Blood glucose levels that are above or below desired ranges can have deleterious effects on personal safety, performance and well-being. Mild, moderate and severe hypoglycemia put an individual at risk for impaired decision-making, accidents, loss of consciousness, seizure, and death. Elevated glucose has immediate implications in terms of energy levels, appetite, athletic performance (strength, stamina, speed, flexibility), intellectual performance (creative skills, multi-tasking, memory), social skills, and risk for acute illness. 

Diabetic coma -- also known as hyperglycemic hyperosmolar non-ketotic syndrome -- is a serious complication that can happen to a person with type-2 diabetes who is ill or stressed. Diabetic coma occurs when the blood sugar gets too high and the body becomes severely dehydrated. This can lead to shock, coma, and death.

People who are especially at risk include those who are chronically ill or disabled.

The good news is that major long-term multi-center studies such as the DCCT (Diabetes Control and Complications Trial) and the UKPDS (United Kingdom Prospective Diabetes Study) have confirmed that tight blood sugar control greatly reduces the risk for diabetic complications. Overall, the risk of complications can be reduced by approximately 30% for every 1 percentage point reduction in the HbA1c (which equals approximately a 30 mg/dl reduction in average blood sugar over 3 months).