Blood Sugar Highs and Lows

Your diabetes care team will tell you what your blood sugar numbers should be. It’s important to know these numbers and to keep them 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® Mix 70/30, but there are ways to help manage 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.

Low blood sugar (hypoglycemia)

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 a Blood Sugar Tracker. You can download one at, or low numbers should always be discussed with your diabetes care team at your next visit.


Seasonal Challenges

Keep your diabetes treatment on track all year long—from making good food choices during fall and winter holidays, to safely get more active during the spring and summer.

Learn How

What's Your Blood Sugar Pattern?

You can use the Pattern Recognition Tool to help you recognize if you are having high or low daily blood sugar readings.

Click Here

Low Blood Sugar (Hypoglycemia)

Download the Low Blood Sugar Fact Sheet from Cornerstones4Care®.

Click Here