The role of medium-intensity training in promoting functional independence and cognitive function in older adults: a randomized controlled trial

Aging is associated with declines in physical and cognitive capacities, negatively affecting functional independence and quality of life. While physical exercise is recommended for healthy aging, uncertainty remains regarding the optimal training intensity for simultaneously supporting physical and cognitive outcomes. This study evaluated the effects of medium-intensity training (MIT) on functional independence and cognitive function in older adults. A six-month assessor-blinded randomized controlled trial was conducted with 72 community-dwelling older adults aged 60–70 years. Participants were randomly assigned using a computer-generated sequence to either the MIT group ( n = 36) or control group ( n = 36). The MIT program was performed three times per week at moderate intensity, prescribed using individualized heart-rate reserve targets and supported by perceived exertion monitoring. Functional independence and cognitive function were measured using the Katz Index of Independence in Activities of Daily Living (ADL) and Mini-Mental State Examination (MMSE), respectively. Data were analyzed using paired and independent t-tests for within- and between-group comparisons, and two-way repeated measures ANOVA to evaluate Time × Group interaction effects. Assumptions of normality were verified (Shapiro–Wilk test, p > 0.05). Significance was set at p < 0.05, with effect sizes interpreted cautiously in light of outcome variability and the pre–post randomized design. Baseline characteristics did not differ meaningfully between groups. Following MIT, the exercise group significantly improved in functional independence (Katz Index: 4.31 ± 0.46 to 5.33 ± 0.77; p = 0.006) and cognitive function (MMSE: 18.77 ± 2.64 to 22.25 ± 4.38; p = 0.001). The control group showed no significant changes in Katz Index (4.53 ± 0.50 to 4.24 ± 0.82; p = 0.731) or MMSE (18.31 ± 2.01 to 19.07 ± 0.81; p = 0.434). Two-way repeated measures ANOVA confirmed significant Time × Group interactions for both outcomes, suggesting greater improvements in the MIT group than in the control group. A six-month medium-intensity training program was associated with improvements in functional independence and cognitive function among community-dwelling older adults. These findings support MIT as a feasible, low-cost exercise approach for community-based healthy aging programs. Future studies with larger samples, objective intensity monitoring, systematic adherence tracking, adverse-event reporting, and long-term follow-up are warranted. Trial registration : This trial was retrospectively registered in the Thai Clinical Trials Registry (TCTR20250613003) on 13 June 2025.