Blood Sugar Highs and Lows

Hyperglycemia and Hypoglycemia 

Your diabetes care team will tell you what your blood sugar numbers should be. It’s important to know these numbers and to keep your levels within this target range.


Low blood sugar (Hypoglycemia)

Low blood sugar is also called (hypoglycemia). This is the most common side effect of all insulins including NovoLog®, but there are ways to treat low blood sugar. (See the Rule of 15 below.)

If you feel tired or dizzy, or have a headache or mood swings, your blood sugar may be low. According to the American Diabetes Association (ADA), low blood sugar (hypoglycemia) is when your blood sugar falls below 70 mg/dL.

Some people refer to hypoglycemia as having a “hypo”. You may hear this term from your diabetes care team. Download and print the Low Blood Sugar Fact Sheet from Cornerstones4Care® to see a full list of low blood sugar symptoms. Check your blood sugar right away if you have any symptoms of low blood sugar. If you think your blood sugar is low but cannot check it at that time, treat yourself anyway.


Treating Low Blood Sugar

Follow the rule of 15 to help treat low blood sugar:

  • Eat something with 15 grams of carbohydrate (simple sugars, such as 3 to 4 glucose tablets, ½ cup of regular [not diet] soda, or ½ cup of orange juice)
  • Wait 15 minutes and check your blood sugar again
  • If your blood sugar is still low, eat something with 15 grams of carbohydrate again
  • Once your blood sugar is normal, eat a meal or snack to prevent low blood sugar from returning


High blood sugar (Hyperglycemia)

The opposite of a hypo is when your blood sugar is too high. In medical terms, this is called hyperglycemia.

What are some of the causes of high blood sugar (hyperglycemia)?

  • If you have diabetes, you may not have taken enough insulin
  • You ate more than planned or were less active than planned
  • You have stress from an illness such as a cold or the flu
  • You have other stresses, such as family, work, or school issues


What does high blood sugar (hyperglycemia) feel like?

With high blood sugar, you may feel:

  • Very thirsty or hungry
  • Like you need to pass urine more than usual
  • Like your mouth and skin are dry
  • Like your vision is blurry
  • Sleepy


Keep careful track of your blood sugar numbers by writing them down in your Blood Sugar Diary. You can download one here. High or low numbers should always be discussed with your diabetes care team at your next visit.

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Treating hypoglycemia (low blood sugar)

You can treat low blood sugar by eating or drinking something with 15 grams of carbohydrates.

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