The blood glucose level is the amount of glucose, or sugar, in the blood, and is measured in milligrams per decilitre of blood, or mg/dL. These levels do not remain constant, but vary during the day depending on factors such as eating and exercise. Different people have different average glucose levels, as these levels can also be affected by genetic make-up. However, most healthy people will have glucose levels that range between 65 and 105 mg/dL. In diabetes, blood sugar levels remain high until treated.
Defining Glucose
Glucose is a simple, hexose sugar, which can be found in sweet foods, such as fruit, and also in foods such as bread and pasta as carbohydrates, which are long chains of glucose molecules attached together. Glucose is an essential energy source, and is absorbed through the intestines into the blood where it travels to the tissues in the body. In actively-respiring cells, such as brain or muscle cells, glucose is broken down, or oxidized, to release energy. Even in cells that are resting, glucose is needed to produce the energy required for cell growth and repair.
Glucose for Energy
Your body needs energy to perform all the tasks necessary for survival, and a lack of glucose will quickly result in fatigue, while an excess of glucose gives you a feeling of increased vigor. Your body can obtain energy from other large molecules found in foods, such as fats and proteins, but glucose is the most efficient and the preferred source. Because of this, your body has a whole host of mechanisms designed to keep your glucose level within certain limits.
Glucose and Hormones
To maintain a constant blood-glucose level, your body relies on the hormones glucagon and insulin, which are secreted from the pancreas into the blood. Depending on the level of glucose is in the blood, one of these hormones is released to regulate blood sugar levels.
Measuring Glucose
Normal blood glucose levels are hard to define because levels fluctuate depending on whether you've just eaten or slept. Blood tests for glucose are usually performed before you eat, and it is important that you do not eat for eight hours prior to testing.
Diabetics must monitor their own blood glucose levels, often several times a day, to determine what medications they need to take.
Normal Glucose Levels
According to the National Institutes of Health, you should have a fasting glucose level of no higher than 100 mg/dL. If your glucose levels are above 126 mg/dL, a diagnosis of diabetes type II is likely. During the day, levels can fluctuate between about 82 and 110 mg/dL, and it is not uncommon for glucose levels to reach 140 mg/dL after eating. However, the American Diabetes Association strongly recommends that you do not exceed 180mg/dL after a meal.
Glucose and Diabetes
Having persistently high blood glucose levels can increase your chances of developing diabetes, a condition in which the body becomes resistant to its own glucose-lowering hormone, insulin. Abnormally high glucose can cause fatigue, thirst and increased urination. Low blood glucose levels can lead to fatigue, shakiness and a general feeling of weakness. If you are concerned about your blood glucose levels, consult your physician.
