Investigating Fitness Interventions in the Elderly (INFINITE)
| Status: | Completed |
|---|---|
| Conditions: | Obesity Weight Loss |
| Therapuetic Areas: | Endocrinology |
| Healthy: | No |
| Age Range: | 65 - 80 |
| Updated: | 8/3/2018 |
| Start Date: | October 2009 |
| End Date: | September 2014 |
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.
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.
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.
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.
Inclusion Criteria:
- BMI=30-34.9 kg/m2
- Sedentary for past 6 months (<30 min, 3 d/wk of exercise, including walking)
- Normal cognitive function (MMSE >24)
- No contraindications for participation in weight loss or exercise (e.g., severe
arthritis or musculoskeletal disorders)
- Able to provide own transportation to study visits and intervention
- No drug abuse or excessive alcohol use (> 7 drinks/week)
- Not dependent on a cane or walker
Exclusion Criteria:
- Weight loss or gain (±5%) in past 6 months
- Body weight >136.4 kg (DXA limit is 300 lbs)
- Smoker (No nicotine within past year)
- Osteoporosis (T-score ≥ -2.5)
- Abnormal kidney function tests
- Insulin-dependent or uncontrolled diabetes
- Uncontrolled hypertension (BP>200/110 mmHg)
- Hypertriglyceridemia (TG>400 mg/dl)
- Past or current ischemic heart disease, angina, heart failure, peripheral artery
disease, stroke, chronic respiratory disease, uncontrolled endocrine/metabolic
disease, neurological or hematological disease, clinically evident edema
- Cancer requiring treatment in past 2 years, except non-melanoma skin cancers
- Severe anemia (Hb<10 g/100 ml)
- Hip fracture, hip or knee replacement, or spinal surgery in past 6 months
- Regular use of medications that influence study variables (growth/steroid hormones,
estrogen, anti-inflammatory, beta blockers, etc.
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