Genetic, Physiologic and Behavioral Predictors of Cardiorespiratory Fitness in Specialized Military Men
Journal Article - Embargoed Full-Text,01 Jul 2015,
NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA SAN DIEGO United States
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Cardiorespiratory fitness CRF is a crucial performance requirement of specialized military occupations. Age and physical activity PA are established predictors of CRF, but it is not clear how these predictors combine with each other, andor with genetic predisposition. The goal of this study was to derive inclusive explanatory models of CRF in U.S. Navy Explosive Ordnance Disposal EOD men, synthesizing conventional e.g., age, body composition and physical activity and novel influences e.g., genetic variance. Forty male, active-duty EOD operators completed a graded exercise test GXT to assess maximal oxygen consumption VO2max and ventilatory threshold VT using the Bruce protocol. Aerobic performance was further quantified via time of test termination and time at which VT was achieved. Body composition was determined via dual x-ray absorptiometry, and physical activity was assessed by self-report. Genetic variants underlying human stress systems 5HTTLPR, BclI,2CG, and COMT were assayed. In univariate regression models, age, body composition, physical activity, and 5HTTLPR consistently predicted CRF andor aerobic performance R2 range .07 to .55. Multivariate regression models routinely outperformed the univariate models, explaining 36-62 percent of variance. This study signifies a shift toward inclusive explanatory models of CRF and aerobic performance, accounting for combined roles of genetic, physiologic, and behavioral influences. The findings have implications for assessment, selection, and training of specialized military members and may also impact mission success and survivability.
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