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What is Fasting Blood Glucose?

Fasting blood glucose is the amount of glucose (sugar) in your blood after you have not eaten for at least 8 hours. 

This measurement is taken to determine if you have or are at risk for diabetes. 

Blood glucose desirable levels

Fasting blood glucose:

  • 4 to 5.6 mmol/L (without diabetes)
  • 4 to 7.0 mmol/L (for people living with diabetes)

​A1c (average level of blood glucose over the past 3 months):

  • less than 7.0 % for most people living with diabetes

Why is an Abnormal Fasting Blood Glucose Level a Risk Factor?

High levels of blood glucose can increase your risk of getting diabetes and heart disease.

An organ of the body named the pancreas releases a hormone called insulin. Insulin is responsible for lowering blood glucose. It does this by allowing blood glucose to enter the body’s muscle cells. The muscle cells then use the glucose as energy for the body.

Over time, excess weight, especially around the abdomen, can cause “insulin resistance”. Insulin resistance means that your body is no longer able to use insulin effectively to allow blood glucose to be used as energy. This means that high levels of glucose stay in the bloodstream. Find out how having a large waist affects your health »

An A1C between 6.0 % and 6.4 % or fasting blood glucose between 6.1 mmol/L and 6.9 mmol/L indicates “pre-diabetes”. Lifestyle changes including regular exercise and a healthy diet can delay or prevent diabetes by lowering blood glucose levels and improving how the body uses insulin.

If you are living with heart disease or concerned about your risk factors for heart disease, a fasting blood glucose test is recommended. Talk to your doctor about how often this test should occur.

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