Ventilatory Constraint, Breathing Pattern and Ventilatory Responses in Obese Postmenopausal Women

Completed

• Conditions: Obesity; Postmenopausal Women

• Registration Number: NCT01034098
• Lead Sponsor: National Taiwan University Hospital

Brief Summary

The purpose of this study was to examine the dynamic lung volumes in obese post-menopausal women (without hormone replacement therapy) during exercise and their correlations with dyspnea.

Detailed Description

Obesity-related changes in lung volumes have shown to affect breathing mechanisms. During exercise, altered breathing mechanisms increase potential for expiratory flow limitation and compromise exercise capacity. Estrogen and progesterone are potent respiratory stimulants, and their effects in the physiologic regulation of breathing are down-regulated after menopause. Therefore, we theorized that the combined obesity and reduced sex hormone levels after menopause work as a double jeopardy to cause mechanical ventilatory constraint which aggravates dyspnea sensation during exercise, and thus a reduction in exercise capacity. The purpose of this study was to exam the dynamic lung volumes in obese post-menopausal women (without hormone replacement therapy) during exercise and their correlations with dyspnea.

From doctoral referral and advertisement, 24 obese (BMI ≧ 27 kg/m2) and 26 lean post-menopausal women were recruited for the study. Pulmonary function and body composition were measured at rest. A maximal flow volume loop (MFVL) was obtained at baseline. All subjects then performed an incremental exercise test on a cycle ergometer with workload increasing 25 watts every 3 min. During exercise, at each workload, the tidal exercise FV loops were obtained and an inspiratory capacity (IC) maneuver was conducted to assess changes in end-expiratory lung volume (EELV) and end inspiratory lung volume (EILV). Dyspnea and leg fatigue were assessed using the Borg scale. Analysis of variance with repeated measurements was used to test the significance of the mean differences between the two groups during exercise. Linear regression analysis was used to determine whether changes in dynamic lung volumes during exercise were related to changes in Borg scores. Statistical significance was established at p\<0.05.

Study Timeline

• Study Start: 2005-12
• Primary Completion: 2007-04
• Study Completion: 2007-04
• Status Verified: 2009-12
• Study First Submitted: 2009-12-16
• Study First Submitted QC: 2009-12-16
• Last Update Submitted: 2009-12-16
• Study First Posted: 2009-12-17
• Last Update Posted: 2009-12-17

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 50

Inclusion Criteria

• Postmenopausal women (for at least 1 year)
• Age below 69 y/o
• Not receiving hormone replacement therapy

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Exclusion Criteria

• Cardiopulmonary disease
• Musculoskeletal disease affecting results of maximal exercise test

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Dynamic lung volume: end-expiratory lung volume (EELV), end-inspiratory lung volume (EILV)	At least 1 year post-menopause

Secondary Outcome Measures

Name	Time	Method
Pulmonary function	At least 1 year post-menopause
Breathing pattern	At least 1 year post-menopause
Ventilatory response	At least 1 year post-menopause
Visual analog scale (VAS) for dyspnea and leg fatigue	At least 1 year post-menopause

Trial Locations

Locations (1)

School and Graduate Institute of Physical Therapy, National Taiwan University; 🇨🇳 Taipei, Taiwan