycemia can happen in people who do or do not have diabetes (diabetes mellitus). It can develop quickly, and it can be a medical emergency. For most people with diabetes, a blood glucose level below 70 mg/dL (3.9 mmol/L) is considered hypoglycemia.

Glucose is a type of sugar that provides the body's main source of energy. Certain hormones (insulin and glucagon) control the level of glucose in the blood. Insulin lowers blood glucose, and glucagon increases blood glucose. Hypoglycemia can result from having too much insulin in the bloodstream, or from not eating enough food that contains glucose.

Your risk for hypoglycemia is higher:
  • If you take insulin or diabetes medicines to help lower your blood glucose or help your body make more insulin.
  • If you skip or delay a meal or snack.
  • If you are ill.
  • During and after exercise.

You can prevent hypoglycemia by working with your health care provider to adjust your meal plan as needed and by taking other precautions.

How can hypoglycemia affect me?

Mild symptoms

Mild hypoglycemia may not cause any symptoms. If you do have symptoms, they may include:
  • Hunger.
  • Anxiety.
  • Sweating and feeling clammy.
  • Dizziness or feeling light-headed.
  • Sleepiness.
  • Nausea.
  • Increased heart rate.
  • Headache.
  • Blurry vision.
  • Irritability.
  • Tingling or numbness around the mouth, lips, or tongue.
  • A change in coordination.
  • Restless sleep.

If mild hypoglycemia is not recognized and treated, it can quickly become moderate or severe hypoglycemia.

Moderate symptoms

Moderate hypoglycemia can cause:
  • Mental confusion and poor judgment.
  • Behavior changes.
  • Weakness.
  • Irregular heartbeat.

Severe symptoms

Severe hypoglycemia is a medical emergency. It can cause:
  • Fainting.
  • Seizures.
  • Loss of consciousness (coma).
  • Death.

What nutrition changes can be made?

  • Work with your health care provider or diet and nutrition specialist (dietitian) to make a healthy meal plan that is right for you. Follow your meal plan carefully.
  • Eat meals at regular times.
  • If recommended by your health care provider, have snacks between meals.
  • Do not skip or delay meals or snacks. You can be at risk for hypoglycemia if you are not getting enough carbohydrates.

What lifestyle changes can be made?

  • Work closely with your health care provider to manage your blood glucose. Make sure you know:
    • Your goal blood glucose levels.
    • How and when to check your blood glucose.
    • The symptoms of hypoglycemia. It is important to treat it right away to keep it from becoming severe.
  • Do not drink alcohol on an empty stomach.
  • When you are ill, check your blood glucose more often than usual. Follow your sick day plan whenever you cannot eat or drink normally. Make this plan in advance with your health care provider.
  • Always check your blood glucose before, during, and after exercise.

How is this treated?

This condition can often be treated by immediately eating or drinking something that contains sugar, such as:
  • Fruit juice, 4–6 oz (120–150 mL).
  • Regular (not diet) soda, 4–6 oz (120–150 mL).
  • Low-fat milk, 4 oz (120 mL).
  • Several pieces of hard candy.
  • Sugar or honey, 1 Tbsp (15 mL).

Treating hypoglycemia if you have diabetes

If you are alert and able to swallow safely, follow the 15:15 rule:
  • Take 15 grams of a rapid-acting carbohydrate. Talk with your health care provider about how much you should take.
  • Rapid-acting options include:
    • Glucose pills (take 15 grams).
    • 6–8 pieces of hard candy.
    • 4–6 oz (120–150 mL) of fruit juice.
    • 4–6 oz (120–150 mL) of regular (not diet) soda.
  • Check your blood glucose 15 minutes after you take the carbohydrate.
  • If the repeat blood glucose level is still at or below 70 mg/dL (3.9 mmol/L), take 15 grams of a carbohydrate again.
  • If your blood glucose level does not increase above 70 mg/dL (3.9 mmol/L) after 3 tries, seek emergency medical care.
  • After your blood glucose level returns to normal, eat a meal or a snack within 1 hour.

Treating severe hypoglycemia

Severe hypoglycemia is when your blood glucose level is at or below 54 mg/dL (3 mmol/L). Severe hypoglycemia is a medical emergency. Get medical help right away.

If you have severe hypoglycemia and you cannot eat or drink, you may need an injection of glucagon. A family member or close friend should learn how to check your blood glucose and how to give you a glucagon injection. Ask your health care provider if you need to have an emergency glucagon injection kit available.

Severe hypoglycemia may need to be treated in a hospital. The treatment may include getting glucose through an IV. You may also need treatment for the cause of your hypoglycemia.

Where to find more information

Contact a health care provider if:

  • You have problems keeping your blood glucose in your target range.
  • You have frequent episodes of hypoglycemia.

Get help right away if:

  • You continue to have hypoglycemia symptoms after eating or drinking something containing glucose.
  • Your blood glucose level is at or below 54 mg/dL (3 mmol/L).
  • You faint.
  • You have a seizure.

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.).


  • Know the symptoms of hypoglycemia, and when you are at risk for it (such as during exercise or when you are sick). Check your blood glucose often when you are at risk for hypoglycemia.
  • Hypoglycemia can develop quickly, and it can be dangerous if it is not treated right away. If you have a history of severe hypoglycemia, make sure you know how to use your glucagon injection kit.
  • Make sure you know how to treat hypoglycemia. Keep a carbohydrate snack available when you may be at risk for hypoglycemia.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.