Hypoglycemia occurs when blood glucose (blood sugar) drops below normal levels. Generally speaking, the term hypoglycemia is used when the reading on the blood glucose monitor (device that determines the concentration of glucose in the blood) indicates less than 4 mmol/L. Severe hypoglycemia occurs when values are below 2.8 mmol/L. Glucose is an essential sugar that our body requires to function correctly and the main source of energy for the brain. An insufficient amount of blood glucose can therefore interfere with the proper functioning of the body and can even be fatal.


In healthy individuals, hypoglycemia can occur at any time, regardless of age. Nevertheless, this condition is more common in those with diabetes, a disease characterized by abnormally high glucose levels in the blood. Diabetics take drugs to reduce blood glucose which helps them achieve and maintain normal levels. However, some situations can cause diabetics to experience a greater drop than intended, resulting in hypoglycemia.

The common causes of hypoglycemia include:

  • Vigorous physical exercise or having been more active than normal
  • Significant stress
  • Certain medications
  • Certain medications
  • Not having eaten (fasting or too restrictive a diet), having waited too long to eat or not having eaten enough
  • Significant intake of alcohol on an empty stomach
  • In diabetics: taking a higher dose of antidiabetic medication (example: insulin)
  • In non-diabetics: ingesting a greater amount of sugar (candy, pastries, chocolate, etc.) can trigger an exaggerated response by the body to reduce blood glucose.


Hypoglycemia can develop slowly but can also appear suddenly and progress quickly. Symptoms vary from person to person and are even non-existent in some cases. They are usually more serious, however, in diabetics. Symptoms become more numerous and severe as blood sugar levels drop.

Mild to moderate symptoms (blood glucose between 2.8 and 4 mmol/L)

  • Nightmares
  • Confusion
  • Difficulty speaking
  • Difficulty concentrating
  • Dizziness
  • Weakness
  • Hunger
  • Irritability
  • Nausea
  • Nervousness
  • Headache
  • Abdominal discomfort
  • Visual disturbances
  • Pallor
  • Palpitations
  • Cold skin
  • Tingling
  • Difficulty sleeping, disturbed sleep
  • Night sweats
  • Sweating Tremor

Severe symptoms (blood glucose below 2.8 mmol/L)

  • Fatigue
  • Drowsiness
  • Loss of consciousness
  • Seizures
  • Coma


The key to prevention resides in healthy eating throughout the day, engaging in moderate physical activity and adequate stress management. Those who are not diabetic are advised to eat smaller meals more frequently.

Any person with diabetes or prone to hypoglycemia should carry a source of fast-acting glucose on their person at all times. Friends and loved ones should be instructed on how to treat hypoglycemia. If you are hypoglycemic, it is also important for you to notify your pharmacist or physician since hypoglycemia can result from the improper management of antidiabetic medication, something that can be resolved with a simple medication adjustment.

What if symptoms appear?

As soon as the first signs of hypoglycemia appear:

  • Check blood glucose with a blood glucose monitor as soon as possible.
  • If blood sugar is less than 4 mmol/L (or if you cannot check), it is important to take action:
  • Immediately ingest one dose of fast-acting glucose (see table below).
  • Wait 15 minutes, then check blood glucose a second time, if possible.
  • If blood glucose is still less than 4 mmol/L, take a second dose of fast-acting glucose.
  • Repeat steps 2 and 3 until blood glucose levels have exceeded or are equal to 4 mmol/L.
  • Once normal blood glucose levels have been reached, and if a meal is not scheduled in the next hour, it is important to have a snack that contains both carbohydrates (15 g of glucose) and protein (ex: 4 crackers with cheese or peanut butter).
  • If blood glucose is less than 2.8 mmol/L, a higher dose of fast-acting glucose (20 g) is recommended (see table below) and the patient should consult a physician.

If an individual loses consciousness, glucagon, a hormone that increases blood sugar, can be injected. If this should occur, call 911 or emergency services.

Sources of fast-acting glucose (15 g) (blood sugar below 4 mmol/L)

Glucose tablets:

  • 3 tablets of glucose BD or
  • 4 tablets of Dex4 or
  • 5 tablets of Dextrosol or
  • 7 tablets of Glucosol

1 tube of Insta-glucose ®

½ cup (125 mL) of fruit juice or ½ cup of (125 mL) regular soft drink (never diet soft drinks)

3 teaspoons or 1 tablespoon of sugar, jam, caramel, honey or molasses

3 packets of white sugar diluted in water (never artificial sweeteners such as Splenda®)

5 LifeSavers® candies

Higher sources of fast-acting glucose (20 g) (blood sugar below 2.8 mmol/L)

Glucose tablets:

  • 4 tablets of glucose BD or
  • 5 tablets of Dex4 or
  • 7 tablets of Dextrosol or
  • 9 tablets of Glucosol

¾ cup (175 mL) of fruit juice or ¾ cup (175 mL) regular soft drink (never diet soft drinks)

4 teaspoons of sugar, jam, caramel, honey or molasses

4 packets of white sugar diluted in water (never artificial sweeteners such as Splenda®)

7 LifeSavers® candies

Note: Chocolate, pastries and whole fruits are not the best choices when treating hypoglycemia. These sugars are considered too slow-acting.