For people living with diabetes treated with insulin, hypoglycemia can be an ongoing concern

What is hypoglycemia (low blood sugar)?

The medical definition of "low blood sugar" is when your blood sugar level goes below 4 mmol/L.1 When this occurs, you might start to feel a variety of things, which can include, but is not limited to:1,2

  • Sweating

  • Hunger

  • Headache

  • Blurred vision

  • Extreme tiredness and paleness

  • Dizziness

  • Trembling

  • Mood change

It is important to note that not everyone who experiences low blood sugar will experience the same symptoms, or the same severity of symptoms.2 You might feel hungry, but someone else could begin to have blurred vision—be sure to record any symptoms you might feel you are experiencing, and talk with your healthcare provider about them.

To determine if there is potential that low blood sugar can be affecting you, take the low blood sugar check below:

Has your blood glucose level ever dropped below 4 mmol/L in the past 3 months?



Have you experienced shaking, sweating, dizziness, tiredness, or headaches?



Have you experienced low blood sugar during the night?



Have you experienced nighttime low blood sugar that caused symptoms such as nightmares and sweating which woke you up during the night?



Are you frequently snacking to prevent or treat low blood sugar?



Is the possibility of experiencing low blood sugar often on your or your family’s mind?



If you answered "yes" to any of the above questions, speak with your healthcare professional. There are ways to help manage your risk of hypoglycemia. It is safer and more effective to prevent low blood sugar than to treat it.3

Sometimes, you may not even know you are experiencing low blood
sugar because not everyone experiences symptoms. Regular blood
sugar monitoring can help you know if you are at a healthy sugar
level, and help prevent a silent state of hypoglycemia.2,3

When can low blood sugar occur?

Low blood sugar can happen at any time and in any daily situation or environment. It can happen during the day, just as it can happen during the night. People may not realize they have had a hypoglycemic episode because some of the early symptoms, like feeling hungry, are quite mild and ordinary. But without action, symptoms could worsen. Watch for the following warning signs and symptoms.1,2,4,5







Mood changes



Night sweats

Tiredness, irritability
upon waking


A lower than normal
pre-breakfast blood
sugar level

A higher than usual
pre-breakfast blood
sugar level


Impaired thinking
the next day

Sluggishness the
next day

Low blood sugar can occur at any time and any place—including when you are driving. It is important for people with diabetes treated with insulin to take appropriate precautions before getting behind the wheel, which include:3

  • Considering measuring blood glucose immediately before driving and at least every 4 hours while driving

  • Always keeping an emergency supply of fast-acting carbohydrate tablets (e.g., dextrose tablets) within easy reach

  • Not starting to drive when blood glucose is below 4 mmol/L

Why does low blood sugar occur?

A) When blood sugar levels are high (like after a meal), insulin is released, allowing cells to absorb sugar and, in turn, allowing your body to work properly. Extra glucose gets stored in the liver, where it is readily available to be used if needed.6

B) When blood sugar levels are low (like between meals or after exercise), another hormone released from the pancreas instructs the liver to release stored sugar.6

Below are a few reasons that could cause you to have low blood sugar:2

EXERCISE – Trying a new, more intense activity, exercising more than usual, exercising longer than usual.

ALCOHOL – Drinking alcohol, especially without eating, prevents the stored sugar from being released from your liver.

MEDICATION – Taking either the wrong type of medication, the wrong dosage of medication prescribed by your healthcare provider, or taking too much medication in relation to your other activities and food intake.

PHYSIOLOGY – A chronic illness of the kidney or liver, or a hormone deficiency could also lead to low sugar levels.

Getting the balance right

The key to managing diabetes is getting the right balance
between food, medication and physical activity.

It’s important to know that just because your blood sugar levels
and A1C are decreasing towards the goals you’ve set with your
healthcare providers, it does not mean there is an increased risk
of experiencing a low blood sugar event. Low blood sugar can
occur in anyone with diabetes, regardless of their A1C.7

Who does low blood sugar occur in?

Low blood sugar can happen to anyone with diabetes. While people with type 1 diabetes were more likely to experience a low blood sugar event, it was not unusual for people with type 2 diabetes to also experience low blood sugar.7* Additionally, low blood sugar had been observed to be more prevalent in people with type 1 diabetes who have a history of previous hypoglycemia. For people with type 2 diabetes, previous hypoglycemia history and long history of insulin treatment were established to be factors increasing the prevalence of low blood sugar.3

Many people with diabetes taking insulin do not report low
blood sugar to their physicians.7 However, it is important that
healthcare providers know about low blood sugar because they
can suggest ways to minimize the risk of future events.

Did you know that low blood sugar events are experienced…7*

* The Canadian cohort of a non-interventional, multicentre, 6-month retrospective and 4-week prospective study, using self-assessment questionnaires and patient diaries, included 498 patients, aged ≥18 years with type 1 diabetes (n=183) or type 2 diabetes (n=315), treated with insulin for >12 months. The primary endpoint was the proportion of patients experiencing at least one hypoglycemic event during the observational period. In the 4-week prospective period, 64.2% of people with type 2 diabetes and 95.2% of people with type 1 diabetes confirmed having experienced a low blood sugar episode.

Remember, you are not alone—there are many people who are
affected by low blood sugar. With many resources available and
a supportive diabetes healthcare team, it is possible to reduce,
prevent, and manage hypoglycemia.

Why does low blood sugar matter?

For people with diabetes, low blood sugar can be a sign that the person’s diabetes is not being well controlled.1 Very low blood sugar may lead to unconsciousness, falls or possibly seizures.1 Additionally, hypoglycemia unawareness can occur from repeated low blood sugar events, which can lead to a person being unable to feel the signs or symptoms of low blood sugar, potentially increasing health risks.4,6

Aside from the above and low blood sugar symptoms,
what can happen after a low blood sugar event?

Many people with diabetes:

Fear more episodes

after experiencing hypoglycemia

After experiencing a low blood sugar episode, people with type 1 diabetes and people with type 2 diabetes were both found to have an increased fear for future low blood sugar episodes—one episode may be all it takes.8 Low blood sugar has also been determined to have a negative economic and social impact for people with type 1 and type 2 diabetes.9

In order to help prevent some of these above outcomes, monitoring your own blood sugar levels (self-monitoring) and talking with your healthcare provider, are options to consider. They are great resources who can give you a lot of useful information, and help you create a personalized plan for your blood sugar management.1,6

One way to monitor your blood sugar levels yourself is by self-monitoring. This gives you the responsibility to record any information which relates to your own personal blood sugar profile. Keeping track of your blood sugar levels and any triggers that lead to low blood sugar can help you and your healthcare providers identify patterns and ways to help prevent or manage low blood sugar events. Information to note can include:2,6

  • When you have low blood glucose

  • What signs and symptoms you experience

  • When your signs and symptoms of low blood sugar disappear

  • When you take medication for your low blood glucose or diabetes

  • When you eat in order to raise your blood glucose levels

  • When and how much activity you are doing can also be recorded

  • What you think could have led to your low blood sugar episode

  • How you felt after your blood sugar levels reovered and how the event impacted you

Doing so will not only keep your blood glucose levels in check, but it will also help your healthcare providers understand when and why these events are occurring so they can help prevent future low blood sugar events.

Low blood sugar and the fear of low blood sugar can be a
source of anxiety among many people living with diabetes.8
However, your healthcare provider can provide you with
strategies to reduce your risk of experiencing low blood sugar.

One is one too many

What can you do about low blood sugar?

If you realize you are experiencing low blood sugar, it can be treated. Consuming 15 g of carbohydrates will relieve symptoms associated with hypoglycemia in most people.1

Examples of 15 g of carbohydrates:

  • 15 g of glucose in the form of glucose tablets (preferred choice)

  • 15 mL or 3 packets of table sugar dissolved in water

  • 150 mL of juice or regular soft drink

  • 6 LifeSavers®

  • 15 mL of honey (do not use for children less than 1 year old)

Wait 15 minutes, and then check your blood glucose again. If it is still low:

  • Treat again; wait 15 minutes, check your blood sugar. Continue these steps until your blood sugar is above 4 mmol/L

When your blood sugar is above 4 mmol/L:

  • If your next meal is more than one hour away, or you are going to be active, eat a snack with 15 g of carbohydrates and a protein source

  • Wait 40 minutes after treating low blood sugar before driving

Think about why your blood glucose went low and make the necessary changes to avoid
low blood glucose again.

LifeSavers® is a trademark of the Wm. Wrigley Jr. Company.


  • Diabetes Canada. Lows and highs: blood glucose levels. 2018. Available at: Retrieved May 17, 2018.

  • Mayo Clinic. Diabetic hypoglycemia. 2015. Available at: Retrieved May 17, 2018.

  • Diabetes Canada Clinical Practice Guidelines Expert Committee. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes. 2018; 42(suppl 1):S1-S325.

  • Canadian Diabetes Association. Diabetes Dictionary. 2016. Available at: Retrieved May 17, 2018.

  • WebMD. Dawn Phenomenon and the Somogyi Effect – Overview. 2015. Available at: Retrieved May 17, 2018.

  • Mayo Clinic. Hypoglycemia. 2015. Available at: Retrieved May 17, 2018.

  • Aronson R, et al. Can J Diabetes. 2018;42(1):11-17.

  • Leiter LA, et al. Can J Diabetes. 2005;29(3):186-192.

  • Brod M, et al. Value Health. 2011;14(5):665-671.