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Hypoglycemia, or low blood sugar, is most common in people who have diabetes. If you have already been diagnosed with diabetes and need more information about low blood sugar, see the topics:
What is low blood sugar?
You may have briefly felt the effects of low blood sugar when you've gotten really hungry or exercised hard without eating enough. This happens to nearly everyone from time to time. It's easy to correct and usually nothing to worry about.
But low blood sugar, or hypoglycemia, can also be an ongoing problem. It occurs when the level of sugar in your blood drops too low to give your body energy.
What causes hypoglycemia in people who don't have diabetes?
Ongoing problems with low blood sugar can be caused by:
- Diseases of the liver, kidneys, or pancreas.
- Metabolic problems.
- Alcohol use.
- Stomach surgery.
What are the symptoms?
Symptoms can be different depending on how low your blood sugar level drops.
- Mild hypoglycemia can make you feel hungry or like you want to vomit. You could also feel jittery or nervous. Your heart may beat fast. You may sweat. Or your skin might turn cold and clammy.
- Moderate hypoglycemia often makes people feel short-tempered, nervous, afraid, or confused. Your vision may blur. You could also feel unsteady or have trouble walking.
- Severe hypoglycemia can cause you to pass out. You could have seizures. It could even cause a coma or death.
If you've had hypoglycemia during the night, you may wake up tired or with a headache. And you may have nightmares. Or you may sweat so much during the night that your pajamas or sheets are damp when you wake up.
How is hypoglycemia diagnosed?
To diagnose hypoglycemia, your doctor will do a physical exam and ask you questions about your health and any medicines you take. You will need blood tests to check your blood sugar levels. Some tests might include not eating (fasting) and watching for symptoms. Other tests might involve eating a meal that could cause symptoms of low blood sugar several hours later. The results of these types of tests can help diagnose the cause.
You may also need tests to look for or rule out health problems that could be affecting your blood sugar levels.
How is it treated?
You can treat a sudden episode of low blood sugar by eating or drinking something with sugar in it. Some examples of "quick-sugar foods" are fruit juice, soda, milk, raisins, and hard candy. You may also take glucose tablets. This is usually all that's needed to get your blood sugar level back up in the short term.
If your hypoglycemia is caused by a health condition, you may need treatment for that condition. There also may be steps you can take to avoid low blood sugar. For example, talk to your doctor about whether changes in your diet, medicines, or exercise habits might help.
What should you do in an emergency?
If mild or moderate hypoglycemia isn't treated right away, it can turn into severe hypoglycemia. People with severe hypoglycemia usually pass out. If you pass out, someone should call 911 right away.
If you have a health problem that tends to cause low blood sugar, it's a good idea to teach your family, friends, and coworkers about what symptoms to watch for and what to do. You may also want to wear a medical alert bracelet or necklace.
Other Works Consulted
- Cryer PE (2011). Hypoglycemia. In S Melmed et al., eds., Williams Textbook of Endocrinology, 12th ed., pp. 1552–1577. Philadelphia: Saunders.
- Cryer PE, Davis SN (2015). Hypoglycemia. In DL Kasper et al., eds., Harrison's Principles of Internal Medicine, 19th ed., vol. 2, pp. 2430–2435. New York: McGraw-Hill Education.
- Endocrine Society (2009). Evaluation and management of adult hypoglycemic disorders: An endocrine society clinical practice guideline. Journal of Clinical Endocrinology and Metabolism, 94(3): 709–728. Available online: http://www.endo-society.org/guidelines/final/upload/FINAL-Standalone-Hypo-Guideline.pdf.
- Masharani U, Gitelman SE (2011). Hypoglycemic disorders. In DG Gardner, D Shoback, eds., Greenspan's Basic and Clinical Endocrinology, 9th ed., pp. 657–674. New York: McGraw-Hill.
- Murray MT (2013). Hypoglycemia. In JE Pizzorno, MT Murray, eds., Textbook of Natural Medicine, 4th ed., pp. 1464–1472. St. Louis: Elsevier.
Current as of: July 28, 2019
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Matthew I. Kim MD - Endocrinology