HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 89/1/467S    most recent ajcn.2008.26717Dv1 Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lanza, I. R Articles by Nair, K S. Search for Related Content PubMed PubMed Citation Articles by Lanza, I. R Articles by Nair, K S. Agricola Articles by Lanza, I. R Articles by Nair, K S.

Muscle mitochondrial changes with aging and exercise^1,2,3,4

¹ From the Division of Endocrinology, Endocrinology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.

² Presented at the symposium "The Emerging Interplay among Muscle Mitochondrial Function, Nutrition, and Disease," held at Experimental Biology 2008, San Diego, CA, 5 April 2008.

³ Supported by NIH grants RO1 AG 09531, RO1 DK 41973, and UL1-RR-024150-01.

⁴ Reprints not available. Address correspondence to KS Nair, Mayo Clinic, 200 First Street SW, Joseph 5-194, Rochester, MN 55905. E-mail: nair.sree{at}mayo.edu.

Aging has been reported to be accompanied by reduced mitochondrial function and insulin sensitivity. Whether these deleterious effects result from chronological age or lifestyle-related factors such as adiposity and physical inactivity remains debatable. The beneficial effects of exercise on mitochondrial function and insulin sensitivity are well documented; however, it is unclear whether exercise can effectively prevent, reverse, or delay the onset of these age-related dysfunctions. Other investigators and we have found that endurance exercise enhances mitochondrial function across the life span, highlighting the beneficial role of exercise in combating age-related mitochondrial dysfunction. The literature is mixed concerning the ability of endurance exercise to normalize age-related insulin resistance; however, emerging evidence points to adiposity rather than age per se as a primary determinant of age-related declines in insulin sensitivity. Recent data from our laboratory also shed some light on the controversial relation between mitochondrial function and insulin sensitivity. Although some investigators purport a causal role of mitochondrial dysfunction in the etiology of insulin resistance, we provide evidence that the reverse may be true based on the fact that insulin stimulates mitochondrial function in healthy control subjects but not in patients with type 2 diabetes. Furthermore, we find that these 2 variables are completely dissociated in some populations, such as Asian Indians, who exhibit elevated mitochondrial capacity despite marked insulin resistance compared with European Americans. Our data not only point to regular endurance exercise as a viable strategy to delay the onset of age-related dysfunctions but they suggest that mitochondrial function and insulin resistance may be linked by additional factors such as physical activity.

This article has been cited by other articles:

				S. N Thornton and K. Hess Exercise, lactate, and mitochondrial function in aging and diabetes Am. J. Clinical Nutrition, May 1, 2009; 89(5): 1476 - 1476. [Full Text] [PDF]

				I. R Lanza and K S. Nair Reply to SN Thornton and K Hess Am. J. Clinical Nutrition, May 1, 2009; 89(5): 1476 - 1477. [Full Text] [PDF]

				K. R Short Introduction to symposium proceedings: the emerging interplay among muscle mitochondrial function, nutrition, and disease Am. J. Clinical Nutrition, January 1, 2009; 89(1): 453S - 454S. [Full Text] [PDF]

				G. P Holloway, A. Bonen, and L. L Spriet Regulation of skeletal muscle mitochondrial fatty acid metabolism in lean and obese individuals Am. J. Clinical Nutrition, January 1, 2009; 89(1): 455S - 462S. [Abstract] [Full Text] [PDF]

				J. O Holloszy Skeletal muscle "mitochondrial deficiency" does not mediate insulin resistance Am. J. Clinical Nutrition, January 1, 2009; 89(1): 463S - 466S. [Abstract] [Full Text] [PDF]