Type 1 Diabetes and Hypoglycemia: Causes and Treatments

Hypoglycemia, or low blood sugar, is a common complication of insulin therapy in type 1 diabetes. Most people taking insulin have experienced hypoglycemic episodes. Hypoglycemia can be dangerous, leading to seizures, coma, and death if left untreated, so it's important to be aware of the signs and know what to do if you experience low blood sugar.

This article will discuss hypoglycemia and its risks, symptoms, and management.

Woman checking blood sugar

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Risks of Hypoglycemia With Type 1 Diabetes

In type 1 diabetes, the pancreas does not produce insulin. Insulin is a hormone that signals cells to take up sugar from the blood, thus lowering blood sugar. People with type 1 diabetes must take insulin to keep blood sugar in a healthy range.

Hypoglycemia is a common side effect of insulin therapy. People with type 1 diabetes, on average, have about two episodes of mild hypoglycemia symptoms per week. Hypoglycemia can happen regardless of your overall blood sugar control, as measured by hemoglobin A1c level. However, those with a lower target hemoglobin A1c are at a higher risk of hypoglycemic episodes.

Symptoms of Hypoglycemia

Hypoglycemia can be categorized as mild, moderate, or severe, based on how low the blood sugar is. Symptoms become more serious the lower the blood sugar becomes.

Symptoms of Hypoglycemia by Blood Sugar Level
Category  Blood Sugar Level   Symptoms
 Mild  Less than 70 milligrams per deciliter (mg/dL) Anxiety, hunger, shakiness, sweating, cold or clammy skin, increased heart rate
 Moderate  Less than 55 mg/dL Irritability, dizziness, drowsiness, weakness, confusion, speech difficulty
Severe Less than 40 mg/dL Seizures, loss of consciousness, coma

Preparedness and Prevention

Being aware of what can lower blood sugar and cause hypoglycemic episodes is an important way to prevent these episodes from happening in the first place. The following can increase the risk of hypoglycemia:

  • Exercise
  • Taking too much insulin or taking insulin without eating enough food
  • Taking insulin too soon before eating
  • Not eating enough carbohydrates
  • Drinking alcohol
  • Hormonal changes, such as during menstruation and puberty
  • Being at high altitude

If you take insulin, it's important to check your blood sugar frequently. Discuss with your healthcare provider a plan for how often and at what times to check your blood sugar. Tell your healthcare provider about any changes to your diet, exercise regimen, or health, including any illnesses you're experiencing, so your insulin dose can be appropriately adjusted.

Despite being careful about your blood sugar, it's always a good idea to be prepared if low blood sugar happens to you. If you have diabetes, it's also important to let your family, friends, and coworkers know what to do in the event of an emergency.

Hypoglycemia Unawareness

Some people do not notice any symptoms when their blood sugar is low. This is known as hypoglycemia unawareness, and can happen to people who have had diabetes for a long time, who have had many episodes of hypoglycemia, or who take certain medications like beta-blockers. People with hypoglycemia unawareness need to be extra cautious and frequently check blood sugar.

Treatment of Hypoglycemia

If you experience signs and symptoms of hypoglycemia, or if your measured blood sugar is low, don't wait to get treatment. Blood sugar drops can become more severe with time. People who take insulin should be familiar with the 15-15 rule and have quick access to simple sugars that can raise their blood sugar.

The 15-15 Rule

For mild to moderate hypoglycemia, eat 15 grams of carbohydrates in the form of simple sugar, like candy or juice. Then wait and check your blood sugar 15 minutes later. If blood sugar remains lower than 70 mg/dL, eat 15 more grams and check again 15 minutes later. Always follow this by eating a balanced meal or snack so your blood sugar doesn't drop again.

Severe hypoglycemia is marked by symptoms like seizures and loss of consciousness, so you won't be able to treat the dangerously low blood sugar by eating sugar. Instead, an injection of a hormone called glucagon will be necessary to raise blood sugar.

People with diabetes may consider wearing a medical ID bracelet to alert bystanders of their diabetes in case serious complications occur.

Complications of Hypoglycemia

Hypoglycemia can be dangerous and result in the following:

  • Falls
  • Loss of consciousness
  • Seizure
  • Coma
  • Death

For this reason, it's important to be aware of early symptoms of low blood sugar that you can treat to prevent these complications.

When to Get Emergency Help

If your blood sugar is in the severe range, it's time to get immediate emergency assistance. In cases severe hypoglycemia, wearing a medical ID can be lifesaving. This can be a necklace or bracelet that lets bystanders and first responders know that you have diabetes and are on insulin, so you can receive appropriate treatment promptly.

Mild to moderate hypoglycemic episodes that resolve with treatment are not necessarily a reason to seek emergency medical care, however you should talk to your healthcare provider if you have frequent hypoglycemic episodes, since an adjustment to your insulin dose may be needed.


Hypoglycemic episodes are common in type 1 diabetes and can cause severe complications. Being aware of early symptoms of low blood sugar and using the 15-15 rule can prevent blood sugar from dropping to dangerous levels.

A Word From Verywell

It can be a challenge to keep blood sugar levels in a healthy range with type 1 diabetes. Your healthcare team can help get you on a regimen that works for you. Make sure to communicate any changes in your diet, exercise regimen, or health, such as an acute illness or upcoming surgery, with your diabetes provider so that your insulin dose can be adjusted to prevent hypoglycemia.

Frequently Asked Questions

  • Does drinking alcohol cause hypoglycemia if you have type 1 diabetes?

    Yes, alcohol can lead to hypoglycemia in diabetes, particularly if you have not eaten a meal before or while drinking alcohol. Your liver releases glucose, or sugar, into the blood to keep blood sugar levels in an appropriate range. However, when you drink alcohol, the liver has to metabolize alcohol and can fail to appropriately regulate blood sugar. People who take insulin are at higher risk of hypoglycemia from alcohol. In addition, drinking alcohol can lead to hypoglycemia unawareness.

  • Should I take insulin if my blood sugar is low?

    Do not take insulin if your blood sugar is low and you have symptoms since this can lead to a dangerous drop in your blood sugar. However, if your blood sugar is on the mildly low side, you do not have symptoms, and it is time for your scheduled insulin dose, the answer is more complicated. It will depend on whether your blood sugar is rising or falling, the last time you took insulin, the time of day, and your meal routine. This should be discussed with your diabetes care provider.

6 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.
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  2. American Diabetes Association. Blood sugar and insulin at work.

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

  4. Endocrine Society. Know hypo: Stay safe from severe hypoglycemia.

  5. Centers for Disease Control and Prevention. Low blood sugar (hypoglycemia).

  6. American Diabetes Association. Alcohol and diabetes.

By Angela Ryan Lee, MD
Angela Ryan Lee, MD, is board-certified in cardiovascular diseases and internal medicine. She is a fellow of the American College of Cardiology and holds board certifications from the American Society of Nuclear Cardiology and the National Board of Echocardiography. She completed undergraduate studies at the University of Virginia with a B.S. in Biology, medical school at Jefferson Medical College, and internal medicine residency and cardiovascular diseases fellowship at the George Washington University Hospital. Her professional interests include preventive cardiology, medical journalism, and health policy.