In this proposal we plan to combine community-, clinical-, and laboratory-based measures to understand more clearly the role of specific cellular, hormonal, anthropometric, and metabolic adaptations that maintain function in successful aging. To accomplish these goals, we plan to study postmenopausal women with state-of-the-art clinical, laboratory, and innovative and practical training techniques specific to mechanisms and precursors of type 2 diabetes. The overall purpose of the proposed study is to determine the impact of aerobic exercise on improvements in glucose disposal in older women and to identify key factors in this relationship. With this proposal we plan: 1) to establish cross-sectional differences in levels of several hormone- and lipid-related mechanisms and modulators of insulin resistance (e.g., muscle lipoprotein lipase (LPL) mRNA and protein content, cortisol response to a physical challenge, attenuated suppression of insulin-stimulated hepatic glucose production (HGP) and plasma concentrations of free fatty acids) in older women of normal body weight, but with and without excess visceral-to subcutaneous abdominal adiposity; 2) to determine the effects of 9 months of aerobic exercise training of either higher- or moderate-intensity (but equivalent caloric output) on the mini-trampoline on these hormone- and lipid-related variables and consequent insulin-stimulated whole-body glucose disposal; and 3) to determine whether the degree of adaptation with training varies by training intensity and/or size of the visceral fat depot. To our knowledge, this has not been demonstrated in any older population using these techniques. By determining whether the aging-related changes in these study variables and consequent deficit in glucose regulation are altered by exercise, we can provide insight into the factors associated with compromised function in older age and the extent to which adaptation occurs. Moreover, this information can then be used to design safe and effective community-based exercise programs for older people that focus on the maintenance of glucose regulation and overall function in aging.
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