Many times, when I meet a person with diabetes for the first time, they are surprised when I ask them if they are having low blood sugars.

‘Sure… but isn’t this just a normal part of having diabetes?’ they might say.

In a word: NO.  There is no reason why a person with diabetes has to be suffering from low blood sugars.

A low blood sugar (also called hypoglycemia) is defined as a blood sugar of less than 4 mmol/L (though if a person has been used to having very high blood sugars, they may experience symptoms at a higher sugar than that.)

When a person has low blood sugars, they may experience palpitations, shakes, or sweating; this is what we call mild hypoglycemia.

If sugars go lower, the person may begin to have an altered level of consciousness, blurry vision, confusion, or drowsiness, because the brain is not getting enough sugar. If the person is able to treat themselves to get out of a low blood sugar, this is called ‘moderate hypoglycemia’.

If the person is not able to help themselves and requires the help of someone else, this is called ‘severe hypoglycemia’. Left untreated, a severe low blood sugar could lead to a heart arrythmia, coma, seizure, or death.


The diabetes medications that can cause low blood sugars are:

  • insulin
  • sulfonylureas (a class of oral medications including gliclazide (Diamicron), glyburide, and related medication repaglinide (Gluconorm))


Low blood sugars are unfortunately very common.  While most episodes are mild, it is downright frightening to consider that in one year, severe hypoglycemia occurs in 38% of Canadian adults with type 2 diabetes using insulin or sulfonylurea, and 54% of Canadian adults who have type 1 diabetes (all of whom use insulin).


Risk factors for hypoglycemia include:

  • kids, teens, pregnant women, and older people
  • hypoglycemia unawareness (people who can’t feel their low sugars)
  • longer duration of diabetes (the ability to feel low blood sugars starts to wane after 10-15 years of having diabetes)
  • decreased kidney function
  • alcohol
  • very tight blood sugar control
  • cognitive impairment (can cause difficult in managing diabetes well)
  • not checking blood sugars regularly
  • missing meals or exercising without altering medication appropriately
  • being on medications that mask low blood sugar symptoms (eg beta blockers)


There are many things that can be done to prevent low blood sugars, such as:

  • Adjust medication regimens to avoid lows
  • Consider newer types of insulin that have a lower risk of low blood sugars
  • consider other type 2 diabetes medications that do not cause low blood sugars
  • continuous glucose monitors that can alarm off if sugars are low or are heading low
  • flash glucose monitoring as another option to monitor sugars more closely
  • relaxing targets for blood sugar control


It is also very important to know how to treat low blood sugars. On that note, there is a new and exciting treatment now available in Canada for treatment of severe low blood sugars – stay tuned for more on a blog post coming soon!  You can also read more about hypoglycemia in the 2018 Diabetes Canada Clinical Practice Guidelines.


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