Short-Term Exercise, β-Cell Function, and Insulin Resistance in Older People with Impaired Glucose Tolerance
Abstract Number: 1007-P
Authors: ANNETTE M. CHANG, CATHIE J. BLOEM, MARLA J. SMITH, NEIL B. ALEXANDER, JEFFREY B. HALTER.
Institutions: Ann Arbor, MI.
Results: There is a high prevalence of diabetes and impaired glucose tolerance (IGT) in the older population. Normal aging is associated with insulin resistance and impaired insulin secretion, with greater defects in people with IGT. 7 days of exercise has been found to increase insulin sensitivity without changes in body weight/composition or VO2max. But, previous studies have not examined older people with IGT or β-cell function. We assessed the effects of 7 days of aerobic exercise in 8 sedentary older people with IGT. Screening included oral glucose tolerance test, stress/VO2 test, and DEXA scan.
Participant CharacteristicsMean±SDFrequently-sampled IV glucose tolerance test (FSIGT) was performed at baseline and 15-20 hrs post 7th exercise session. Insulin sensitivity (SI), IV glucose tolerance (Kg), acute insulin response to glucose (AIRg), disposition index (DI, AIRg x SI) or β-cell function in relation to insulin resistance were calculated. The change in parameters post-pre exercise was analyzed by Wilcoxan signed rank test.
|Body fat (%)||41±8|
|Fasting glucose (mg/dl)||107±8|
|2-hr OGTT glucose||164±20|
|Hemoglobin A1c (%)||5.7±0.1|
Metabolic Parameters Pre and Post 7-day ExerciseMean±SEExercise was well-tolerated. Body weight, fasting glucose/insulin, and Kg were unchanged with exercise. SI increased by 80%, AIRg decreased by 21%, and DI was not significantly changed. Thus, short-term exercise resulted in markedly improved SI , and adaptation of β-cell function to improved insulin resistance in older people with IGT.
|Fasting glucose (mg/dl)||103±4||106±4||0.6|
|Fasting insulin (μu/ml)||15±1||15±1||0.9|
|DI (AIRg x SI)||64±21||79±17||0.3|