Proceedings of The Physiological Society

Ageing and Degeneration (Edinburgh, UK) (2015) Proc Physiol Soc 33, PC30

Poster Communications

Assessing exercise capacity in older adults using a self-paced 6-minute stepper test (6-MST)

S. Jones1, T. Tillin1, N. Chaturvedi1, A. D. Hughes1

1. Institute for Cardiovascular Science, University College London, London, United Kingdom.

BackgroundExercise capacity is an important indicator of physical function in the aging population. Testing protocols are often ambulatory and require a long corridor (>30m). These protocols do not easily facilitate measurements of blood pressure or cardio-respiratory effort. Many studies also report poor acceptance from older adults.We assessed the feasibility of a 6-minute step test (6MST) for assessing exercise capacity in a tri-ethnic cohort of older adults. Test acceptability, sensitivity, reproducibility and agreement with a previously verified testing protocol were determined.MethodParticipants (n=181; 116=male, mean age 71±6years) were invited to undertake a 6MST on a stepper (Homcom, miniStepper) with hand-rail support provided. Number of steps, time stepping and perceived exertion were recorded, cardiorespiratory effort was monitored by portable gas analysis (K4b2,Cosmed). A sub-set of participants completed a 6-minute walk test (6MWT) and a second 6MST.Variables for all participants were compared by gender. Number of steps, perceived exertion and highest VO2 were compared between the first and second 6MST and between the first 6MST and the 6MWT. Data are means±SD or means±SD of differences (Δ) (6MST(2) - 6MST(1) or 6MST(1)-6MWT); a Student's t-test was used for comparisons.ResultsAll participants agreed to undertake the 6-MST . 164 (91%) participants agreed to wear a mask to monitor cardiorespiratory effort and 121 (67%) completed 6 minutes of stepping. Overall men achieved a higher VO2 than women (16.82±3.87 versus 14.20±3.26ml/l/kg, p<0.001). 10 participants completed a repeat 6MST and a 6MWT. On average participants completed 53 steps more in the second 6MST versus the first (p=0.02). There was no significant difference in perceived exertion (Δ=0.6±1.4, p=0.2), highest VO2 (Δ=93.2 ±218ml/min, p=0.2) or heart rate (Δ=3±13bpm, p=0.5) between first and second step tests. Perceived exertion was similar in the first 6MST and the 6MWT (Δ=0.95±2.36, p=0.2) with no significant difference in highest VO2 (Δ=73±401ml/min, p=0.6) or heart rate increase (Δ=9±21bpm, p=0.2) during the first 6MST and the 6MWT.ConclusionThe 6-MST is a feasible and acceptable method for assessing exercise capacity in older adults. It is sensitive to expected gender differences in peak VO2. The test is reproducible in terms of cardiorespiratory effort and perceived exertion but there is a ‘learning effect' of ~15% improvement in steps achieved during the second step test. Measures of cardiorespiratory effort and perceived exertion showed acceptable agreement with a 6MWT but unlike a 6MWT, the 6MST permits continual BP measurements.

Where applicable, experiments conform with Society ethical requirements