Relationship between VO_2peak, VO₂ Recovery Kinetics, and Muscle Function in Older Adults

Abstract

<b><i>Introduction:</i></b> The efficiency of the cardiovascular system to recover following an exercise bout is measured by oxygen (VO₂) recovery kinetics. In older adults with a chronic disease, a higher aerobic capacity (VO_2peak) and faster VO₂ recovery kinetics are associated with higher muscle strength and physical capacity. Yet, this relationship in healthy older adults remains unclear. The aim of this cross-sectional study was to determine whether a higher VO_2peak and faster VO₂ recovery kinetics are associated with higher muscle strength and physical performance in healthy community-dwelling older adults. <b><i>Methods:</i></b> Thirty-five healthy older adults (female 25/male 10, mean age 73 ± 6 years) performed a graded exercise test on a cycle ergometer. VO_2peak and VO₂ recovery kinetics were assessed through gas exchange analysis. Muscle strength was determined by maximal leg (one-repetition maximum on leg press; 1RM) and grip strength, and physical performance was determined by the physical performance test (PPT) which assessed gait speed, stair ascent and descent, and timed up-and-go. <b><i>Results:</i></b> Higher VO_2peak was associated with stronger leg (<i>r</i> = 0.59, <i>p &lt;</i> 0.001) and grip strength (<i>r =</i> 0.39, <i>p &lt;</i> 0.03), but no relationship to PPT (<i>p &gt;</i> 0.05)<i>.</i> There was also no relationship between VO₂ recovery kinetics and leg and grip strength or PPT (<i>p &gt;</i> 0.05). <b><i>Conclusion:</i></b> In healthy community-dwelling older adults, VO_2peak, but not VO₂ recovery kinetics, is associated with muscle strength. This suggests that muscle strength may be an important factor related to aerobic capacity that could assist in identifying older adults who should be prioritized for resistance training.