Causes and Risk Factors of Hypoglycemia

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Hypoglycemia (low blood sugar) occurs when your blood sugar (glucose) levels are less than or equal to 70 mg/dL and certain symptoms are present. It can be caused by a number of factors, depending on whether or not you also have diabetes.

hypoglycemia causes

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Here's what you need to know about the causes and risk factors of hypoglycemia:

Causes: People With Diabetes

If you have diabetes and take insulin or oral medications that stimulate insulin secretion, there are a number of factors that can cause hypoglycemia, including the following.

Lack of Carbohydrates

Carbs are the body's main source of glucose, so if you don't eat enough of them, your blood sugar may dip. This is especially possible if you reduce the number of carbs you're taking in but fail to adjust your medication accordingly.

Delaying or Skipping Meals

If you take insulin or oral medications for diabetes, eating a meal later than you planned or skipping it altogether can result in hypoglycemia. Make sure you talk to your healthcare provider about whether or not you should also skip your medication if you skip a meal.


Exercise is an essential component of a sound diabetes management strategy. It's great for helping to reduce your blood sugar levels, lose weight, burn calories, and have more energy.

If you have diabetes, however, and you exercise without eating, exercise more than you normally do, or you delay your meal, you may become hypoglycemic.

Make sure you take a snack along with you for before or after your workout, as well as a fast-acting source of carbohydrates like raisins, juice, or jellybeans, in case your blood sugar gets too low.

Medication Mishaps

Taking too much insulin or oral diabetes medication can cause hypoglycemia. Always take the dose specifically prescribed for you.

Not sticking to your medication schedule can also have a significant effect on blood sugar level. And if you don't give your healthcare provider an accurate sense of how you take your medication, they may prescribe higher doses to try and "manage" your high blood sugar.

If this happens and you then decide to take your medicine, you run the risk of hypoglycemia.

Drinking Alcohol

If you're taking insulin or an oral diabetes medication, drinking alcohol can cause hypoglycemia.

This doesn't mean that you can't enjoy alcoholic beverages, but you need to consume them safely and be careful about checking your blood sugar levels while you do.

Weight Loss

Losing weight can make you more sensitive to insulin, resulting in needing less or no medication. If you continue to take the same medication dose after losing weight you may experience hypoglycemia due to increased sensitivity.

Be sure to talk to your healthcare provider about potentially reducing your dose if you're losing weight.

Tight Blood Sugar Control

It's important to realize that the tighter your glucose control, the higher your risk of hypoglycemia, especially early in treatment.

If you're on tight glucose control, you need to be given the proper tools, knowledge, and support to avoid severe hypoglycemic episodes while continuing to maintain glucose levels in the target range.

Once in awhile, hypoglycemia is normal, but if it keeps happening, you should talk to your healthcare provider about steps to stop your blood sugar from dropping to emergency levels.

Kidney Disease

One complication of diabetes is kidney disease, which can result in your kidneys taking longer to clear insulin from your system. This can potentially result in hypoglycemia.

Causes: People Without Diabetes

Hypoglycemia is a rare condition in people without diabetes. If you don't have diabetes and you develop hypoglycemia, this indicates that something else is going on in your body.

Potential causes are discussed here.


Hypoglycemia can be caused by certain medications, especially in children or people with kidney failure.

Medications that have been associated with causing hypoglycemia include:

  • The antimalarial drug Qualaquin (quinine)
  • The antibiotic Zymaxid (gatifloxacin)
  • The antiarrhythmic drug cibenzoline
  • The antimicrobial drug Pentam (pentamidine)
  • The nonsteroidal anti-inflammatory drugs (NSAIDs) Indocin and Tivorbex (indomethacin)

Taking someone else's diabetes medication can also have this effect.

Drinking Too Much Alcohol

If you don't eat enough or don't eat at all and you drink an excessive amount of alcohol, especially over the course of a few days, you may become hypoglycemic.

The combination of too much alcohol and a lack of food can stop your liver from putting glucose into your blood, causing your blood sugar level to crash.

Critical Illnesses

Kidney disorders, severe hepatitis, long-term anorexia, malaria, and sepsis (a complication of getting an infection) are all illnesses that can potentially cause hypoglycemia.

Hormonal Deficiency

Adrenal disorders such as Addison's disease and certain pituitary disorders can cause hypoglycemia, as well as not having enough growth hormone in children.

Producing Too Much Insulin

Some people have an overproduction of insulin that can cause hypoglycemia. Certain tumors may cause this overproduction, as can enlarged and more numerous beta cells in the pancreas.

Insulin Autoimmune Syndrome

This is a rare condition in which your body makes antibodies that attack insulin, creating hypoglycemia. It can be part of another autoimmune disease or it can be caused by certain medications.

Reactive Hypoglycemia

Reactive hypoglycemia occurs within a few hours after eating meals.

Scientists aren't sure exactly what causes it, but it can happen to people who have had stomach surgery because food passes into the intestine too quickly.

It also occurs in other people too, perhaps due to an enzyme deficiency that makes it difficult for your body to break down food or having pre-diabetes, which can cause insulin to fluctuate.

Risk Factors

There are some risk factors that may increase your potential for developing hypoglycemia.

Certain Populations

Children with type 1 diabetes, the elderly, and people with hypoglycemia unawareness are at a higher risk of developing hypoglycemia.

Hypoglycemia unawareness can occur if you experience low blood sugars frequently, which can make your body desensitized to symptoms. The inability to feel symptoms such as sweating, shaking, increased heartbeat, anxiety, or hunger is dangerous because it can result in unconsciousness or even death.

If you experience hypoglycemia frequently, it's important to talk to your healthcare provider about it so you can get it under better control and avoid an emergency.

Taking Certain Medications

If you're taking certain medications for type 2 diabetes, such as sulfonylureas, insulin, or a combination of insulin and non-insulin injectables, you have a higher risk of hypoglycemia. Some pill combinations and certain non-diabetes medications can also increase the risk for low blood sugar.

Talk to your healthcare provider about when and how much of your medication to take so that you don't make an error in dosing. Don't take too much medication, and try to stick to a scheduled meal regimen to help keep your blood sugar regulated.


If you have diabetes and take insulin, smoking increases your risk of developing hypoglycemia. The nicotine in cigarettes, cigars, and pipes can cause low blood sugar, possibly because it changes your cells in such a way that they don't clear insulin as well or as quickly.

Premature Birth

When your baby is born prematurely, they are at increased risk of developing hypoglycemia in the days following birth, especially during the first 48 hours.

The reason for this is that when you're pregnant, you pass sugar to your baby through the umbilical cord. Toward the end of your pregnancy, your baby will begin to store up some of the sugar in their liver to use after birth. They'll get the rest of the sugar they need after birth from regular feedings of formula or breastmilk.

When your baby is born prematurely, the amount of sugar they've stored is lower than that of a full-term baby since the liver isn't fully developed. Since many preemies also have feeding difficulties at first, they may not be able to get the amount of glucose they need once they burn through the small amount of sugar they have stored.

Additional factors that can make the risk of hypoglycemia higher in preemies include:

  • Breathing difficulties
  • Difficulty maintaining body temperature
  • Infection
  • Feedings have to be delayed at first
  • The mother had diabetes while pregnant, creating too much insulin in your baby's blood
  • Any health condition that causes hypoglycemia

Though hypoglycemia can turn into a dangerous condition if untreated, it's usually temporary in preemies and treated quickly and effectively. There are some disorders that may cause long-term low blood sugar, but these are rare.

Frequently Asked Questions

  • How low is too low for blood sugar?

    Blood sugar that’s below 70 mg/dL is low and may trigger a hypoglycemia attack. To bring it up to normal levels, you may need to consume a high-sugar snack or take medication. If your blood sugar falls to 54 mg/dL or lower, you should call your healthcare provider and seek immediate emergency treatment.

  • What could put me at risk for hyperglycemia besides diabetes?

    You’re at risk if you have prediabetes, which is when your blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes. Other risk factors include stomach surgery, enzyme deficiencies, liver or kidney disorders, heart disease, a hormone imbalance, and a tumor that's producing hormones. 

  • How can I lower my risk of a hypoglycemic attack when I exercise?

    If you have diabetes and are taking insulin, you may need to reduce your dosage and increase the amount of carbohydrates you eat before exercise. You need to consider the type of exercise, how long you plan to work out, and the intensity of your routine. Then discuss with your healthcare provider how best to adjust your medication and diet.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Diabetes and Digestive and Kidney Diseases. Low blood glucose (hypoglycemia).

  2. Eckert-Norton M, Kirk S. Non-diabetic hypoglycemia. J Clin Endocrinol Metab. 2013;98(10):39A-40A. doi:10.1210/jc.2013-v98i10-39A

  3. American Diabetes Association. Hypoglycemia (low blood sugar).

  4. MedlinePlus. Low blood sugar - self-care.

  5. Centers for Disease Control and Prevention. Smoking and diabetes.

  6. Sharma A, Davis A, Shekhawat PS. Hypoglycemia in the preterm neonate: etiopathogenesis, diagnosis, management and long-term outcomes. Transl Pediatr. 2017;6(4):335-348. doi:110.21037/tp.2017.10.06

  7. American Diabetes Association. Prediabetes.

  8. Younk LM, Mikeladze M, Tate D, Davis SN. Exercise-related hypoglycemia in diabetes mellitus. Expert Rev Endocrinol Metab. 2011;6(1):93-108. doi:10.1586/eem.10.78

Additional Reading

By Craig Stoltz
Craig Stoltz is a Verywell Health guest author. He currently works in digital communications for the U.S. Department of Health and Human Services.