Hypoglycemia, or low blood sugar, is a condition that can affect anyone, not just people with diabetes. It happens when your blood glucose drops below normal levels, leading to symptoms like shakiness, confusion, or even fainting. Understanding what causes hypoglycemia, recognizing the signs, and knowing what to do when it happens can help you stay safe and feel more in control.

What is Hypoglycemia?

Hypoglycemia, also known as low blood sugar or low blood glucose, is a condition in which your blood sugar level is lower than the normal range.

If you have a fasting blood glucose test, a level under 100 mg/dL (5.5 mmol/L) is considered normal.
If you have a random blood glucose test, a level under 125 mg/dL (6.9 mmol/L) is considered normal.

Low blood glucose (hypoglycemia) is a blood glucose level below 70 mg/dL or 3.9 mmol/L. However, for some people who are young and lean, a fasting blood glucose level below 70 mg/dL may be normal. Patients with a history of uncontrolled diabetes may begin to experience symptoms of hypoglycemia above 70 mg/dL, given that their bodies are not used to experiencing normal blood sugars as much.

Insulin and Glucagon

When you eat carbohydrates, they are digested into sugar and absorbed into the blood, raising your blood sugar level. In response, the pancreas releases the insulin hormone that prompts the body’s cells to take up glucose from the blood and store it for energy, lowering blood sugar levels. Conversely, when the blood glucose level drops, the pancreas releases a hormone called glucagon, which triggers the release of stored glucose and gluconeogenesis (glucose production) in the liver, thereby raising the blood sugar level.

When the blood glucose level drops, the pancreas releases a hormone called glucagon, which triggers the release of stored glucose and gluconeogenesis (glucose production) in the liver.

Insulin and glucagon control blood sugar levels and keep them in the normal range in healthy individuals.

Recognizing Low Blood Sugar Symptoms

Early symptoms of hypoglycemia include:

Hunger pangs
Sweating
Flushed face
Fast or irregular heartbeat
Anxiety or nervousness

Other signs and symptoms of hypoglycemia may include:

Pale skin or clammy skin
Chills
Fatigue, weakness, low energy
Headache
Dizziness or lightheadedness
Shakiness or trembling
Nausea
Irritability or crankiness
Impatience
Aggression
Difficulty concentrating
Tingling sensations in the lips, tongue, or cheeks
Blurred vision or double vision
Clumsiness
Nightmares

Seek immediate medical help if you experience serious signs and symptoms of hypoglycemia (very low blood glucose levels), including:

Confusion
Difficulty speaking
Difficulty with coordination
Seizures
Coma

What Happens If Blood Sugar Gets Too Low While Sleeping?

It is called nocturnal hypoglycemia if blood glucose levels fall below 70 mg/dL while sleeping. Research suggests that up to half of all hypoglycemia episodes occur during sleep, particularly in people taking insulin or sulfonylureas (e.g., glipizide, glyburide).

Risk factors include skipping meals, exercising before bedtime, and drinking alcohol before going to bed. In addition, infections can cause low blood glucose at night.

Your family members, housemates, or roommates should know how to recognize nighttime hypoglycemia and use a glucagon kit to treat low blood glucose.

Causes of Low Blood Sugar Without Diabetes

People who don’t have diabetes mellitus can experience low blood sugar (hypoglycemia) due to the following causes:

Drinking alcohol, especially heavy alcohol consumption, on an empty stomach. Too much alcohol can prevent the liver from releasing stored glucose, leading to hypoglycemia.
A rare tumor in the pancreas called an insulinoma, which produces too much insulin.
Hormonal disorders include a lack of cortisol, growth hormone, or thyroid hormone.
Sepsis (a severe, widespread infection affecting the whole body).
Critical illnesses such as advanced heart failure, cirrhosis, severe hepatitis, liver failure, chronic kidney disease, or kidney failure.
Certain types of weight-loss surgery and other surgeries (hypoglycemia after eating can develop several years after the surgical procedure – this is called reactive hypoglycemia or postprandial hypoglycemia).
Certain antibiotics, medicines for heart disease, and antimalarials such as quinine.
Accidental ingestion of diabetes medications.
Malnutrition or prolonged starvation.
Eating disorders, such as anorexia nervosa.

Physical Activity

Intense exercise can cause blood sugar to drop quickly. During physical activity, your muscles contract, and your cells take up glucose from blood for energy.

Exercise also increases insulin sensitivity, lowering blood sugar levels for up to 24 hours after a workout.

Dehydration can also cause low blood sugar. Staying hydrated is important, as well as drinking enough water before, during, and after exercising.

Carbohydrates

When you eat food containing carbohydrates, your digestive system breaks them down into sugar, which enters your bloodstream and raises your blood sugar level.

The glycemic index ranks carbohydrates according to how quickly and by how much they raise blood sugar levels. High-glycemic index foods like white bread are digested very quickly and cause a spike in blood sugar levels. Low-glycemic index foods like whole oats are digested more slowly, leading to a more gradual increase in blood glucose levels.

Consuming balanced meals that include protein, fiber, and healthy fats can help reduce blood sugar fluctuations.

Immediate Treatment for Low Blood Sugar

How to Raise Blood Sugar Quickly

The American Diabetes Association (ADA) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommend using the 15/15 rule to raise blood sugar quickly and treat low blood glucose.

This means you should eat 15 grams of fast-acting carbohydrates, wait 15 minutes, and recheck your blood sugar. Repeat as needed until the blood sugar level is above 70 mg/dL.

Note: Children may need 10 grams, and infants may need 8 grams of fast-acting carbs to treat hypoglycemia. Talk to your child’s doctor about the appropriate amount.

Remember that mild or moderate hypoglycemia should be treated as soon as possible to avoid the progression to severe low blood sugar. Severe hypoglycemia is a medical emergency, and you may need help from others if you develop symptoms such as confusion, difficulty speaking, or seizures, or if you lose consciousness.

What to Eat When Your Blood Sugar Is Low?

You should eat fast-acting carbs if you have symptoms of low blood sugar. These foods raise blood glucose levels quickly and work fast to treat low blood sugar. Examples include:

1 tablespoon of sugar, honey, or corn syrup (do not give honey to children younger than 1 year old).
1/2 cup (4 ounces) of fruit juice or regular soda (not diet soda).
Jellybeans or hard candies (use the information on the nutrition label to find out how many to eat for 15 grams of carbs).

Glucose Tablets, Gel, and Injections

For hypoglycemia treatment, you can purchase glucose tablets, gels, or injections. These products are typically stocked in pharmacies' diabetes care sections.

Glucose tablets are small, chewable tablets that contain 4-5 grams of fast-acting carbs per tablet. Glucose tabs come in many flavors.
Glucose gel tubes contain a flavored gel that can be directly squeezed into your mouth. Each packet contains about 15 grams of fast-acting carbohydrates.
Glucagon emergency kit is an injection administered under the skin for people with diabetes who develop severe hypoglycemia. You should seek emergency medical care after using it. An intramuscular glucagon kit is also available.
Glucagon nasal spray (brand name Baqsimi) is a dry nasal spray with 3 mg of glucagon nasal powder in each dose. It treats very low blood sugar in adults and children 4 years of age and older.

Managing Hypoglycemia Long Term

Monitoring Blood Sugar Levels

People with diabetes mellitus take diabetes medicines such as insulin or diabetes pills to treat diabetes. These medications aim to keep blood glucose levels in the target range. However, hypoglycemia can occur as a side effect of diabetes medicines. This is more likely if diabetic patients eat less than usual or exercise more than usual while taking the regular doses of their diabetes medicines. That’s why regularly monitoring blood sugar levels is vital for people with diabetes. If you are being treated for diabetes, your doctor will recommend using a home blood glucose meter as part of your diabetes management plan.

Note: An insulin pump and continuous glucose monitor (CGM) system can check glucose levels in real time and adjust your insulin dose based on the level. CGMs like Dexcom and Freestyle Libre can alert patients to low glucose levels before symptoms develop.

Hypoglycemia Unawareness

People who experience repeated episodes of hypoglycemia can develop hypoglycemia unawareness. This means their body and brain stop producing hypoglycemia symptoms and warning signs such as trembling and palpitations.

If you have had hypoglycemia diagnosed many times, you are at risk of hypoglycemia unawareness. In this case, your health care provider may change your diabetes medicines, raise the target range of blood sugar goals, and/or recommend hypoglycemia awareness training.

Note: A continuous glucose monitor (CGM) measures blood glucose levels in real time and can alert you when your blood sugar is too low.

When to Consult a Healthcare Provider

Consult your health care provider if you have recurrent episodes of hypoglycemia. Severe hypoglycemia can be life-threatening. Fear of hypoglycemia can lead to undertreatment of diabetes and cause health complications as well.