What’s the difference between hypoglycemia and hyperglycemia?

Medically reviewed by Sally Chao, MD. Last updated on Sep 27, 2024.

Official Answer by Drugs.com

Hypoglycemia means low blood sugar and is usually defined as a blood sugar less than 70 mg/dL.
Hyperglycemia means high blood sugar and is usually defined as blood sugar greater than 125 mg/dL in a person who has not eaten in the last eight hours or more than 180 mg/dL in someone who ate two hours ago.

Diabetes is a common cause of hyperglycemia, but not everyone who has hyperglycemia has diabetes. Hypoglycemia can occur as a side effect of taking insulin for diabetes, but other people may develop hypoglycemia, too.

	Hypoglycemia	Hyperglycemia
Definition	Blood sugar less than 70 mg/dL	Fasting blood sugar of more than 125 mg/dL or more than 180 mg/dL two hours after eating
Symptoms	Feeling jittery, tired or dizzy Being hungry, irritable or confused Having a headache Slurring your words	Extreme thirst Dry mouth Weakness Headache Frequent urination Blurry vision Nausea Confusion Shortness of breath
Causes	Skipping meals or fasting Too much insulin Binge drinking alcohol	Diabetes

Mild levels of hypoglycemia can be treated by eating something that contains carbohydrates. If not treated promptly, hypoglycemia can result in seizures or losing consciousness. If a person has lost consciousness because of low blood sugar and therefore cannot eat or drink, then a drug called glucagon can be given.

Hyperglycemia from undiagnosed diabetes can become life-threatening.

If you experience symptoms of either too high or too low blood sugar, seek medical evaluation.

How your body balances glucose

Glucose is a major source of energy for your body. The level of glucose in your blood will go up and down over the course of a day depending on when and what you have eaten and how much activity you are performing. A healthy human body regulates the amount of glucose in the blood within a range of values considered normal.

Your pancreas and liver are both involved in maintaining this balance. Under normal circumstances, when you eat, your pancreas releases the hormone insulin, which helps your body use the energy created from the food you eat. If your body doesn't need the energy right away, it can store it as glycogen in the liver. When your body needs energy, signaled by a decrease in blood sugar, your pancreas releases glucagon. The presence of glucagon tells your liver to release the stored glycogen so that your body can use it for energy.

References

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hypoglycemia. July 2021. Available at: https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/low-blood-glucose-hypoglycemia. [Accessed September 20, 2021].
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Managing Diabetes. December 2016. Available at: https://www.niddk.nih.gov/health-information/diabetes/overview/managing-diabetes. [Accessed September 20, 2021].
Hantzidiamantis PJ, Lappin SL. Physiology, Glucose. StatPearls. 2021 Jan. https://www.ncbi.nlm.nih.gov/books/NBK545201/.

What foods should I eat or avoid for hypoglycemia?

If you have diabetes, then you will know that certain foods can significantly affect your blood sugar levels. There is no one-size-fits-all meal plan for people with diabetes, but it can be confusing knowing what you can and can’t eat. Some examples of nutritionally high dinners suitable for people at risk of hypoglycemia include: soup, such as lentil and quinoa; grilled fish with broccoli, peas, and sweet potato; broccoli salad with artichokes, black beans, and sun-dried tomatoes; chicken vege stir fry with zucchini, carrots, and broccoli; and vegetarian lentil tacos. Continue reading

Can you have hypoglycemia without diabetes?

Yes, people without diabetes can have hypoglycemia, also called low blood sugar, but it is not very common. Hypoglycemia occurs most frequently in people with diabetes. Continue reading

Does metformin cause hypoglycemia?

Metformin rarely produces hypoglycemia (low blood sugar levels) because it does not change how much insulin is secreted by the pancreas and does not cause high insulin levels. But metformin toxicity or overdosage that causes lactic acidosis has been associated with hypoglycemia. Experts believe the cause may be increased glucose consumption due to anaerobic metabolism, coupled with decreased oral intake of food and carbohydrates, decreased liver glucose production, and decreased glucose absorption. Continue reading

What’s the difference between hypoglycemia and hyperglycemia?

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