Effects of Obesity in the Aged
University of Texas Southwestern Medical Center
Summary
The overall objective of this application is to investigate the effects of obesity on lung function, exercise tolerance, and DOE in older obese adults as compared with older adults without obesity, using a novel probe for mechanically unloading the thorax at rest and during exercise. The investigators will use 1) continuous negative cuirass pressure, and 2) assisted biphasic cuirass ventilation to decrease obesity-related effects in older obese adults. Our approach will be to examine respiratory function, exercise tolerance, and DOE with and without mechanical unloading in older obese men and women (65-75 yr), including those with respiratory symptoms (defined by a score of 1 or 2 on the modified Medical Research Council Dyspnea Scale), as compared with older adults without obesity. Specific Aims: The investigators will test the following hypotheses in older adults with and without obesity: Aim 1) Obesity will decrease respiratory function but to a greater extent in older obese adults with respiratory symptoms, (as evidenced by altered pulmonary function and breathing mechanics at rest); Aim 2) Obesity will decrease exercise tolerance (as evidenced by peak V•O2 in ml/min/kg, i.e., physical fitness), but not cardiorespiratory fitness (as evidenced by peak V•O2 in % of predicted based on ideal body wt), except in older obese adults with respiratory symptoms where both may be reduced during graded cycle ergometry. Aim 3) Obesity will increase DOE but to a greater extent in older obese adults with respiratory symptoms as evidenced by increased ratings of perceived breathlessness (sensory \& affective dimensions) during exercise. Aim 4) Mechanical unloading of the thorax will improve respiratory function, submaximal exercise tolerance, and DOE in older obese adults, but to a greater extent in older obese adults with respiratory symptoms.
Description
Over 40% of older adults (60+ yr) are obese and 30% are overweight. While regular exercise is an important component in the prevention and treatment of obesity, many older adults with obesity are unable or unwilling to exercise due to exercise intolerance and/or dyspnea on exertion (DOE). The Investigators have identified numerous obesity-related respiratory effects that could influence exercise tolerance and DOE in younger obese adults including decreased pulmonary function altered respiratory mechanics increased work of breathing and increased metabolic demands of exercise. The Investigators…
Eligibility
- Age range
- 65–75 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * Otherwise healthy older adults 65-75 years of age with normal lung function; men 30\< %body fat ≤50 and women 35\< %body fat ≤55; and ability to perform pulmonary and exercise test. Other inclusion criteria include the following: * Nonsmokers who have no history of smoking * No personal history of significant mental illness * No weight loss dietary restrictions * No current or past history of significant substance or alcohol abuse * No history, evidence, or uncontrolled symptoms of heart disease * No history of uncontrolled hypertension * No current medications that may…
Interventions
- OtherMechanical unloading of the Thorax using an external cuirass
External cuirass (i.e., a plastic shell over the thorax) will be used to mechanically unload the chest wall. The cuirass has different operating modes. It can generate a constant negative pressure over the chest wall (e.g., -20cmH2O) or it can be triggered off mouth flow so it can generate a negative pressure on the chest wall during inspiration (e.g., -21cmH2O) and a positive pressure during expiration (e.g., +7cmH2O).
Location
- Institute for Exercise and Environmental Medicine, UT Southwestern and Texas Health ResourcesDallas, Texas