Blood sugar concentration or blood sugar (glucose) level is the amount of glucose (sugar) present in our blood. Our body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mmol/L (64.8 and 104.4 mg/dL). The human body naturally tightly regulates blood glucose levels as a part of metabolic homeostasis.
The mean normal blood glucose level in humans is about 4 mmol/L (72 mg/dL), however, this level fluctuates throughout the day. Glucose levels are usually lowest in the morning, before the first meal of the day and rise after meals for an hour or two by a few grams.
Blood sugar levels outside the normal range may be an indicator of a medical condition. A persistently high level is referred to as hyperglycemia; low levels are referred to as hypoglycemia.
After checking many sources, we found that that there is a variation in the values considered by some as normal. Summarizing the results, including those published by the American and Canadian Diabetes Associations are as follows and where fasting is usually meant as an overnight 8 hour period without food or liquids other than water.
Fasting blood sugar levels measured after about 8 hours without food or drink other than water should be less than 6.0 mmol/L (108 mg/dL) but no lower than 4.0 mmol/L (72 mg/dL).
Two-hours after a meal blood sugar levels should be 5.0 to 8.0 mmol/L (90 to 144 mg/dL)
Within 3 hours after a meal they should be back to normal levels. If you are a diabetic, you will probably not get blood sugar level very often below 6.0 mmol/L (108 mg/dL)
Blood glucose measurement units: American blood laboratories use a different version of the metric system than does most of the rest of the world. American system (mg/dL) generally uses mass per unit volume (milligrams per deciliter of blood). On the other hand the SI system (mmol/L) – in Canada, UK, Australia, Europe and other countries – uses moles per unit volume (millimoles per liter of blood).
Prognosis: Diabetes can lead to serious complications and premature death but those who have diabetes can take steps to control the disease and lower the risk of complications. With good blood glucose and blood pressure control, many of the complications of diabetes can be prevented. Studies have shown that strict control of blood sugar, cholesterol and blood pressure levels in persons with diabetes helps reduce the risk of kidney disease, eye disease, nervous system disease, heart attack and stroke.