Diabetes-Related High and Low Blood Sugar Levels - Topic Overview
People who lose weight or develop kidney
problems may not need as much insulin or other medicines as they did before
they lost the weight or developed kidney problems. Their blood sugar may drop
too low. Be sure to check your blood sugar often when your body goes
When your blood sugar level drops below 70
milligrams per deciliter (mg/dL), you will usually
have symptoms of low blood sugar. This can develop quickly,
in 10 to 15 minutes.
- If your blood sugar level drops just slightly
below your target range (mild low blood sugar), you may feel tired, anxious,
weak, shaky, or sweaty, and you may have a rapid heart rate. If you eat
something that contains sugar, these symptoms may last only a short time. If
you have diabetes, you may not always notice symptoms of mild low blood sugar.
This is called
hypoglycemia unawareness. If your blood sugar is
well controlled and does not change much during the day, you may have an
increased risk for hypoglycemic unawareness.
- If your blood sugar
level continues to drop (usually below 40 mg/dL), your behavior may change, and
you may feel more irritable. You may become too weak or confused to eat
something with sugar to raise your blood sugar level. Anytime your blood sugar
drops below 50 mg/dL, you should act whether you have symptoms or
- If your blood sugar level drops very low (usually below 20
mg/dL), you may lose
consciousness or have a
seizure. If you have symptoms of severe low blood
sugar, you need medical care immediately.
You may have symptoms of low blood sugar if your blood sugar
drops from a high level to a lower level. For example, if your blood sugar
level has been higher than 300 mg/dL for a week or so and the level drops
suddenly to 100 mg/dL, you may have symptoms of low blood sugar even though
your blood sugar is in the normal range. But if you have had diabetes for many
years, you may not have symptoms of low blood sugar until your blood sugar
level is very low.