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, PHD1,2
- 1Department of Health and Physical Activity, School of Education, University of Pittsburgh, Pittsburgh, Pennsylvania;
- 2Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
- Corresponding author: Bret H. Goodpaster, bgood{at}pitt.edu.
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 7 younger endurance-trained athletes, 12 older athletes, 11 younger normal-weight subjects, 10 older normal-weight subjects, 15 younger obese subjects, and 15 older obese subjects using a glucose clamp. The nonathletes were sedentary.
RESULTS Insulin sensitivity was not different in younger endurance-trained athletes versus older athletes, in younger normal-weight subjects versus older normal-weight subjects, or in younger obese subjects versus older obese subjects. 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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The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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- Received February 11, 2009.
- Accepted April 18, 2009.
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Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
- © 2009 by the American Diabetes Association.
