Eight Months of Cardiopulmonary-Test-Guided Concurrent Training in Older Adults from a Rural Chilean Commune: A Secondary Analysis of a Controlled Quasi-Experimental Programme Evaluation

We examine outcomes associated with a 32-week concurrent training programme delivered in 2016 to older adults from San Rafael, rural Chile, using archived records from a controlled, non-randomised study. The training group (TG; $n=34$) was prescribed three supervised 70-min sessions weekly, with aerobic intensity based on percentages of peak heart rate measured during baseline cardiopulmonary exercise testing (CPET); the control group (CG; $n=30$) continued usual activities. In the common-slope model adjusted for baseline outcome, age and sex, the month-8 difference in peak $\dot{V}$O${}_2$ favours TG by 11.5 mL·kg${}^{-1}·$min${}^{-1}$ (95% confidence interval [CI], 9.8–13.1). A significant group-by-baseline interaction ($p=0.002$) indicates variation across baseline fitness. Other findings include lower adipose mass, higher cognitive screening scores and improved functional performance. CG-restricted effort sensitivity analyses retain differences above 10 mL·kg${}^{-1}·$min${}^{-1}$, but do not verify comparable effort in TG follow-up tests. Four CPET assessments in TG versus two in CG may introduce differential familiarisation, and attendance records are unavailable. Within-group changes in walking distance correlate weakly with changes in peak $\dot{V}$O${}_2$. Non-random allocation, unblinded assessment, cognitive ceiling effects and incomplete effort and adherence data limit causal interpretation. The findings support further evaluation in a pragmatic randomised trial with standardised assessment and documented adherence.