Investigating Fitness Interventions in the Elderly (INFINITE)
Summary
Aging is associated with declines in aerobic capacity, exercise tolerance, and functional endurance that lead to physical disability and loss of independence. Furthermore, the existing high prevalence of obesity in the elderly is greatly exacerbating these aging-related declines in function. To date, regular exercise is the only known therapy to consistently improve aerobic function, and perhaps delay the onset of disability. Although aerobic exercise training does benefit both aerobic capacity and endurance even in obese persons, some data show that the maximal efficacy of exercise for improving aerobic function is blunted by obesity. In addition, our preliminary data show a potential dose-response benefit of concomitant fat loss on exercise-induced improvements in aerobic function. Thus, combining an exercise intervention with caloric restriction resulting in fat loss may be more efficacious for improving aerobic function than exercise alone in obese elderly, a population at high risk for disability. The purpose of this study is to determine whether the amount of fat loss (achieved through controlled underfeeding) affects the magnitude of improvement in aerobic function (maximal aerobic capacity and endurance) in response to a standardized exercise training stimulus that follows current recommendations for older persons.
Description
Design Overview:
Phase 1 involves recruitment and screening followed by baseline research testing (Phase 2). Next, subjects will be randomly assigned to one of three 5-month treatments (Phase 3): exercise and high-caloric restriction diet, exercise and low-caloric restriction diet, or exercise only. Subjects will complete follow-up testing after their 5 month intervention.
Interventions:
Dietary interventions: All participants will be randomly assigned to an exercise intervention with either no dietary intervention (EX Only), or 1 of 2 hypocaloric controlled diets: 1) -250 kcal/day deficit for low fat loss (EX+LOW CR) or 2) -600 kcal/day deficit for high fat loss (EX+HIGH CR) for 20 weeks.
All meals are prepared individually after participants choose from a hypocaloric menu designed by the RD to provide a balanced, healthy diet. The calorie level assigned for each person will provide him/her with an absolute daily caloric deficit consistent with their group assignment (-600 or -250 kcals/day). Individual calorie levels will be prescribed to provide calorie levels to the nearest 50 kcals (e.g., 1100 kcal, 1150 kcal, 1200 kcal, etc.). They are educated by the GCRC RDs and provided menus to guide their food purchasing and preparation of daily breakfast meals that are consistent with the prescribed calorie level. They are asked to consume only the food that is given to them or that is approved from the breakfast menu. All participants will pick up their food 3 times/wk during the intervention, and are asked to keep a log of everything they eat or drink.
Exercise intervention: The exercise will take place in an exercise facility at the Geriatric Research Center on the campus of the Wake Forest University/Baptist Medical Center. Two study personnel, including at least one trained technician, will supervise all exercise sessions. Emergency equipment will be kept on site during exercise sessions. Blood pressure and heart rate (HR) will be measured before each exercise session and subjects will warm-up by walking for 3-5 min at a slow pace and will then walk at an intensity of 65-70% of heart rate reserve (HRR, assessed during the VO2max test). The duration of walking exercise will progress from 15-20 mins at 50% HRR the 1st week to 30 mins at 65-70% HRR by the end of the 6th week and thereafter. Each walking session will end with a 3-5 min cool-down followed by 5 min of large muscle flexibility exercise.
Study Design
Allocation: Randomized, Control: Active Control, Intervention Model: Parallel Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Treatment
Conditions
Obesity
Intervention
Exercise Only, Exercise + Diet, Exercise + Diet
Location
Wake Forest University
Winston Salem
North Carolina
United States
Status
Recruiting
Source
Wake Forest University
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT01048736
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Exercise Tolerance
The exercise capacity of an individual as measured by endurance (maximal exercise duration and/or maximal attained work load) during an EXERCISE TEST.
Exercise Test
Controlled physical activity, more strenuous than at rest, which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used. The intensity of exercise is often graded, using criteria such as rate of work done, oxygen consumption, and heart rate.
Bariatrics
Activities related to WEIGHT REDUCTION in patients with OBESITY. Treatment methods include DIET; EXERCISE; BEHAVIOR MODIFICATION; medications; and BARIATRIC SURGERY.
Asthma, Exercise-induced
Asthma attacks following a period of exercise. Usually the induced attack is short-lived and regresses spontaneously. The magnitude of postexertional airway obstruction is strongly influenced by the environment in which exercise is performed (i.e. inhalation of cold air during physical exertion markedly augments the severity of the airway obstruction; conversely, warm humid air blunts or abolishes it).
Echocardiography, Stress
A method of recording heart motion and internal structures by combining ultrasonic imaging with exercise testing (EXERCISE TEST) or pharmacologic stress.
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PubMed Articles
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