Impaired Glucose Tolerance Glucose tolerance is said to be impaired when blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes.
Symptoms of diabetes are generally absent.
A person who has impaired glucose tolerance may improve, so that blood-sugar levels become normal, or may remain unchanged, with sugar levels between normal and high. People with impaired glucose tolerance are more likely to have high blood pressure and high cholesterol levels-conditions long implicated in coronary heart disease.