Glucose is a simple sugar that can be converted to energy by living cells. The carbohydrates you consume must be converted to glucose before they can be utilized by your body, because glucose is the preferred source of fuel for your cells. When people mention blood sugar levels, they are referring to the amount of glucose in the bloodstream. Impaired glucose metabolism, such as that which occurs in diabetes or metabolic syndrome, usually leads to adverse health consequences.
Blood Sugar Variation
It is normal for your blood glucose measurement to change throughout the day, and it can vary significantly from one day to the next. Your glucose level is naturally lower following a period of fasting, and it typically falls in response to exercise because active muscles need more energy and absorb glucose from your bloodstream. Whenever you eat, your blood glucose increases as carbohydrates are digested and absorbed from your intestine. A meal that is rich in sweets will increase your blood sugar more rapidly and dramatically than a meal consisting of protein or complex carbohydrates.
Insulin Function
When you consume a meal, the carbohydrates in your food are digested and converted to glucose, which is then absorbed into your bloodstream. Special cells in your pancreas detect the additional glucose in your blood and secrete a hormone called insulin. One of insulin's actions is to stimulate the utilization of glucose, particularly by the cells in your muscles, liver and fat tissue. Once inside these cells, glucose can be metabolized for energy, or it can be converted to glycogen or fat and stored for future use. Insulin plays a key role in keeping your sugars within a normal range.
Diabetes Diagnosis
The American Diabetes Association (ADA) gathers information about diabetes and advises health professionals and the general public about the best ways to manage this disease. In 2010 the ADA updated its criteria for diagnosing diabetes and for identifying people who are at risk. According to ADA guidelines, if your blood glucose reading is above 125 following an eight-hour fast, you are diabetic. Likewise, if your sugar is over 200 at any other time and you have symptoms of diabetes -- excessive thirst, frequent urination, unintended weight loss, fatigue or blurred vision -- you have diabetes. A fasting blood glucose between 100 and 125 means you are at increased risk for diabetes. A special test called hemoglobin A1C can now be used to diagnose diabetes. A value above 6.5 is diagnostic of diabetes, whereas a level from 5.7 to 6.4 indicates prediabetes.
Blood Sugar Levels
While it is difficult to keep track of ADA diagnostic criteria, it is fairly simple to keep two numbers in mind: Your fasting glucose level should be below 100, and a random measurement should ideally be less than 140. If you are at risk for diabetes due to family history, obesity or a sedentary lifestyle, see your physician for evaluation and advice. The Centers for Disease Control predicts a tripling of diabetes cases in America by the year 2050, and you could possibly avoid becoming a statistic by following your doctor's advice.
