Blood sugar regulation cells in the pancreatic islets are among the most well understood and important. If the blood glucose level falls to dangerous levels (as during very heavy exercise or lack of food for extended periods), the alpha cells of the pancreas release glucagon, a hormone whose effects on liver cells act to increase blood glucose levels. They convert glycogen into glucose (this process is called glycogenolysis). The glucose is released into the bloodstream, increasing blood sugar. Hypoglycemia, the state of having low blood sugar, is treated by restoring the blood glucose level to normal by the ingestion or administration of dextrose
Blood sugar level level to a narrow range of about 4.4 to 6.1 mmol/L (79 to 110 mg/dL) (as measured by a fasting blood glucose test). The normal blood glucose level (tested while fasting) for non-diabetics, should be between 3.9 and 7.1 mmol/L (70 to 130 mg/dL). The mean normal blood glucose level in humans is about 5.5 mmol/L (100 mg/dL); however, this level fluctuates throughout the day. Blood sugar levels for those without diabetes and who are not fasting should be below 6.9 mmol/L (125 mg/dL). The blood glucose target range for diabetics, according to the American Diabetes Association, should be 5.0–7.2