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Back to Basics: How to Recognize and Treat Hypoglycemia (Low Blood Sugar)

Hypoglycemia or low blood sugar (low blood glucose) is when the level of glucose (sugar) in your blood drops below 4 mmol/L.

Hypoglycemia tends to happen more often in people using insulin and those who use oral insulin secretagogue medications. Insulin secretagogues include gliclazide (Diamicron® and Diamicron MR®), glyburide (DiaBeta®), glimepiride (Amaryl®), and repaglinide (GlucoNorm®).

How to Recognize and Treat Low Blood Sugar | Beyond Diabetes Nutrition - Lucy Zhang, Registered Dietitian

What are the signs and symptoms of low blood sugar?

Symptoms of low blood sugar can come on quickly. It is important to remember that you likely will not experience all symptoms listed and that symptoms can differ from person to person. Sometimes, people may not notice any symptoms at all.

Signs and Symptoms of Hypoglycemia Low Blood Sugar | Beyond Diabetes Nutrition - Lucy Zhang, Registered Dietitian

Mild Hypoglycemia

Think “fight or flight” response. You are able to self-treat the low.

  • Trembling

  • Heart palpitations (heart thumping)

  • Sweating

  • Anxiety

  • Hunger

  • Nausea

  • Tingling

If low blood sugar occurs while you are sleeping, signs and symptoms may include:

  • Disturbed sleep

  • Weird dreams

Moderate Hypoglycemia

The brain does not get enough glucose. Think “similar to being drunk”. You are able to self-treat the low.

  • Difficulty concentrating

  • Confusion

  • Weakness

  • Drowsiness

  • Vision changes

  • Difficulty speaking

  • Headache

  • Dizziness

Severe Hypoglycemia

When the brain is starved of glucose. Usually, blood sugar is <2.8 mmol/L. Requires the assistance of another person to administer glucagon. Call 911.

  • Seizures

  • Coma

How to treat low blood sugar?

How to Treat Hypoglycemia Low Blood Sugar | Beyond Diabetes Nutrition - Lucy Zhang, Registered Dietitian

Step 1

If you suspect you may be having low blood sugar, it is a good idea to confirm with your glucometer. I often tell clients if they are feeling unwell, it’s a good idea to check blood sugar to rule out low blood sugar.

Step 2

If blood sugar is less than 4.0 mmol/l, it is important from a safety perspective to treat the low with 15g of fast-acting sugar.

Examples of 15g of fast-acting sugar:

  • Glucose tablets (Dex4) - Remember, FOUR tablets is equal to one treatment

  • ⅔ cup (150mL) of regular juice OR regular pop. Diet juice or pop will not work!

  • 1 tablespoon of honey

  • 1 tablespoon of sugar dissolved in water

  • Hard candies, jelly beans, or gumdrops (e.g. 6 Life Savers OR 2 rolls of Rocket Candy)

Step 3

After treating with 15g of fast-acting sugar, wait 15 minutes and check blood sugar again. You want to make sure that blood sugar is now above 4.0 mmol/L.

  • If YES - move on to Step 4

  • If NO - Repeat Steps 2 and 3

Step 4

Have food within one hour. If your next meal is more than an hour away, have a snack. This should include a source of carbohydrates and protein. The purpose of this food is to prevent blood sugar from dropping low again.

What causes low blood sugar?

Low blood sugar is usually caused by a mismatch between insulin and carbohydrate intake - this can be the result of:

  • Eating less than planned

  • Eating later than planned

  • A more physically active day.

  • Alcohol intake - even if that drink was from the night before!

Episodes of low blood sugar can be scary, they are also a safety concern! If you are having episodes of low blood sugar, be sure to let your healthcare team know so that you can work together to reduce the frequency of lows.


Canadian Diabetes Association. Building Competency in Diabetes Education: The Essentials (5th Ed.) Toronto: Canadian Diabetes Association. 2019.

Diabetes Canada. Hypoglycemia Low Blood Sugar in Adults. Toronto: Diabetes Canada; 2018.

Yale J, Paty B, Senior PA. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Hypoglycemia. Can J Diabetes. 2018;42(Suppl 1):S104-S108.




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