Hypoglycemia refers to low levels of sugar, or glucose, in the blood. Low blood sugar can cause tiredness, shaking, and many other symptoms. It can be life threatening in severe cases.
All cells within the body, including in the brain, need energy to function. Glucose supplies energy, and the hormone insulin enables the cells to absorb and use it.
In severe cases, low blood sugar, or glucose, may lead to coma and death.
Hypoglycemia can occur with several conditions, but it
This article explains hypoglycemia, including its symptoms and treatment options.
Hypoglycemia happens when there is not enough glucose, or sugar, in the blood.
The National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK) notes that symptoms usually appear when blood sugar levels are below
People with low blood sugar may want to use a blood glucose meter — a small, portable machine that monitors blood sugar levels. Some monitors sound an alarm if levels drop below a certain level. People can purchase blood glucose monitors online or discuss with their healthcare team.
Learn about home blood glucose monitors and how to use them here.
People with mild hypoglycemia may experience the following common symptoms:
- hunger
- tiredness
- tremor or shaking
- sweating
- heart palpitations
- rapid or irregular heart rate
- dizziness and weakness
- nausea
Severe hypoglycemia may involve:
- confusion
- seizures
- nightmares
- fainting
- coma
Complications
If a person does not take action, they may have:
- difficulty eating or drinking
- seizures
- a loss of consciousness
- coma
Severe hypoglycemia can be life threatening, and in rare cases, may lead to death without treatment.
Someone who regularly experiences hypoglycemia may be unaware that it is happening or getting worse. They may not notice the warning signs, which may lead to severe and possibly fatal complications.
People may experience hypoglycemia for reasons including:
- Not eating enough: Fasting or missing a meal may lead to low blood sugar levels. Not eating enough carbohydrates can also cause blood sugar levels to fall.
- Increased activity: Increasing physical activity levels can lower blood sugar levels for some time, especially in those with type 1 diabetes.
- Some medications: Quinine, a drug that prevents malaria, can trigger hypoglycemia. High doses of salicylates, used to treat rheumatic disease, or propranolol for high blood pressure, may also cause blood sugar levels to drop. It can also happen when a person takes diabetes medication without having diabetes.
- Alcohol consumption: Drinking large amounts of alcohol can cause the liver to stop releasing stored glucose into the bloodstream.
- Some liver diseases: Drug-induced hepatitis can lead to hypoglycemia because it affects the liver.
- Kidney disorders: People with a kidney disorder may have problems excreting medications. This can result in low blood sugar levels.
- Insulinoma: A tumor in the pancreas can cause the pancreas to produce too much insulin.
- Endocrine problems: Some adrenal and pituitary gland disorders can lead to hypoglycemia. This is more common in children than adults.
- Reactive, or postprandial, hypoglycemia: The pancreas produces too much insulin after a meal.
- Tumors: Rarely, a tumor in a part of the body other than the pancreas can cause hypoglycemia.
- Severe illness: Some diseases, such as cancer, can affect many organs, including the pancreas. This can lead to hypoglycemia.
Blood sugar regulation
The digestive system breaks down carbohydrates from food. One of the molecules this creates is glucose, the body’s main energy source.
Glucose enters the bloodstream after we eat. Insulin, a hormone the pancreas produces, then allows cells in the body to absorb glucose. This means that even if plenty of glucose is available in the bloodstream, cells will starve of energy without insulin.
After eating, the pancreas automatically releases the right amount of insulin to allow cells to absorb enough glucose from the bloodstream. As glucose enters the cells, blood sugar levels fall.
Any extra glucose goes into the liver and muscles in the form of glycogen, or stored glucose. The body can use this glucose later when it needs more energy.
Insulin is responsible for bringing high blood sugar levels back to normal.
If glucose levels fall because an individual has not eaten for a while, the pancreas secretes glucagon, another hormone, which triggers the breakdown of stored glycogen into glucose.
The body then releases the glycogen into the bloodstream, bringing glucose levels back up.
If people take insulin and inject too much, it can cause cells to absorb excess glucose from the bloodstream, leading to low blood sugar.
Hypoglycemia and diabetes
Both type 1 and type 2 diabetes involve a problem with insulin. The American Diabetes Association (ADA) classes low blood sugar as less than 70 mg/dl.
| Type | Definition |
|---|---|
| Type 1 diabetes | Damage to the cells that normally produce insulin means that the body cannot produce insulin. |
| Type 2 diabetes | The body’s cells do not respond properly to insulin, or the pancreas may not release enough insulin. |
In both types of diabetes, the cells do not get enough energy from glucose.
People with type 1 diabetes and some with type 2 diabetes need to take insulin or other medications to reduce their blood sugar levels.
If the insulin dose is too high, blood sugar levels can fall too far, leading to hypoglycemia.
Hypoglycemia can also occur if the person exercises more than usual or does not eat enough.
A person does not need to increase their dose to have too much insulin in their body. It may be that the insulin they took was more than their body needed at that moment.
According to the
Learn about insulin resistance here.
Hypoglycemia in children: Pediatric ketotic hypoglycemia
Some children experience pediatric ketotic hypoglycemia, a condition involving low blood sugar levels and high levels of ketones. If people do not have enough glucose to use as energy, the body begins to break down fat in the body instead. The body produces chemicals called ketones as a by-product of breaking down fat.
According to a
Pediatric ketotic hypoglycemia may affect children from 6 months old and often resolves after the age of 6 years.
Symptoms
Symptoms of hypoglycemia in infants and children may include:
- lethargy
- abnormal crying
- decreased feeding
- jittery
- irritability
- confusion
- drowsiness
- sweating
- pallor
- pounding heart
If a child shows any of the above signs or symptoms, a doctor should examine them as soon as possible.
Insulin autoimmune syndrome
Another possible cause of hypoglycemia is insulin autoimmune syndrome, a rare disease that happens when the body’s immune system attacks insulin, mistaking it for an unwanted substance.
Symptoms tend to appear suddenly, according to the Genetic and Rare Diseases Information Center (GARD). Symptoms often go away after a few months, but they can return if blood sugar levels drop.
Symptoms and treatment are similar to those for hypoglycemia due to other causes. Treatment can usually control the symptoms.
Anybody with symptoms of hypoglycemia and does not know the underlying cause will need to consult with a doctor. A doctor may:
- order a blood test to measure blood sugar levels
- ask about symptoms and whether they improve after blood sugar levels return to normal
- check the person’s medical history and any medications they are taking
- ask about alcohol consumption
Whipple’s triad
A collection of three criteria, known as Whipple’s criteria, can suggest that symptoms stem from a pancreatic tumor.
The three criteria of Whipple’s triad are
- signs and symptoms indicate hypoglycemia
- when symptoms occur, a blood test shows low plasma glucose levels are less than 55 mg/dl
- when glucose rises to normal levels, symptoms go away
During a doctor’s appointment, a person may not have symptoms. The doctor may ask them to fast for a time, usually overnight. This allows hypoglycemia to occur so that the doctor can make a diagnosis.
Some people may have to spend time in the hospital and fast for longer.
If symptoms appear after eating, they will need another glucose test after food.
If people have hypoglycemia or diabetes, they can discuss an eating plan with a healthcare provider. Tips may include the following:
- eating snacks and small meals around every three hours throughout the day
- opting for a variety of foods, including protein, high-fat foods, and high-fiber foods
- limiting foods high in sugar
Hypoglycemia and hyperglycemia both relate to blood sugar levels, but they are not the same.
| Type | Explanation |
|---|---|
| Hypoglycemia | There is too little glucose in the blood, |
| Hyperglycemia | Glucose levels are too high, |
Preventing hypoglycemia will depend on the underlying cause. Managing the underlying condition can help to avoid hypoglycemia. There are steps people can consider that
- Following a treatment plan: It is important to follow doctor’s instructions and seek help if symptoms change.
- Checking blood glucose levels: People at risk should check their blood sugar levels regularly and know how to recognize the symptoms.
- Following alcohol guidelines: Sticking to the daily alcohol limits that a doctor recommends and avoid drinking alcohol without food.
- Being aware of exercise: Eating a carbohydrate-rich snack before exercising and understanding how physical activity can impact blood sugar levels.
- Taking care when sick: Vomiting, for example, can prevent the body from absorbing enough energy.
- Being prepared: Carrying a container of sugary fruit juice or a candy bar in case symptoms appear.
- Telling people: Those prone to low blood sugar should inform friends, colleagues, and family members.
- Carrying medical ID: A form of ID or medical bracelet will enable healthcare providers, emergency services, and others to know what to do sooner.
Hypoglycemia can lead to symptoms such as dizziness, weakness, and, in severe cases, a loss of consciousness.
People with some medical conditions, including diabetes, may have a higher risk of hypoglycemia.
It is important for people to know how to recognize the symptoms and be ready to take action if they occur. Consuming carbohydrates or glucose when blood sugar levels drop can help return them to a normal range.