Glucose is a simple sugar and is the main free sugar found circulating in the blood of humans. According the the New World Encyclopedia, glucose is the fuel of choice for the brain, nervous system and red blood cells. Glucose levels must stay within a certain range. Both high and low blood glucose levels can be dangerous.
Sources
Glucose comes from two major sources. Glucose comes from the foods we eat. Food is broken down and digested in the intestines. After the foods are broken down, they are absorbed, partially as glucose. Glucose enters the bloodstream directly via this method. Glucose is also made in the liver. The liver can respond to blood glucose levels and make more glucose if necessary. This is a very important regulatory process that occurs within the body and helps keep the body systems stable.
Function
Glucose is vital for normal function of the human body. As mentioned, it is the preferred fuel source for red blood cells, the nervous system and the brain. Low levels of glucose can impair brain and nervous system function. Glucose is a major source of energy for almost all of the cellular activities that occur within the body. Glucose can be used immediately as an energy source or stored as glycogen for later use. Glycogen can be stored in both the liver and muscle.
Hypoglycemia
When blood glucose levels drop below normal, hypoglycemia occurs. Hypoglycemia literally means low blood sugar. A number of symptoms can be associated with hypoglycemia. These can include hunger, confusion, sleepiness, weakness and shakiness. Diabetic individuals are especially prone to hypoglycemia. It is important that they closely monitor their diet, blood sugar levels, and physical activity to ensure that hypoglycemia does not occur. When hypoglycemia occurs, it is important to get an instant source of glucose such as honey, glucose tablets, 1/2 cup of a regular soft drink or 5 or 6 pieces of hard candy.
Hyperglycemia
Hyperglycemia is the exact opposite of hypoglycemia. Hyperglycemia occurs when blood glucose is too high. According to the American Diabetes Association, high blood glucose can occur when the body does not have enough insulin to regulate glucose levels or cannot use the insulin properly. Frequent urination and increased thirst are classic symptoms of hyperglycemia. Exercise and dietary modifications can help lower blood sugar levels. If these do not help, medications may be required. Hyperglycemia can be dangerous and life threatening if left untreated.
Diabetes
A New York Times article describes diabetes as a "chronic disease marked by high levels of sugar in the blood". There are three types of diabetes. With type I diabetes, the body make very little or no insulin. Type I diabetes is generally diagnosed in children. Type II diabetes is sometimes called adult-onset diabetes, because it is mostly diagnosed in adults. Type II diabetics make insulin, but they cannot utilize it as healthy individuals do. Type II diabetes is much more common than type I. Gestational diabetes is the third type of diabetes. Gestational diabetes occurs in mothers when they are pregnant. The high blood sugar can occur at any time during the pregnancy and in women who do not have a prior diagnosis of diabetes. Although gestational diabetes usually goes away after delivery, women that have gestational diabetes are at an increased risk of developing type II diabetes later in life.
