Physical Inactivity and Obesity Underlie the Insulin Resistance of Aging
- Francesca Amati, MD1,
- John J. Dubé, PhD2,
- Paul M. Coen, PhD2,
- Maja Stefanovic-Racic, MD2,
- Frederico G.S. Toledo, MD2 and
- Bret H. Goodpaster, PhD (bgood{at}pitt.edu)1,2
- 1 Department of Health and Physical Activity, School of Education, University of Pittsburgh
- 2 Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh
Abstract
Objective: Age-associated insulin resistance may underlie the higher prevalence of type 2 diabetes in older adults. We examined a corollary hypothesis that obesity and level of chronic physical inactivity are the true causes for this ostensible effect of aging on insulin resistance.
Research Design and Methods: We compared insulin sensitivity in seven younger endurance-trained athletes (YA), 12 older athletes (OA), 11 younger normal weight (YN), 10 older normal weight (ON), 15 younger obese (YO) and 15 older obese (OO) subjects using a glucose clamp. The non-athletes were sedentary.
Results: Insulin sensitivity was not different in YA vs. OA, in YN vs. ON or in YO vs. OO. Regardless of age, athletes were more insulin sensitive than normal weight sedentary subjects, who in turn were more insulin sensitive than obese subjects.
Conclusions: Insulin resistance may not be characteristic of aging, but rather associated with obesity and physical inactivity.
Footnotes
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- Received February 11, 2009.
- Accepted April 18, 2009.
- Copyright © American Diabetes Association
