Ellen Says:-The blood sugar concentration or blood glucose level is the amount of glucose (sugar) present in the blood of a human or animal.
Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM (mmol/L, i.e., millimoles/liter) (64.8 and 104.4 mg/dL). The human body naturally tightly regulates blood glucose levels as a part of metabolic homeostasis.
Glucose is the primary source of energy for the body's cells, and blood lipids (in the form of fats and oils) are primarily a compact energy store. Glucose is transported from the intestines or liver to body cells via the bloodstream, and is made available for cell absorption via the hormone insulin, produced by the body primarily in the pancreas.
The mean normal blood glucose level in humans is about 4 mM (4 mmol/L or 72 mg/dL, i.e. milligrams/deciliter); however, this level fluctuates throughout the day. Glucose levels are usually lowest in the morning, before the first meal of the day (termed "the fasting level"), 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.
Diabetes mellitus is characterized by persistent hyperglycemia from any of several causes, and is the most prominent disease related to failure of blood sugar regulation.
A temporarily elevated blood sugar level may also result from severe stress, such as trauma, stroke, myocardial infarction, surgery, or illness. Intake of alcohol causes an initial surge in blood sugar, and later tends to cause levels to fall.
Also, certain drugs can increase or decrease glucose levels...
Many factors affect a person's blood sugar level. A body's homeostatic mechanism, when operating normally, restores the blood sugar level to a narrow range of about 82 to 110 mg/dL (4.4 to 6.1 mmol/L). (These levels are in contradiction with the levels cited at the beginning of this article, though the latter are quoted for mammals in general).
Despite widely variable intervals between meals or the occasional consumption of meals with a substantial carbohydrate load, human blood glucose levels normally remain within the normal range. However, shortly after eating the blood glucose level may rise temporarily up to 140 mg/dL (7.8 mmol/L) or a bit more in non-diabetics.
The American Diabetes Association recommends a post-meal glucose level less than 180 mg/dl (10 mmol/L) and a pre-meal plasma glucose of 90–130 mg/dL (5 to 7.2 mmol/L).
The actual amount of glucose in the blood and body fluids is very small. The control mechanism in the human body works on very small quantities of glucose.
In a healthy adult male of 165 lb (75 kg) with a blood volume of 1.3 gal (5 litres), a blood glucose level of 100 mg/dL or 5.5 mmol/L corresponds to about 5 g (0.2 oz or 0.002 gal, 1/500 of the total) of glucose in the blood and approximately 45 g ------(1½ ounces) in the total body water (which includes more than merely blood and will be usually about 60% of the total body weight in men).
(Small sugar packets provided in many restaurants with coffee or tea are about 2.8 grams each.)