Diabetes is characterized by hyperglycemia, which is abnormally high levels of sugar (glucose) in the bloodstream, so everyone with type 1 and type 2 diabetes has experienced hyperglycemia. Hyperglycemia occurs when the body is not properly processing or using glucose, which is the case when insulin levels are low or nonexistent, and normally the excess amounts of glucose in the body is converted to glucogon or fat and stored for later use. Catabolic hormones such as glucagon, growth hormone, catecholamines, thyroxine and somatostatin, will increase blood sugar levels, but only insulin, which is an anabolic hormone, will decrease blood glucose levels. Since insulin is responsible for maintaining safe and healthy blood sugar levels in your body, if it is no longer present or not being produced in sufficient quantities, excess glucose will remain in your bloodstream. The excess glucose in your blood, if allowed to continually increase without treatment, will not only eventually cause serious complications, it can even kill you!
The standard unit for measuring blood glucose levels around the world is millimoles per liter (mmol/L), but in the U.S. blood glucose levels are measured in milligrams per deciliter (mg/dL). Blood sugar levels are usually at their lowest in the morning and are commonly known as "fasting blood sugar levels" and should be tested first thing upon waking, before breakfast. In people without diabetes the normal range of blood glucose levels eight to twelve hours after their last meal is between 70 to 100 mg/dL (3.8 to 5.5 mmol/L). Glucose levels rise by a few grams after meals for about an hour or two, so it is usually tested two hours after the end of the meal. In those without diabetes, the normal blood sugar levels after a meal is usually between 135 to 140 mg/dL (7.5 to 7.8 mmol/L). Keeping blood sugar levels under control is the cornerstone of preventing complications of diabetes and fortunately technology has produced a wide range of very accurate and convenient blood glucose meters, making it safe and easy to test your blood glucose level.
As listed in the "Effects of Diabetes" section of this web site, high glucose levels if left untreated for long periods of time can cause serious complications, most noticeably to the eyes, kidneys, and nerves among others. In the short term high blood glucose will not cause any damage to your organs, however they will cause you to feel fatigued, unusually thirsty, urinate quite frequently, make you more susceptible to infections and cause blurred vision. Listed below are some of what could happen when blood glucose reaches certain levels.
1. Blood glucose above 180 to 200 mg/dL (10 to 11 mmol/L) will exceed the capacity of the kidneys to reabsorb glucose and they will begin to the pass the excess glucose into the urine, creating a condition known as "glycosuria" ( the presence of sugar in urine ).
2. Because type 1 diabetics are prone to a condition known as "Diabetic ketoacidosis" they should test their urine for "ketones" when or if their blood glucose level rises above 240 mg/dL (13.2 mmol/L). Diabetic ketoacidosis occurs almost exclusively among type 1 diabetics and is a very serious condition in which excessively high blood sugar levels, along with a lack of insulin, force the body to break down fat for energy. Diabetic ketoacidosis produces increased levels of toxic acids in the blood called ketones, which if not treated right away can lead to coma or even death.
3. Sustained blood glucose levels around the 400 to 500 mg/dL (22 to 27.5 mmol/L) has been associated with some alteration in mental function. If left untreated for a long time, mental changes can be seen as well.
4. A condition known as diabetic hyperosmolar syndrome occurs if blood glucose levels are allowed to rise above 600 mg/dL (33 mmol/L). This is when your blood glucose has reached such a high level that it becomes thick and syrupy. A filtering process is triggered when the excess glucose passes from your blood to your urine, drawing extreme amounts of fluid from your body. Life-threatening dehydration can occur if prompt medical attention is not obtained.
5. Any sustained glucose levels 600 mg/dL (33 mmol/L) and above should only be found in people who are unaware that they are experiencing hyperglycemia. At such high levels of blood glucose, a person that is not diagnosed and treated or diabetics that are not properly following treatment and allow their glucose levels to reach this point, run the risk of diabetic coma or even death.
• Fatigue or drowsiness
• Frequent urination
• Unexplained weight loss
• Blurry vision
• Excessive hunger and thirst
• Dry mouth and skin
• Wounds or infections that heal slower than normal
• Excessive amounts of food
• Missing or skipping insulin doses/diabetic medication
• Insufficient doses of insulin/diabetic medication
• Stress (Stress can cause blood glucose levels to rise)
• Too little or no exercise
• Insulin resistance - A condition where the body becomes resistant to the actions of insulin (Generally found in Type 2 Diabetics)
Hyperglycemia/hypoglycemia can be life threatening, so people with diabetes must maintain a consistent schedule of monitoring their blood glucose levels to insure that they can manage them within tolerable levels. However even with close monitoring, blood glucose could sometimes temporarily reach levels of 300 mg/dL (16.5 mmol/L) or more in diabetics, so testing their blood glucose levels at regular intervals is very important.