For people with diabetes, low blood sugar (hypoglycemia) occurs when there’s too much insulin and not enough sugar (glucose) in the blood. Hypoglycemia is defined as blood sugar below 70 milligrams per deciliter (mg/dL), or 3.9 millimoles per liter (mmol/L).
Several factors can cause hypoglycemia in people with diabetes, including taking too much insulin or other diabetes medications, skipping a meal, or exercising harder than usual.
Pay attention to early warning signs, so you can treat low blood sugar promptly. Treatment involves short-term solutions — such as taking glucose tablets — to raise your blood sugar into a normal range.
Untreated, diabetic hypoglycemia can lead to seizures and loss of consciousness — a medical emergency. Rarely, it can be deadly. Tell family and friends what symptoms to look for and what to do in case you’re not able to treat the condition yourself.
Hypoglycemia is most common among people who take insulin, but it can also occur if you’re taking certain oral diabetes medications.
Common causes of diabetic hypoglycemia include:
- Taking too much insulin or diabetes medication
- Not eating enough
- Postponing or skipping a meal or snack
- Increasing exercise or physical activity without eating more or adjusting your medications
- Drinking alcohol
- Blood sugar regulation
The hormone insulin lowers glucose levels when glucose is elevated. If you have type 1 or type 2 diabetes and need insulin to control your blood sugar, taking more insulin than you need can cause your blood sugar level to drop too low and result in hypoglycemia.
Hypoglycemia also may result if, after taking your diabetes medication, you eat less than usual or exercise more than you normally do. Your doctor can work with you to prevent this imbalance by finding the dose that fits your regular eating and activity patterns.
Early signs and symptoms of diabetic hypoglycemia include:
- Irritability or moodiness
- Anxiety or nervousness
Diabetic hypoglycemia can also occur while you sleep. Signs and symptoms, which can awaken you, include:
- Damp sheets or bedclothes due to perspiration
- Tiredness, irritability or confusion upon waking
If diabetic hypoglycemia goes untreated, signs and symptoms of severe hypoglycemia can occur. These include:
- Clumsiness or jerky movements
- Muscle weakness
- Difficulty speaking or slurred speech
- Blurry or double vision
- Convulsions or seizures
Take your symptoms seriously. Diabetic hypoglycemia can increase the risk of serious — even deadly — accidents. Identifying and correcting the factors contributing to hypoglycemia, such as medications you take or irregular mealtimes, can prevent serious complications.
Informing people you trust, such as family, friends and co-workers, about hypoglycemia is important. Their knowing what symptoms to look for and what to do in case you’re not able to help yourself can make a potentially difficult situation easier to manage. It’s also important that they know how to give you a glucagon injection, in case it becomes necessary.
Symptoms can differ from person to person or from time to time, so it’s important to monitor your blood sugar levels regularly and keep track of how you’re feeling when your blood sugar is low. Some people don’t have or don’t recognize early symptoms (hypoglycemia unawareness). If you have hypoglycemia unawareness, you may require a higher glucose goal range.
When to see a doctor
Hypoglycemia can leave you confused or even unconscious, which requires emergency care. Make sure your family, friends and co-workers know what to do.
If you lose consciousness or can’t swallow:
- You shouldn’t be given fluids or food, which could cause choking
- You need an injection of glucagon — a hormone that stimulates the release of sugar into the blood
- You need emergency treatment in a hospital if a glucagon injection isn’t on hand
- If you have symptoms of hypoglycemia several times a week, see your doctor. You may need to change your medication or your dosage or otherwise adjust your diabetes treatment program.