This study will explore a new way for older adults to become more physically active. As people get older, it's common to gain weight and lose muscle strength. This combination can make it harder to do daily activities, increase the risk of falls, and impact overall quality of life. While we know that regular exercise is very beneficial, many older adults find it difficult to stick to traditional exercise programs due to lack of time, motivation, or energy.

This research project, called COMPASS 65+, will test an innovative approach called "snack exercise." Instead of one long workout, "snack exercise" involves doing several short bouts of activity, a few minutes at a time, throughout the day. The main idea is that these short, frequent bouts of activity might be easier to fit into a daily routine and less tiring than longer exercise sessions.

The purpose of this study is to see if a "snack exercise" program is a feasible and enjoyable way for adults aged 65 and over, who are overweight or obese, to improve their health. The study will be conducted in two main parts. First, the research team will talk with older adults to understand what helps or hinders them from being active to co-design the program. Second, volunteers will be randomly assigned to either a "snack exercise" group or a control group.

Participants in the "snack exercise" group will attend sessions that combine theory and practice to learn how to perform these exercises and will receive individualized prescriptions to perform the "snacks" (short bouts) at home. The control group will receive a brief educational counselling session on physical activity. Participants' health status, body composition, and physical fitness will be assessed at baseline, after the 12 weeks intervention, and again 6 weeks post-intervention to evaluate the maintenance of any improvements. These outcomes will help determine whether short bouts of 'exercise snacking' constitute a feasible and effective strategy to promote functional capacity, metabolic health, and long-term adherence to physical activity.

Study Rationale and Background The intersection of an aging population and the obesity epidemic poses a significant public health challenge, particularly for adults aged 65 and older. This combination often leads to sarcopenic obesity, a condition characterized by excess body fat and low muscle mass and strength, which substantially increases the risk of falls, frailty, functional decline, and loss of independence. While physical activity is a proven non-pharmacological intervention to counteract these declines, adherence to traditional, structured exercise programs remains low among older adults. Barriers such as a perceived lack of time, low motivation, and fatigue create a gap between the known benefits of exercise and its practical implementation in real-world community settings.

This study, COMPASS 65+, proposes to evaluate an innovative exercise modality known as "snack exercise." This approach involves short, frequent bouts of physical activity performed throughout the day, designed to be more accessible and less burdensome than conventional exercise routines. The primary aim of this project is to assess the feasibility, acceptability, and preliminary effects of a community-based "snack exercise" program, co-designed with input from the target population, for overweight and obese older adults. The findings are intended to provide the necessary evidence to design a future, definitive large-scale randomized controlled trial (RCT).

Study Design

The research plan is structured in two sequential phases:

1. Phase 1: Exploratory Mixed-Methods Study This initial phase is designed to inform the development of the intervention. It involves a mixed-methods approach to identify barriers, facilitators, and preferences related to physical activity among the target population.

   • Quantitative Component: A cross-sectional survey will be administered to a convenience sample of 370 adults aged 65 or older with a Body Mass Index (BMI) of 25 kg/m² or greater. The survey will include validated instruments such as the Exercise Benefits/Barriers Scale (EBBS) and the Multimorbidity Treatment Burden Questionnaire (MTBQ).
   • Qualitative Component: Focus groups will be conducted with a randomly selected subset of the target population to explore user preferences for program design.The data will be integrated to co-design a "snack exercise" intervention that is evidence-based and tailored to user needs.

2. Phase 2: Feasibility Randomized Controlled Trial (RCT) A two-arm, parallel-group feasibility RCT will be conducted to test the co-designed intervention.

   • Participants: A target of 60 participants will be recruited from primary care settings. Inclusion criteria include adults aged ≥ 65 years with a BMI ≥ 25 kg/m². Exclusion criteria include significant cognitive deficits, contraindications to exercise (assessed via PAR-Q+), major cardiovascular events within the last 3 months, unstable chronic disease, or severe mobility impairment.
   • Randomization: Participants will be randomly allocated (1:1) to either the intervention group or the control group.
   • Timeline: The intervention lasts 12 weeks, followed by a 6-week post-intervention "washout" period. Assessments occur at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
   • Intervention Groups Active Comparator (Control Group): Participants will receive a single, standardized Brief Educational Counselling Session (60 minutes) at baseline (T0). Delivered by trained research personnel, this session provides foundational information on the benefits of physical activity for healthy aging and offers practical strategies for incorporating short "physical activity snacks" into daily routines. This ensures a consistent educational baseline.

Experimental Group ("Snack Exercise"): Participants will receive the standardized Brief Educational Counselling Session at baseline, followed by the Structured Community-based Physical Activity Snack Intervention. This program consists of group-based, theoretico-practical sessions held 2-3 times per week, each lasting approximately 45 minutes. Sessions are guided by a physical exercise professional and focus on explaining and practicing the prescribed snack exercises. Crucially, at the end of each session, participants are provided with an individualized physical prescription to perform at home. Exercise intensity is monitored using perceived exertion scales (BORG-OMNI), progressing from light to moderate intensity per WHO recommendations.

Study Procedures and Outcome Measures Protocol & Ethics: The study adheres to SPIRIT guidelines and the Declaration of Helsinki, with Ethics Committee approval and written informed consent required.

Outcomes & Data Collection: Comprehensive assessments are conducted at T0, T1, and T2 using validated instruments and objective tools:

• Body Composition & Anthropometrics: Dual-Energy X-ray Absorptiometry (DEXA) for fat/lean mass and bone density; Height, Weight, BMI (kg/m^2), and Waist Circumference.
• Cardiorespiratory Fitness: One-Mile Walk Test to predict aerobic capacity (VO2 max).
• Functional Fitness & Fall Risk: The Short Physical Performance Battery (SPPB) (assessing balance, gait speed, and chair stands) and the 30-second Chair Stand Test (muscular endurance).
• Stability: Limits of stability assessed via a force platform (Physiosensing®).
• Daily Physical Activity: Objectively measured using a Fitband worn for five consecutive days (step count, active minutes).
• Psychosocial & Health Status: Exercise Self-Efficacy Scale (ESES).
• Multidimensional Lifestyle and Health Status (assessed via the Healthy Lifestyle Assessment Toolkit, covering cardiometabolic health, well-being, nutrition, mental health, and sleep).

Statistical Analysis Plan Primary Analysis (Feasibility): Descriptive analysis of recruitment, adherence, retention, and protocol fidelity based on the RE-AIM framework.

Secondary Analysis (Preliminary Effects): Repeated measures ANOVA or mixed models will be used to assess changes over time (T0, T1, T2) and between groups (p< 0.05). The goal is to estimate effect sizes to power a future definitive trial.

Data Management: All analyses will be conducted using SPSS (Version 29), with appropriate handling of missing data (e.g., multiple imputation).

Inclusion Criteria:

• adults aged ≥65 years with a BMI ≥25 kg/m².

Exclusion Criteria:

• significant cognitive deficits,
• contraindications to exercise (assessed via PAR-Q+),
• major cardiovascular events within the last 3 months,
• unstable chronic disease,
• severe mobility impairment.

A plan for sharing individual participant data with external researchers has not been established at this stage for several reasons. Primarily, this is a feasibility study with a small sample size, designed to inform the design of a future, larger trial rather than to produce generalizable findings. Due to the small cohort and specific regional recruitment, there is a potential risk of deductive disclosure of participant identity, even with de-identified data. Furthermore, the informed consent obtained from participants does not include a specific clause for sharing their individual data beyond the core research team for secondary research purposes. Therefore, to uphold ethical commitments to participant confidentiality, IPD will not be made available at the conclusion of this study.