Hyperglycemia

Hyperglycemia occurs in those who do not have controlled glucose levels, typically when levels exceed 250 mg/dl. This phenomenon occurs either when insulin is not present (such as in those who are not taking their insulin or in those who do not have an adequate dose) or when there is resistance to insulin, as we discussed in chapter 1. If either or both of these occur, the muscles are unable to fully utilize the glucose present in the blood. Hence, the body perceives that there are low blood glucose levels, and this starts a chain of events to induce production of glucose. This production of sugar occurs mainly in the liver. In addition, the body tries to obtain energy by breaking down body fat. These two processes cause even more elevated levels of glucose and production of harmful fat by-products called ketones. This leads to a drop in the blood's pH level; in other words, the blood becomes more acidic. The combination of these changes can lead to a dangerous and sometimes-fatal condition known as diabetic ketoacidosis, or DKA. This is a serious consequence of not controlling glucose levels. The best way to prevent DKA is to not start exercising until your glucose levels are safe enough for exercise-generally less than 200 mg/dl. Your doctor will advise you on what blood sugar levels are safe for exercise. However, if you have type 1 diabetes and a blood glucose greater than 250 mg/dl and ketones in your urine, or if you have type 2 diabetes and have a blood glucose greater than 300 mg/dl, you should absolutely not do any significant exercise until you consult your doctor.