Hypoglycemia, also known as a 'hypo' or low blood sugar, is a fall in blood sugar to levels below normal. This may result in a variety of symptoms including a feeling of hunger, fatigue, sweating, shakiness and weakness. In patients diagnosed with diabetes, these symptoms can be life threatening.


The glucose level that defines hypoglycemia is variable. In people with diabetes, levels below 3.9 mmol/L is diagnostic. In adults without diabetes, symptoms related to low blood sugar, low blood sugar at the time of symptoms and improvement when blood sugar is restored to normal confirm the diagnosis. Otherwise, a level below 2.8 mmol/L after not eating or following exercise may be used.