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Symptoms of Low Blood Sugar


Some young children with diabetes can't recognize symptoms of low blood sugar. Others can, but not every time. To be safe, parents need to do a home blood sugar test whenever they suspect low blood sugar in a child.

Mild low blood sugar

If your blood sugar drops below 70 mg/dL, you may have symptoms of mild low blood sugar, such as:

  • Sweating (almost always present).
  • Feeling nervous, shaky, and weak.
  • Extreme hunger and slight nausea.
  • Dizziness and headache.
  • Blurred vision.
  • Fast heartbeat.

These symptoms may go away shortly after you eat food that contains sugar.

If you have had diabetes for many years, you may not always have symptoms of mild low blood sugar.

Moderate low blood sugar

If your blood sugar continues to drop, your behavior may change. Symptoms of moderate low blood sugar may include:

  • Inability to concentrate.
  • Confusion and irritability.
  • Slurred speech.
  • Unsteadiness when standing or walking.
  • Muscle twitching.
  • Personality changes, such as anger or crying.

Severe low blood sugar

Severe low blood sugar may cause:

  • Seizure.
  • Loss of consciousness (coma).
  • Stroke.
  • Death.

Low blood sugar at night

If your blood sugar drops while you are sleeping, your partner or other family members may notice that you are sweating and behaving differently. Signs of low blood sugar at night (nocturnal hypoglycemia) include:

  • Restlessness.
  • Making unusual noises.
  • Sleepwalking.
  • Nightmares.
  • Sweating.

You may wake up in the morning with a headache if your blood sugar was low during the night.

Hypoglycemic unawareness

Hypoglycemic unawareness means not being able to recognize low blood sugar until the symptoms are serious. Most people have symptoms if their blood sugar drops below 70 mg/dL. But if you have hypoglycemic unawareness, the only symptom you may have is confusion. Or you may become unconscious before anyone realizes you have low blood sugar.

You may have hypoglycemic unawareness if you:

  • Can't feel when your blood sugar is low.
  • Have had low blood sugar many times.
  • Have had diabetes for a long time.

If you have hypoglycemic unawareness, test your blood sugar often, especially before activities like driving a car. Keep quick-sugar foods like glucose tablets or hard candy with you. Teach your friends and family how to treat low blood sugar. And if you take insulin, always carry glucagon with you.


Current as of: October 2, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.


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