Impaired glucose tolerance happens when the pancreas either does not release enough insulin or the cells become resistant to the insulin. Insulin resistance (or impaired glucose tolerance) is classified as a fasting glucose level of 100 mg/dl to 125 mg/dl.
Several factors can contribute to the development of insulin resistance:
The Aging Process
As we age, our body processes can become slower or diminished. The pancreas is no exception. Sometimes the pancreas naturally produces less insulin as we get older.
When a person is overweight, the cells in the body become less sensitive to the insulin that is released from the pancreas. There is some evidence that fat cells are more resistant to insulin than muscle cells.
If a person has more fat cells than muscle cells, then the insulin becomes less effective overall, and glucose remains circulating in the blood instead of being taken in to the cells to be used as energy.
Where the Fat Is At
That spare tire around the midsection is visceral fat or abdominal fat. There is a correlation among abdominal fat, insulin resistance and resulting hyperglycemia. Visceral fat is very resistant to the effects of insulin.
The more fat concentrated in this area, the more insulin resistance occurs. Carrying extra abdominal fat can not only lead to diabetes, it can also increase the risk of high blood pressure and cardiovascular disease.
When someone lives a sedentary lifestyle, using minimal exertion to carry out the tasks of the day, their body doesn't use insulin effectively, resulting in insulin resistance. The American Heart Association recommends 30 minutes of exercise five times a week for heart health. Incorporating this amount of exercise into your life also improves insulin sensitivity and helps with weight loss as well.
Medications that Cause Insulin Resistance
Some medications prescribed for other disorders increase the risk of insulin resistance. Some drugs used to manage bipolar disorder fall into this category. Other medications, such as some steroids, also can lead to insulin resistance.
Genetics and Family History
Native Americans, African Americans, Hispanic Americans, Asian Americans and Pacific Islanders are at a higher risk for developing insulin resistance and type 2 diabetes. A family history of type 2 diabetes also increases the risk.
Is Insulin Resistance Inevitable?
Sometimes insulin resistance can be prevented or reversed. Although insulin production in the pancreas usually cannot be increased in the instance of reduced insulin excretion, weight loss, diet and exercise make a considerable difference in the body's resistance to the insulin that the pancreas is able to is produce.
Gastaldelli, Amalia (2008, May). Abdominal Fat: Does it Predict the Development of Type 2 Diabetes?. American Journal of Clinical Nutrition, 87, Retrieved July 19, 2008, from http://www.ajcn.org/cgi/content/full/87/5/1118
(2007, Oct. 17). Exercise and Fitness. Retrieved July 19, 2008, from American Heart Association Web site: http://www.americanheart.org/presenter.jhtml?identifier=1200013