In the morning after fasting exercise and then test the blood glucose level, normal people will generally appear to rise temporarily, the diabetic population will generally appear to fall. 1. Rise: Under normal circumstances, the normal value of fasting blood glucose level is 3.9~6.1 mmol per liter, in the process of exercise the body fat is broken down into glucose, at this time the level of glucagon increases, so the blood glucose level will rise temporarily after fasting exercise, but the blood glucose level of the normal people is still fluctuating between the above values. 2. Decrease: For diabetic patients, exercise after fasting will generally reduce blood glucose levels, because the use of glucose by peripheral tissues and muscles increases significantly after exercise, so that glycogen can not be broken down, which leads to a decrease in blood glucose levels. Patients with diabetes need to test their blood glucose levels before exercising on an empty stomach. Fasting blood glucose levels above 13.9 mmol/L are not recommended for exercise and may be dangerous, while fasting blood glucose levels below 5.6 mmol/L are recommended to eat and drink appropriately before exercising in order to avoid hypoglycemia. For patients with diabetes mellitus, it is recommended to consult the endocrinology department of regular hospitals for dietary health education.