Chest
Volume 120, Issue 3, September 2001, Pages 748-756
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Clinical Investigations
Muscle Strength
Inspiratory Muscle Training in Patients With COPD: Effect on Dyspnea, Exercise Performance, and Quality of Life

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Abstract

Objective

The aim of the study was to assess the effect of target-flow inspiratory muscle training (IMT) on respiratory muscle function, exercise performance, dyspnea, and health-related quality of life (HRQL) in patients with COPD.

Patients and methods

Twenty patients with severe COPD were randomly assigned to a training group (group T) or to a control group (group C) following a double-blind procedure. Patients in group T (n = 10) trained with 60 to 70% maximal sustained inspiratory pressure (SIPmax) as a training load, and those in group C (n = 10) received no training. Group T trained at home for 30 min daily, 6 days a week for 6 months.

Measurements

The measurements performed included spirometry, SIPmax, inspiratory muscle strength, and exercise capacity, which included maximal oxygen uptake (

o2), and minute ventilation (
e). Exercise performance was evaluated by the distance walked in the shuttle walking test (SWT). Changes in dyspnea and HRQL also were measured.

Results

Results showed significant increases in SIPmax, maximal inspiratory pressure, and SWT only in group T (p < 0.003, p < 0.003, and p < 0.001, respectively), with significant differences after 6 months between the two groups (p < 0.003, p < 0.003, and p < 0.05, respectively). The levels of

o2 and
e did not change in either group. The values for transitional dyspnea index and HRQL improved in group T at 6 months in comparison with group C (p < 0.003 and p < 0.003, respectively).

Conclusions

We conclude that targeted IMT relieves dyspnea, increases the capacity to walk, and improves HRQL in COPD patients.

Section snippets

Patients

Twenty patients with COPD were selected from the outpatient clinic. Patients were randomly assigned to the training group (group T) or to a control group (group C) on a double-blind basis. Table 1 shows the baseline characteristics of the patients. All patients had severe airflow obstruction (ie, FEV1< 50%) and were included with the presence of COPD as defined by the American Thoracic Society.9 Patients were in stable condition and were free of any clinical evidence of cardiovascular,

Results

All selected patients completed the study. There were no significant differences between the two groups at the start of the study. The general characteristics and pulmonary function data are presented in Table 1.

Discussion

This study shows that in COPD patients, IMT at home using an incentive flowmeter device (target-flow) diminishes dyspnea and improves respiratory muscle function, exercise performance, and HRQL.

The baseline characteristics of the two groups were similar. Although the trained patients were not supervised while performing the training at home, we assume from the tests performed in the laboratory throughout the study period that they followed the same regimen at home. In addition, the study shows

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    Supported by “Junta de Andalucia” grant No. 94//535–119.

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