Diabetes-Related High and Low Blood Sugar Levels - Topic Overview
High blood sugar usually
develops slowly over a period of hours to days. But missing a dose of insulin
can cause a rapid rise in blood sugar levels. Blood sugar levels just above
your target range may make you feel tired and thirsty. If your blood sugar
level stays higher than normal for weeks, your body will adjust to that level,
and you may not have as many
symptoms of high blood sugar.
don't monitor your blood sugar regularly or you don't notice the symptoms of
high blood sugar, you usually will have time to treat high blood sugar so that
you can prevent high blood sugar emergencies. Three things can help you prevent
high blood sugar problems:
- Test your blood sugar often, especially if you
are sick or are not following your normal routine. You can see when your blood
sugar is above your target range, even if you don't have symptoms of high blood
sugar such as increased thirst, increased urination, and fatigue. Then you can
treat it early, preventing an emergency.
- Call your doctor if you
have frequent high blood sugar levels or if your blood sugar level is
consistently staying above your target range. Your medicine may need to be
adjusted or changed.
- Drink extra water or non-caffeinated,
non-sugared drinks so you will not be dehydrated. If your blood sugar continues
to rise, your kidneys will increase the amount of urine produced, and you can
Complications of high blood sugar can cause serious
problems, including coma and death. Over time, high blood sugar can damage your
eyes, heart, kidneys, blood vessels, and nerves.
blood sugar occurs when the sugar (glucose) level in your blood drops below
what your body needs. Not eating enough food or skipping meals, taking too much
medicine (insulin or pills), exercising more than usual, or taking certain
medicines that lower blood sugar can cause your blood
sugar to drop rapidly. Do not drink alcohol if you have problems recognizing the early signs of low blood sugar.
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.