Effects Of Age And Conditioning Status On Rest And Exercise Cardiac Performance

National Institute On Aging

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Abstract

Multiple changes in cardiovascular (CV) reserve functions occurring over a lifetime limit the ability of older persons to maintain biological homeostasis as both CV and non-CV pathologies emerge. To determine CV reserve functions at entrance into study (EAge) and the rates at which these change over time in participants of the Baltimore Longitudinal Study of Aging (BLSA) who were free of clinical CV disease and ranged in age from 23 to 79. Design An initial and up to five serial radionuclide ventriculographs measurements over an average 10-year follow-up at seated rest and during upright cycle exercise to exhaustion of: cardiac output (CO), heart rate (HR), end diastolic and end systolic volumes (EDV and ESV), ejection fraction (EF). Longitudinal and cross-sectional data were analyzed using linear mixed-effects and multiple regression models. Results We published our first longitudinal paper on this data showing that progressive AV uncoupling occurred with aging and was more pronounced in women than men. While Ea change did not differ by sex, Elv increased at a slower rate in women than in men. AV uncoupling was inversely associated with EDV and SV rates of change and a directly associated with an increase in ESV rate of change. Additional studies are needed to explore the functional consequences of AV uncoupling in healthy individuals with respect to the emergence of age-associated clinical cardiovascular diseases, such as heart failure with preserved ejection fraction. Work in progress on the rate at which peak CO, the most important cardiac reserve function, declines over time is dominated by the rates and direction of change in EDV and SV which differ among subjects. The within-person variability in changes that occur over time following EAge in most CV functions, however, is about 50% less than that measured between the same individuals at EAge. This suggests that relatively less time variant factors, eg. genetic, lifestyle, or environment, have a greater influence on CV reserve functions than do time-dependent changes (Aging). The impact of genetics, lifestyle, environment, and aging and interactions among these factors over time on CV reserve must be accounted for with respect to developing ideal CV disease prevention, detection, and management strategies for older patients.