title: The influence of age and cardiorespiratory fitness on kinetics of oxygen uptake.
abstract: The purpose of this study was to determine the influences of ageing and cardiorespiratory fitness on kinetics of VO2 during the transition to exercise of moderate intensity. Subjects performed three transitions to and from a 6-minute square wave constant load, at an intensity corresponding to 90% of ventilatory threshold (VET), to determine VO2 kinetics. The young group had a significantly faster time constant of VO2 (tau VO2). Tau VO2 was significantly correlated with VO2max for both young and old groups; however, the slope of the tau VO2--VO2max regression equation was steeper for the old group, indicating that fit older subjects had VO2 kinetics that approached those of fit young. A multiple linear regression indicated that relative fitness was the strongest significant predictor of tau VO2, followed by sex and age. Although VO2 kinetics are definitely slowed with age, relative levels of cardiorespiratory fitness also have a great influence on the dynamic response of VO2.
authors.affiliation: Centre for Activity and Ageing, University of Western Ontario, London.
authors.forename: P D
authors.initials: PD
authors.lastname: Chilibeck
authors.forename: D H
authors.initials: DH
authors.lastname: Paterson
authors.forename: R J
authors.initials: RJ
authors.lastname: Petrella
authors.forename: D A
authors.initials: DA
authors.lastname: Cunningham
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D002245:Carbon Dioxide / Q000378:metabolism; D005080:Exercise Test; D005260:Female; D005544:Forecasting; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007700:Kinetics; D016014:Linear Models; D008168:Lung / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012044:Regression Analysis; D012119:Respiration / Q000502:physiology; D012737:Sex Factors; D013990:Tidal Volume
chemical_list: D002245:Carbon Dioxide