Low blood sugar can be a life-threatening situation if not treated right away. Knowing how to recognize the signs of hypoglycemia is very important.

Hypoglycemia is a dangerous condition that occurs when the amount of glucose in the blood drops too low, causing dizziness, shakiness, lightheadedness, and a rapid heartbeat. Glucose is a sugar that the body needs for energy. After eating, glucose is absorbed and extra amounts are stored in the muscles and liver. This stored glucose can be released when needed as a backup energy source.

Hypoglycemia is defined as blood glucose levels below 70 milligrams per deciliter (mg/dL). To determine your blood sugar level, you must test your blood.

People with diabetes are familiar with checking glucose levels to ensure they are not too high (hyperglycemia) or too low (hypoglycemia). Hypoglycemia is more common in people with type 1 diabetes, but people with type 2 can experience it as well. Those using insulin and certain diabetes medications must be cautious about low blood sugar.

Although low blood sugar is less common in people without diabetes, it can still happen. Diet, exercise, and even weather changes can affect blood glucose.

Risk increases if you are over 65, have had hypoglycemia before, or have conditions such as kidney disease, heart disease, or cognitive impairment.

Below are the main signs and symptoms of hypoglycemia.

Fast Heartbeat

Why it happens
When blood glucose drops, the body activates a crisis response. The adrenal glands release norepinephrine, which makes the heart beat faster. This helps pump more blood to the brain and vital organs so that cells can access more glucose.

Shaking And Jitteriness

Why it happens
Norepinephrine also works as a neurotransmitter, sending signals in the nervous system. This can make you feel shaky and jittery.

Nervousness And Anxiety

Why it happens
The same hormone, norepinephrine, is responsible for feelings of nervousness and anxiety. If you suddenly feel anxious, it may be linked to low blood sugar.

Irritability And Confusion

Why it happens
The brain and nervous system need glucose for energy. Without enough, behavior may change. People may become confused, irritable, or unusually impatient. This is often described as being “hangry”—a mix of hungry and angry.

Dizziness

Why it happens
When glucose is too low, the brain lacks its energy source. This can make you feel lightheaded or dizzy, and in severe cases, cause fainting. Fainting is dangerous as it can lead to injuries.

Headache

Why it happens
The brain consumes a large share of glucose. When deprived, headaches can occur because brain cells cannot function properly.

Hunger

Why it happens
Hunger is a natural symptom of hypoglycemia. The body releases acetylcholine, a neurotransmitter that stimulates hunger signals. Eating carbohydrates usually helps restore blood glucose. People with diabetes often follow the “15-15 rule”—eating 15 grams of carbs and rechecking glucose after 15 minutes.

Tiredness

Why it happens
Without enough glucose, the nervous system slows down, leaving you feeling weak and fatigued.

Difficulty Speaking

Why it happens
Speech centers in the brain need glucose. Low sugar can cause slurred or difficult speech. Be cautious, as difficulty speaking may also be a sign of stroke.

Sweating

Why it happens
Low glucose also causes sweating, triggered by acetylcholine release. Sweating may happen during the day or at night, sometimes soaking pajamas or sheets.

Poor Sleep Quality

Signs at night
Blood sugar can drop overnight and remain low for hours. This may cause:

  • Crying out or shouting during sleep

  • Nightmares

  • Waking up sweaty with damp clothes or sheets

  • Morning tiredness, irritability, or confusion

Severe Symptoms

If blood glucose falls below 54 mg/dL, the brain becomes severely deprived of energy. This can cause:

  • Trouble walking

  • Blurred vision

  • Loss of consciousness

  • Seizures

  • In extreme cases, death

When To See A Healthcare Provider

Symptoms of hypoglycemia must be treated immediately. People with diabetes should always carry quick sources of glucose such as fruit juice, glucose tablets, or hard candy. If these do not stabilize blood sugar, glucagon may be prescribed as an emergency treatment.

If you experience frequent low blood sugar, consult a healthcare provider to adjust your treatment plan.

A Quick Review

Hypoglycemia is a serious condition that requires immediate attention. If not recognized and treated, it can be life-threatening.

Some people develop hypoglycemia unawareness, meaning they do not notice early symptoms. For this reason, regular blood glucose checks are essential, especially before driving or performing risky activities.

If low blood sugar is happening often, see a healthcare provider to prevent severe complications and ensure proper management.