Enforced Reduction in Physical Activity and Recovery in Older Adults

Study Overview
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Brief Summary
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Apparently healthy and well-functioning community dwelling 70-80 year-olds will be recruited to the study. All subjects undergo pre-screening for suitability and a physicians examination, as well as 7-day habitual daily steps are measured to ascertain baseline physical activity. Half of the recruited subjects (n=40) will be randomized into the intervention group and half (n=40) randomized into the control group. The intervention group is then required to reduce their daily steps to <2000 for a 2-week period. Thereafter, the intervention group participates to a 4-week strength+endurance training rehabilitation program and no longer has restricted daily step count. The control group continues their normal habitual physical activity level throughout the 6-week study period.

Official Title
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Enforced Reduction in Physical Activity and Recovery in Older Adults

Conditions
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Muscle Degeneration, Body Weight Changes, Walking, Difficulty

Intervention / Treatment
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* Behavioral: Step-reduction/Exercise Rehab


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged 70-80 years, community-dwelling, able to walk 500 m without assistance or use of walking aid and regularly walking >5000 steps per day, MMSE >24, BMI 20-35 kg·m2 (i.e. not underweight or severely obese), no serious cardiovascular or musculoskeletal disease, no risk factors for deep-vein thrombosis (e.g. blood clotting disorder, obesity, bowel diseases, personal or family history of DVT etc.), non-smoker, provision of informed consent. Exclusion Criteria: Underlying diseases likely to limit lifespan and/or intervention safety. Contraindication for physical exercise or physical tests identified during physician's examination, unwilling/unable to track daily step counts using accelerometer, excessive and regular use of alcohol (more than 7 units per week for women and 14 for men) difficulty in communication due to severe vision or hearing problems unwilling to provide consent or accept randomization into either study group

Ages Eligible for Study
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Minimum Age: 70 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomized Controlled Trial, with 2 parallel groups
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention group<br>Two weeks of daily step reduction (limited to 2000 steps per day) followed by four weeks of supervised gym-based exercise rehabilitation (twice per week strength training and twice per week cycle endurance training) | Behavioral: Step-reduction/Exercise Rehab<br>* 2-week limited daily steps (<2000), and then 4 weeks of typical strength+endurance exercise for older adults<br>|
| No Intervention: Control group<br>Continued monitoring of habitual daily step count without structured intervention. Classic control. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lean leg mass | DXA-measured total lean mass of the legs | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Whole-body fat mass | DXA-measured total body fat mass | 6 weeks | 
| Maximum isometric leg extension force | Maximum strength of legs | 6 weeks | 
| Walking economy | Oxygen uptake while walking at 3 and 5 km.h-1 | 6 weeks | 
| Short Physical Performance Battery (SPPB) | Walking, balance and chair-rise tests | 6 weeks | 
| Blood pressure | Systolic and diastolic blood pressure during rest (sitting) | 6 weeks | 
| HOMA indices | Blood glucose and insulin concentration based calculations related to insulin resistance and beta-cell function | 6 weeks | 
| White blood cell respiration | Isolated white blood cell respiration as a marker for mitochondrial function | 6 weeks |