Aerobic reserve and physical functional performance in older adults

Background: older adults can be limited in their performance of daily tasks due to an inadequate aerobic capacity. Aerobic capacity below minimum physiological thresholds required to maintain independence leaves older adults with little, or no, aerobic reserve. Objective: the aim of this study was to measure functional performance and aerobic reserve in older adults during the serial performance of daily tasks. Subjects: twenty-nine (n = 29) men and women (n = 23females) 70-92 years of age participated in this study. Methods: performance based physical function was assessed using the Continuous-Scale Physical Functional Performance test (CS-PFP). A Cosmed K4b(2)(TM). portable metabolic system was used to measure VO2PEAK and oxygen uptake during the serial performance of a battery of daily tasks (VO2PFP). Aerobic reserve was calculated as the difference between VO2PEAK and VO2PFP. Results: the correlation coefficient between aerobic reserve and functional performance was r = 0.50(P = 0.006). Participants utilized 32.2 +/- 8.1%, 42.7 +/- 10.8%, and 50.3 +/- 12.3% of VO2PEAK for the low, moderate, and high workloads of the CS-PFP, respectively. Conclusions: light housework and carrying groceries require 40 to 50% of peak oxygen consumption. This information can be used by clinicians and health professionals working with older adults as a guide to how much aerobic fitness is needed to perform ADLs and maintain independence. These can then be used as guides for assessment and for setting training goals in older adults.