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 case of a "fight and flight" response. Lastly, cortisol supplies the body with fuel in times of heavy stress. If blood sugar levels remain too high the body suppresses appetite over the short term. Long-term hyperglycemia causes many long-term health problems including heart disease, cancer, eye, kidney, and nerve damage. Blood sugar levels above 300 can cause fatal reactions. Ketones will be very high (a magnitude higher than when eating a very low carbohydrate diet) initiating ketoacidosis. Mayo clinic recommends emergency room treatment above 300 mg/dL blood glucose. The most common cause of hyperglycemia is diabetes. When diabetes is the