Symptoms
The symptoms of
hypoglycemia may vary from episode to episode because
low blood sugar can be mild, moderate, or severe. Increasingly severe symptoms
appear as the blood sugar level falls.
In healthy people,
fasting blood sugar levels are usually between 70 and 99
mg/dL.
Mild
hypoglycemia
Symptoms of mild low blood sugar usually
develop when blood sugar falls below 70 mg/dL and may include:
- Nausea.
- Extreme
hunger.
- Feeling nervous or jittery.
- Cold, clammy, wet
skin and/or excessive sweating not caused by exercise.
- A rapid
heartbeat (tachycardia).
- Numbness or tingling of the fingertips or
lips.
- Trembling.
Moderate hypoglycemia
If blood
sugar continues to fall, the nervous system will be affected. Symptoms usually
develop when the blood sugar falls below 55 mg/dL and may include:
- Mood changes, such as irritability, anxiety,
restlessness, or anger.
- Confusion, difficulty in thinking, or
inability to concentrate.
- Blurred vision, dizziness, or
headache.
- Weakness, lack of energy.
- Poor
coordination.
- Difficulty walking or talking, such as staggering or
slurred speech.
- Fatigue, lethargy, or drowsiness.
Severe hypoglycemia
The symptoms
of severe low blood sugar develop when blood sugar falls below 35-40 mg/dL and
may include:
- Seizures or convulsions.
- Loss of
consciousness, coma.
- Low body temperature (hypothermia).
Prolonged severe hypoglycemia can cause irreversible brain
damage and heart problems, especially in people who already have
coronary artery disease. If emergency medical
treatment is not provided, severe hypoglycemia can be fatal.
Some
medicines may mask symptoms of low blood sugar,
including
beta-blockers, which are often used to treat heart
conditions and
high blood pressure.
What to think about
Different people may develop
symptoms of mild, moderate, or severe hypoglycemia at varying blood sugar
levels. Although the blood sugar levels listed above are typical, they may not
apply to everyone. If your blood sugar drops suddenly, you may develop symptoms
even if your level is in the normal range.
A number of medical
conditions can cause symptoms similar to those of hypoglycemia. Your doctor
will use blood tests and other measures to make sure another condition isn't
causing your symptoms.