The classic oral glucose tolerance test measures blood glucose levels five times over a period of three hours. Some physicians simply get a baseline blood sample followed by a sample two hours after drinking the glucose solution. In a person without diabetes, the glucose levels rise and then fall quickly. In someone with diabetes, glucose levels rise higher than normal and fail to come back down as fast.
Exercise. A program of regular exercise gives anyone a sense of good health and well-being; for persons with diabetes it gives added benefits by helping to control blood glucose levels, promoting circulation to peripheral tissues, and strengthening the heart beat. In addition, there is evidence that exercise increases the number of insulin receptor sites on the surface of cells and thus facilitates the metabolism of glucose. Many specialists in diabetes consider exercise so important in the management of diabetes that they prescribe rather than suggest exercise.
Also striking are the differences in incidence between mainland Italy (8.4 cases per 100,000 population) and the Island of Sardinia (36.9 cases per 100,000 population). These variations strongly support the importance of environmental factors in the development of type 1 diabetes mellitus. Most countries report that incidence rates have at least doubled in the last 20 years. Incidence appears to increase with distance from the equator. 
Jump up ^ Cheng J, Zhang W, Zhang X, Han F, Li X, He X, Li Q, Chen J (May 2014). "Effect of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on all-cause mortality, cardiovascular deaths, and cardiovascular events in patients with diabetes mellitus: a meta-analysis". JAMA Internal Medicine. 174 (5): 773–85. doi:10.1001/jamainternmed.2014.348. PMID 24687000.
Type 2 diabetes, which is often diagnosed when a person has an A1C of at least 7 on two separate occasions, can lead to potentially serious issues, like neuropathy, or nerve damage; vision problems; an increased risk of heart disease; and other diabetes complications. A person’s A1C is the two- to three-month average of his or her blood sugar levels.