Complications of high blood sugar include damage to the kidneys, nerves, vision, heart and circulatory system, according to Virginia Mason Medical Center. Diabetic ketoacidosis and coma are other possible complications. Frequent monitoring and tight blood sugar control can help to prevent many of the complications.
Fasting blood sugar levels higher than 130 or levels greater than 180 two hours after a meal are high, warns WebMD. In people without diabetes, blood sugars rarely go above 140 after eating. Ongoing and frequent high levels are more likely to cause side effects. Type two diabetics with extremely high blood sugar may develop a potentially deadly condition that prevents their bodies from processing sugar.
Frequent urination and increased thirst are possible signs of high blood sugars, according to the American Diabetes Association. While exercising can help to lower blood sugar levels, if they are over 240, it is essential to check for ketones in the urine before beginning. If there are ketones in the blood, exercise can cause the glucose levels to increase. Effective control often requires a balance of medication, exercise and diet.
Illness and infections can cause a diabetic's blood sugar levels to increase, notes WebMD. When patients experience high stress, their numbers are also likely to be elevated.