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).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
This programme consists of supervised, group-based sessions (2-3 per week, \~45 minutes each) combining concise theoretical instruction with guided practical execution of the snack-exercise protocol. Sessions are delivered by a qualified exercise professional and focus on teaching correct technique, safety, and progression of the prescribed short exercise bouts ("exercise snacks"). At the end of each session, participants receive an individualized home-based exercise prescription, tailored to their functional capacity and progression markers. Exercise intensity during supervised and home practice is monitored using the OMNI-BORG perceived exertion scale, progressing from light to moderate intensity, in accordance with World Health Organization recommendations.
A standardized brief educational counseling session delivered by trained research personnel during the baseline assessment. This session will provide foundational information on the benefits of physical activity for healthy aging and offer practical strategies for incorporating short "physical activity snacks" into daily routines. This ensures a consistent educational baseline for both study arms.
Fernão de Magalhães Health Center
Coimbra, Portugal
Recruitment Rate (Reach)
The percentage of eligible individuals who consent to participate in the study out of all individuals invited. This will be a measure of the reach and appeal of the intervention and study design.
Time frame: From the start of recruitment until the target sample size is reached (approximately 2 months).
Adherence to the "Snack Exercise" Program (Effectiveness)
The percentage of scheduled "snack exercise" sessions attended by participants in the intervention group. Adherence will be calculated as (number of sessions attended / total number of scheduled sessions) x 100. This measures the effectiveness of the program in engaging participants.
Time frame: Throughout the 12-week intervention period.
Program Implementation Fidelity (Implementation)
The degree to which the "snack exercise" program is delivered as intended by the study protocol. This will be assessed by a checklist monitoring staff adherence to the protocol, including session content, duration, and intensity monitoring procedures. It will be measured as a percentage of protocol items successfully delivered.
Time frame: Throughout the 12-week intervention period.
Participant Retention Rate
The percentage of enrolled participants who complete all study assessments at all time points (T0, T1, and T2). This measures the overall acceptability of the study procedures and the ability to retain participants over the full duration.
Time frame: From baseline (T0) to the final follow-up assessment (T2) at 18 weeks.
Intention to Continue Exercise (Maintenance)
Assessed via a self-report questionnaire administered at the final follow-up visit, evaluating participants' intention and confidence to continue with "snack exercise" or other forms of physical activity independently after the study concludes.
Time frame: At the final follow-up assessment (T2) at 18 weeks.
Multidimensional Lifestyle and Health Status
Evaluated using the Healthy Lifestyle Assessment Toolkit, a comprehensive instrument that assesses multiple domains including cardiometabolic health (blood pressure), well-being, nutrition, mental health, sleep quality, and self-perceived health status. The toolkit identify risks and guide interventions, using systems like traffic light scores (green/yellow/orange) for feedback and promoting behavior change for better health outcomes.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Daily Physical Activity Patterns
Objectively measured using a triaxial accelerometer (worn on the hip for 5-7 consecutive days). Participants will be instructed to wear the device during all waking hours, removing it only for water-based activities or sleeping. The accelerometers provided objective measures of daily movement patterns, including step count, time spent in different activity intensities, and sedentary behavior. This approach allow us to evaluate changes in physical activity levels throughout the intervention and to assess adherence.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Body Composition - Dual-Energy X-ray Absorptiometry (DEXA)
Assessed using Dual-Energy X-ray Absorptiometry (DEXA) to measure changes in fat mass, lean mass, and bone mineral density.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Anthropometrics - Height
Anthropometric measures including height - height in meters (m).
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Anthropometrics - Weight
Anthropometric measures including Weight - weight in kilograms (kg).
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Anthropometrics - Body Mass Index (BMI)
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Anthropometric measures including Body Mass Index (BMI) - weight in kilograms by height in meters squared (kg/m\^2).
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Anthropometrics - Waist circumference
Anthropometric measures including waist circumference will also be collected - waist circumference in cm.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Cardiorespiratory Fitness
Assessed using the One-Mile Walk Test (1,61 kilometers) for evaluation of cardiovascular fitness, to predict an individual's aerobic capacity, also known as maximal oxygen consumption (VO2 max). A slower time indicates lower cardiorespiratory fitness, and it's also a strong predictor of health outcomes.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Functional Fitness (muscular endurance)
A battery of tests will be used, including the 30-second chair stand test for muscular endurance. This measures lower body muscular endurance by counting how many times a person can stand up from a chair and sit back down in 30 seconds, using arms folded across the chest for support. Scores decline with age. A below average score (in seconds) indicates a risk for falls, being the cut off for each age group: 65-69: \< 12 (M); \< 11 (W) 70-74: \< 12 (M); \< 10 (W) 75-79: \< 11 (M); \< 10 (W) 80-84: \< 10 (M); \< 9 (W) 85-89: \< 8 (M); \< 8 (W) 90-94: \< 7 (M); \< 4 (W)
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Functional Fitness and Fall risk - Short Physical Performance Battery (SPPB)
A battery of tests will be used, including the Short Physical Performance Battery (SPPB) for functional capacity and fall risk. This is an objective test for older adults assessing lower-body function via 3 tasks: standing balance, usual gait speed (4m walk), and chair stands (5 reps, arms crossed). Scoring 0-12 (higher is better), predict disability, falls, hospitalization, and mortality, and is highly reliable for measuring physical capability in various settings.
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Fall Risk and Functional stability (force platform)
Assessment of limits of stability using a force platform for functional stability (Physiosensing® v.19002, Sensing Future, Coimbra, Portugal).
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).
Exercise Self-Efficacy (ESES)
Assessed using the Exercise Self-Efficacy Scale (ESES), a self-report measure to evaluate participants' confidence in their ability to engage in exercise. Participants answer on a 4-point rating scale, possible scoring range 10-40. A higher total score means greater exercise self-efficacy (stronger belief in one's ability to exercise).
Time frame: Assessed at baseline (T0), post-intervention (T1, 12 weeks), and follow-up (T2, 18 weeks).