Low blood sugar in the mornings, also known as morning hypoglycemia, can make people feel faint, light-headed, or confused when they wake up.

Having low blood sugar in the mornings is common in people on medication for diabetes, though it can also happen for other reasons.

In this article, we look at the reasons why blood sugar can drop in the morning, symptoms of hypoglycemia, and how to treat and prevent this from happening.

What causes low blood sugar in the morning?

When people go for long periods without eating, the levels of sugar in the blood drops. Since most people do not wake up to eat, blood sugar levels can fall overnight.

Following a period without food, blood sugar levels are known as fasting blood sugar.

Usually, an overnight fast will not affect blood sugar levels, because the body will prevent it from dropping to dangerous levels; for example, the liver releases some of its stored sugar overnight.

Normal fasting blood sugar levels for a person with diabetes are between 70 and 130 milligrams per deciliter (mg/dL). A person with diabetes can measure their fasting blood sugar levels in the morning before breakfast.

When blood sugar levels fall below 70 mg/dL, people may experience symptoms of low blood sugar. Some people may feel very sick with blood sugar levels of 70 mg/dL, while others might not notice signs until blood sugar dips lower than this.

A person who has frequent episodes of hypoglycemia will become gradually less aware of these symptoms. Conversely, a person who typically has high blood sugar levels can develop symptoms even at levels that are otherwise considered normal.

A person who is pregnant is more likely to experience morning hypoglycemia because their body uses more calories to help nurture the developing fetus.

Some other causes of low blood sugar in the morning include:

• diabetes medications, especially long-acting diabetes medications of the sulfonylurea family or insulin
• some other drugs, such as the pneumonia drug pentamidine
• alcohol consumption, particularly in people with type 1 diabetes
• organ failure, mainly due to chronic kidney disease
• recent stomach surgery, particularly bariatric (weight loss) surgery
• rare enzyme or hormone disorders that make it difficult for the body to absorb or break down glucose
• a sudden increase in activity level, particularly in people with diabetes, since exercise can lower blood glucose
• vomiting or diarrhea
• low-carbohydrate diets
• an insulin-producing tumor (insulinoma)
• other hormonal imbalances, such as low adrenal function and low growth hormone
• accidental ingestion of antidiabetic drugs

In rare cases, low blood sugar may be due to cancer, particularly tumors that release insulin-like factors or use up large amounts of glucose.

Symptoms of hypoglycemia

Symptoms of hypoglycemia range from mild to more severe. Initially, a person will experience symptoms, such as a fast heartbeat, sweating, hand tremors, and hunger.

However, if the blood sugar levels keep dropping, a person may begin to experience headaches, confusion, changes in personality, irritability, seizures, and even coma if not treated.

Common symptoms include:

• feeling jittery, shaky, or sweaty
• loss of coordination
• anxiety
• irritability
• exhaustion
• a headache
• fatigue
• lightheadedness
• difficulty concentrating
• a fast heartbeat
• paleness
• changes in personality
• hunger, including physical symptoms of hunger, such as nausea or a stomach ache
• muscle aches
• blurred vision

If hypoglycemia is left untreated, symptoms can get worse. This is most common in people who use insulin to control their diabetes and experience frequent episodes of low blood sugar, which might make them less aware of the early warning symptoms.

Symptoms of severe low blood sugar include:

• fainting and loss of consciousness
• seizures

Anyone experiencing severe low sugar levels should see a doctor immediately as it is a medical emergency. People who are in organ failure or who have another serious medical condition, including diabetes, should go to the emergency room.

Treatment

Treatment for hypoglycemia depends on its cause. When hunger is the culprit, eating a glucose-rich meal, such as fruit and pancakes, can quickly raise blood glucose levels.

Consuming rapid-acting carbohydrates, such as 8 ounces of fruit juice, regular coke, glucose tablets, or candy is also a good way to treat low sugar levels.

People with diabetes who often experience low blood sugar levels in the morning may need to alter their medication dosage or change their diet. However, always discuss symptoms with a doctor before making any changes to diet or medication.

People who develop hypoglycemia because of alcohol may need to avoid alcohol. Alcohol use disorder (AUD) is a dangerous medical condition and withdrawal can be difficult.

People who drink too much alcohol should talk to a doctor about their treatment options. A person with AUD along with diabetes or another serious medical condition may need a medically supervised detox.

When hypoglycemia is due to a temporary illness, such as a stomach virus, drinking plenty of water or drinking an electrolyte drink can help prevent dehydration. If vomiting or diarrhea continues for more than a few days, see a doctor.

Other causes of morning hypoglycemia can be dangerous or even life-threatening. So, people who frequently experience low blood sugar in the morning should see a doctor.

Keeping a log of symptoms can help with getting an accurate diagnosis. It may also help a person work out what causes low blood sugar levels in the morning and how to prevent it happening.

Prevention

It may not be possible to prevent morning low blood sugar when symptoms are due to a serious medical condition, which is why it is essential to address the underlying condition.

However, remaining well-nourished and eating regular meals may prevent symptoms from getting worse.

When caused by a lack of eating, a person can prevent symptoms by:

• avoiding low carbohydrate diets, which can cause low blood glucose
• eating a snack before bed
• choosing high-fiber snacks, as fiber-rich food slows down glucose absorption and can help prevent low blood sugar in the morning
• eating small, frequent meals throughout the day rather than three larger meals

People with diabetes should monitor their blood glucose levels throughout the day. They may notice a pattern that can help them prevent blood sugar drops.

Changing diabetes medications, or in some cases, stopping them, can help, but always see a doctor before making any medication changes.

Outlook

Low blood sugar in the mornings happens for many different reasons. It is vital not to self-diagnose. Even if symptoms go away after eating a meal, consider making permanent lifestyle changes to reduce the risk of morning blood sugar drops.

Healthful changes include eating a later dinner or having a snack before bed. See a doctor for help managing chronically low morning blood sugar.

Extremely low blood sugar prevents the body from getting the energy it needs and is a medical emergency. So, if eating a meal does not relieve symptoms, a person should go to the emergency room or call a trusted doctor.

Most people who experience low blood sugar in the morning can manage symptoms with a few simple lifestyle changes. Though low blood sugar can make a person feel very ill, it is not always a cause for concern.

When blood sugar levels are dangerously low, prompt treatment will increase the chances of a full recovery.

—Zawn Villines