Blood Sugar About 4 grams of glucose, a simple sugar, is present in the blood of a 70.3 kg (155 lb) human at all times. The body tightly regulates blood glucose levels as part of metabolic homeostasis. Glucose is stored in skeletal muscle and liver cells in the form of glycogen. The human brain consumes approximately 60% of blood glucose in fasting, sedentary individuals. A persistent elevation in blood glucose leads to glucose toxicity, which contributes to cell dysfunction. Glucose can be transported from the intestines or liver to other tissues in the body via the bloodstream.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 hypoglycemia. Glucose levels are usually lowest in the morning, before the first meal of the day. The mass concentration of glucose C6H12O6 is measured in milligrams per decilitre (mg/dL) in the western parts of Germany, and mg/dL in the Un...