© 2004 by the American Diabetes Association, Inc.
Physical Activity/Exercise and DiabetesAmerican Diabetes Association
Abbreviations: CAN, cardiac autonomic neuropathy ECG, electrocardiogram FFA, free fatty acid PAD, peripheral arterial disease PDR, proliferative diabetic retinopathy PN, peripheral neuropathy
During physical activity, whole-body oxygen consumption may increase by as much as 20-fold, and even greater increases may occur in the working muscles. To meet its energy needs under these circumstances, skeletal muscle uses, at a greatly increased rate, its own stores of glycogen and triglycerides, as well as free fatty acids (FFAs) derived from the breakdown of adipose tissue triglycerides and glucose released from the liver. To preserve central nervous system function, blood glucose levels are remarkably well maintained during physical activity. Hypoglycemia during physical activity rarely occurs in nondiabetic individuals. The metabolic adjustments that preserve normoglycemia during physical activity are in large part hormonally mediated. A decrease in plasma insulin and the presence of glucagon appear to be necessary for the early increase in hepatic glucose production during physical activity, and during prolonged exercise, increases in plasma glucagon and catecholamines appear to play a key role. These hormonal adaptations are essentially lost in insulin-deficient patients with type 1 diabetes. As a consequence, when such individuals have too little insulin in their circulation due to inadequate therapy, an excessive release of counterinsulin hormones during physical activity may increase already high levels of glucose and ketone bodies and can even precipitate diabetic ketoacidosis. Conversely, the presence of high levels of insulin, due to exogenous insulin administration, can attenuate or even prevent the increased mobilization of glucose and other substrates induced by physical activity, and hypoglycemia may ensue. Similar concerns exist in patients with type 2 diabetes on insulin or sulfonylurea therapy; however, in general, hypoglycemia during physical activity tends to be less of a problem in this population. Indeed, in patients with type 2 diabetes, physical activity may improve insulin sensitivity and assist in diminishing elevated blood glucose levels into the normal range.
The purpose of this position statement is
Cardiovascular system Peripheral arterial disease Retinopathy Nephropathy Neuropathy: peripheral Neuropathy: autonomic
Glycemic control Prevention of cardiovascular disease Hyperlipidemia Hypertension Fibrinolysis Obesity Prevention of type 2 diabetes
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