Effects of Obesity in the Aged

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.

Conditions

• Obesity
• Aging

Interventions

OTHER

Mechanical 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).

Sponsors & Collaborators

• National Institute on Aging (NIA)

  collaborator NIH

• University of Texas Southwestern Medical Center

  lead OTHER

Principal Investigators

• Tony G Babb, Ph.D. · UT Southwestern Medical Center

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

65 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-12-01

Primary Completion

2026-08-31

Completion

2026-08-31

Countries

• United States

Study Locations