There are many reasons for high blood sugar, the main ones are as follows: the first one, accidental high blood sugar. If you use a lot of sweets before the blood sugar check, of course, you will have a high blood sugar result. So check out is high blood sugar, do not worry too much, check again after a period of time to see the blood sugar results. The second, bad living habits and environment. Nowadays, most young people are very fond of KFC kind of fast food, do not like vegetables and fruits, and long term eating habits may lead to high blood sugar. Negative air ions are natural factors present in the air, still effective in reducing high blood sugar, when the pollution of the environment, resulting in the gathering of negative oxygen ion content in the air, the body does not take in enough negative oxygen ions, which is also an important cause of high blood sugar. The third kind, the high blood sugar caused by other diseases. Coronary heart disease and so on have a close relationship with hyperglycemia, so once it is diagnosed as hyperglycemia, it should be as clear as possible what causes hyperglycemia, so as to treat the symptoms and do a good job of preventing and treating hyperglycemia. Fourthly, after excluding the above triggers that cause hyperglycemia, then hyperglycemia is most likely to be an early symptom of diabetes. At present, the people suffering from diabetes have become younger and younger, and even children’s diabetes has appeared, so diabetic patients must know that high blood sugar should be treated early. Fifth, genetic and other reasons can also lead to hyperglycemia. If it develops into hyperglycemia, it must be controlled in time.