Effects of a Smart Circuit Exercise Program on Health Outcomes in Community-Dwelling Older Adults

This study was conducted in collaboration with a community-based retirement facility to evaluate the clinical effectiveness of a smart, technology-assisted circuit exercise intervention for community-dwelling older adults. Traditional exercise prescriptions for older adults often lack real-time monitoring of individual physiological responses, which can increase the risk associated with exercise participation. This program integrated real-time physiological monitoring (including heart rate reserve, HRR) to guide individualized exercise intensity within a moderate-intensity range (50%-60% HRR).

The study was conducted in two stages with different allocation designs:

Stage 1 (Randomized Controlled Design): Participants were randomly assigned to either an intervention group or a control group. The intervention group received the smart circuit exercise program, while the control group did not receive the exercise intervention and underwent pre- and post-assessment only. This stage allowed for between-group comparison of intervention effects.

Stage 2 (Single-Group Extension): Following the completion and analysis of Stage 1, which demonstrated the safety and preliminary effectiveness of the smart circuit exercise program, the facility extended the program to a broader group of community residents as part of a real-world implementation and scale-up initiative, in order to evaluate the program's effectiveness under routine practice conditions and to provide equitable access to the intervention across the community. A concurrent control group was not maintained during this stage, consistent with its focus on real-world effectiveness evaluation rather than efficacy comparison.

Participants in both stages received circuit-based exercise training three times per week (24 sessions total across approximately 8 weeks), with intensity controlled at 50%-60% heart rate reserve (HRR).

Outcome measures assessed before and after the intervention period included: body composition (including skeletal muscle mass, body fat mass, and body fat percentage), blood pressure, functional fitness (lower limb muscle strength and dynamic balance), clinical blood biochemistry indicators (including HbA1c), depressive symptoms (CESD-10), and sleep quality (Pittsburgh Sleep Quality Index, PSQI).

Statistical analyses included two-way mixed-design analysis of variance and paired-samples t-tests, with statistical significance set at alpha = .05. Stage 1 data were analyzed as a between-group comparison. Stage 2 data were analyzed independently as a within-group pre-post comparison and were not statistically compared to the Stage 1 control group, given the non-concurrent recruitment timing between stages.

Note: This trial is being registered retrospectively. The study was conducted and closed under IRB approval prior to the decision to pursue publication in international peer-reviewed journals, at which point trial registration was completed.

Inclusion criteria

• Age 65 to 85 years, community-dwelling
• Able to walk independently, without assistance
• Able to understand study procedures in Mandarin or Taiwanese and voluntarily provide informed consent
• Willing to undergo health examinations and testing, and to provide historical health examination records
• Completed a health status questionnaire covering medical history, medication use, and comorbidities
• Physical Activity Readiness Questionnaire Plus (PAR-Q+) results indicating suitability for exercise training (or written physician clearance obtained if any positive response)
• Completed the International Physical Activity Questionnaire (IPAQ), with results not meeting the criterion for regular exercise within the past 6 months (i.e., fewer than 2 sessions/week or less than 30 minutes/session of moderate-intensity aerobic exercise)

Exclusion criteria

• Cognitive impairment or dementia precluding understanding of study procedures or compliance with test instructions
• Lower-extremity fracture, joint surgery, or joint replacement within the past 3 months precluding safe completion of sit-to-stand or walking tasks
• Severe joint pain precluding safe completion of baseline test movements, as assessed by study personnel
• Unexplained syncope or fall history within the past 3 months, or safety concerns as assessed by study personnel
• Acute illness (e.g., fever, acute infection)
• Cardiac pacemaker or incompatible metal implants affecting bioelectrical impedance analysis (BIA) measurement safety
• Meeting the criterion for regular exercise within the past 6 months per the International Physical Activity Questionnaire (IPAQ) (≥2 sessions/week, ≥30 minutes/session of moderate-intensity aerobic exercise)
• Physical Activity Readiness Questionnaire Plus (PAR-Q+) screening results indicating unsuitability for exercise training, without written physician clearance
• Unstable cardiovascular disease, including unstable angina, uncontrolled atrial or ventricular arrhythmia, uncontrolled resting sinus tachycardia (>120 beats/min), decompensated congestive heart failure, third-degree atrioventricular block without a pacemaker, acute pericarditis or myocarditis, or recent thrombosis/thrombophlebitis
• Uncontrolled diabetes (HbA1c > 9%, resting blood glucose > 300 mg/dL, or > 250 mg/dL with ketosis) or poorly controlled hypertension (systolic blood pressure > 180 mmHg or diastolic blood pressure > 100 mmHg)
• Use of medications that may interfere with muscle metabolism (e.g., high-dose corticosteroids, immunosuppressants)
• Symptomatic orthostatic hypotension (blood pressure drop > 20 mmHg)
• Resting ST-segment depression > 2 mm
• Severe neurological or musculoskeletal disease precluding safe performance of study procedures, as assessed by study personnel
• Currently participating in another clinical trial involving an exercise intervention
• Severe anemia, acute infectious disease, or other physiological conditions deemed unsuitable for exercise training by the investigator