Medically reviewed by Carina Fung, PharmD, BCPPS

What is hypoglycemia?

Hypoglycemia1 occurs when the body’s blood glucose (sugar) stores are too low.

Glucose, which comes from the food you eat, provides energy to the body’s cells and tissues. While glucose is absorbed by the blood after a meal, if you consume more glucose than you need, your body stores the excess in your muscles and liver.

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When blood glucose levels fall below normal, your body releases a hormone signal that instructs your liver to release more glucose. If your body is unable to raise its own blood glucose levels through this method, you are considered to have hypoglycemia.

Hypoglycemia can be extremely dangerous if your blood sugar falls too low. While hypoglycemia is a common side effect of certain diabetes medications, a person can have hypoglycemia without having diabetes.

Hypoglycemia vs. hyperglycemia

These two conditions can be thought of as opposites: hypoglycemia refers to low blood sugar (glucose), while hyperglycemia is characterized by high blood sugar. Hyperglycemia2 typically occurs in individuals with uncontrolled diabetes, while hypoglycemia can occur in people with or without diabetes.

While some fluctuations in blood sugar are normal, a healthy individual should have a blood glucose range of 60–140 mg/dL. Anything higher than this is considered hyperglycemia, while a number lower than this indicates hypoglycemia.

The symptoms of hyperglycemia differ from those of hypoglycemia. Two of the hallmark symptoms of high blood sugar are extreme thirst and unintentional weight loss. The most common symptoms of hypoglycemia are feeling faint, having a racing pulse, and experiencing cold sweats.

How common is hypoglycemia?

In individuals with type 1 diabetes, the incidence3 of severe hypoglycemia ranges from .038 to 3.2 episodes per year. In those with type 2 diabetes, the incidence of severe hypoglycemia ranges from .0004 to .96 episodes per year.

Ultimately, however, it’s challenging to measure the incidence of moderate hypoglycemic episodes, as many do not require medical intervention or reporting.

Hypoglycemia causes

People with type 1 diabetes do not make adequate amounts of insulin, while people with type 2 diabetes are resistant to the effects of insulin. Without enough insulin in the body, glucose may begin to accumulate in the bloodstream. If left untreated, this can become very dangerous.

People with diabetes can inject insulin or take oral medications to combat rising glucose levels. However, an overcompensation for high blood sugar with diabetes medication can cause blood sugar levels to overcorrect and fall dangerously low, which leads to hypoglycemia.

However, low blood sugar can affect people with or without diabetes. There are several reasons why a person without diabetes may have low blood sugar. These potential causes include4:

  • Alcohol: Drinking in excess without giving yourself adequate nutrition can cause low blood sugar by preventing your liver from releasing glucose into your bloodstream.
  • Hormone deficiencies: Adrenal or pituitary gland tumors can block the production of specific hormones, impacting glucose production. In particular, children without adequate growth hormone can experience hypoglycemia.
  • Too much insulin: The body may produce excess insulin in response to a pancreatic tumor or the engorgement of pancreatic cells.
  • Certain illnesses: Illnesses that affect the liver, such as hepatitis and cirrhosis, can cause low blood sugar. Kidney illnesses can also cause a buildup of glucose by preventing the body from properly filtering and excreting medications and other wastes.
  • Medications: Some medications, such as the malaria drug quinine (generic Qualaquin), can cause hypoglycemia in children and people with kidney problems. Taking another person’s oral diabetes medication if you do not have diabetes can also cause low blood sugar.

Diabetic hypoglycemia

Hypoglycemia happens in people with diabetes as the result of one of the following5:

  • The person does not eat enough food.
  • The person exercises intensely without eating a snack or decreasing their insulin dose beforehand.
  • The person waits too long to eat between meals.
  • The person drinks alcohol in excess.
  • The person injects too much insulin.

Risk factors for hypoglycemia

Hypoglycemia can occur in both those who have diabetes and those who do not. General risk factors for hypoglycemia in both groups include6:

  • Older age: People over the age of 60 are nearly twice as likely to have a severe episode of hypoglycemia than those younger than 60.
  • Having diabetes: Individuals with diabetes who skip meals can disturb their blood glucose levels and cause them to fall too low. Additionally, taking diabetes medications without accompanying food can lead to a hypoglycemic episode in some cases.
  • Taking certain medications: One of the first symptoms of hypoglycemia is a high, irregular heart rate. If you take medications that mask these symptoms, such as a beta-blocker, you may put yourself at risk for a severe hypoglycemic episode, as you will not be able to recognize the early signs of low blood sugar. Individuals who take tricyclic antidepressants7 (versus SSRIs) are also at a greater risk of having severe hypoglycemic episodes.
  • Kidney dysfunction: The kidneys help to process and metabolize insulin by reabsorbing glucose and excreting waste products. For this reason, individuals with kidney problems may be at a higher risk of hypoglycemia.
  • Cognitive problems: As hypoglycemia is associated with older age, many hypoglycemic individuals also have cognitive dysfunctions, such as Alzheimer’s disease or dementia. Individuals with cognitive difficulties may be at a higher risk of severe hypoglycemic episodes because they may forget to take (or take the incorrect dose of) their medication or have difficulty sticking to a consistent eating schedule.
  • Being unaware of your condition: Individuals who have hypoglycemia or have had a severe episode of hypoglycemia in the past often know how to recognize the warning signs that an episode is imminent. Hypoglycemia unawareness can increase your risk of developing severe hypoglycemia, as you are not as likely to recognize the early warning signs or symptoms.

Hypoglycemia symptoms

Early symptoms of hypoglycemia can include8:

  • Tachycardia (fast or irregular heartbeat)
  • Clammy hands
  • Shakiness
  • Fatigue or tiredness
  • Sweating more than usual
  • Difficulty speaking
  • Feeling anxious
  • Hunger
  • Irritability
  • Lip, tongue, or cheek numbness

When hypoglycemia progresses past the initial symptoms, it can cause the following:

  • Seizures
  • Confusion or disorientation
  • Blurry vision
  • Loss of consciousness or fainting

If you experience any of the signs and symptoms of hypoglycemia, seek prompt medical treatment. Untreated hypoglycemia can pose serious health risks and even become life-threatening.

Complications from hypoglycemia

If left untreated, hypoglycemia can be extremely dangerous9 and cause a number of health complications, including seizures, fainting, or even death. Additionally, low blood sugar is known to be associated with dizziness and loss of consciousness, which can lead to potential falls, car accidents, or other injuries.

Disclaimer: The information on this site is generalized and is not medical advice. It is intended to supplement, not substitute for, the expertise and judgment of your healthcare professional. Always seek the advice of your healthcare professional with any questions you may have regarding a medical condition. Never disregard seeking advice or delay in seeking treatment because of something you have read on our site. RxSaver makes no warranty as to the accuracy, reliability or completeness of this information.

If you are in crisis or you think you may have a medical emergency, call your doctor or 911 immediately.