Aerobic and breathing exercises improve dyspnea, exercise capacity and quality of life in idiopathic pulmonary fibrosis patients: systematic review and meta-analysis

Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive disease associated with significant dyspnea and limited exercise capacity. This systematic review aimed to synthesize evidence of exercise interventions during pulmonary rehabilitation that aim to improve exercise capacity, dyspnea, and health-related quality of life (HRQL) in IPF patients.

Methods: Searches were performed in MEDLINE, Embase, CENTRAL, SPORTDiscus, PubMed and PEDro from inception to January 2019 using search terms for: (I) participants: 'IPF or interstitial lung disease'; (II) interventions: 'aerobic training or resistance training or respiratory muscle training'; and (III) outcomes: 'exercise capacity or dyspnea or health-related quality of life'. Two reviewers independently screened titles, abstracts and full texts to identify eligible studies. Methodological quality of studies was assessed using the Downs and Black checklist and meta-analyses were performed.

Results: Of 1,677 articles identified, 14 were included (four randomized controlled trials and 10 prospective pre-post design studies) that examined 362 patients receiving training and 95 control subjects. Exercise capacity was measured with the 6-minute walk distance, peak oxygen consumption, peak work rate, or endurance time for constant work rate cycling, which increased after exercise [aerobic exercise; aerobic and breathing exercises; aerobic and inspiratory muscle training (IMT) exercises] compared to the control groups. Dyspnea scores improved after aerobic and breathing exercises. HRQL also improved after aerobic exercise training alone or combined with breathing exercises. Aerobic training alone or combined with IMT or breathing exercises improved exercise capacity.

Conclusions: Breathing exercises appears to complement exercise training towards improved dyspnea and HRQL in patients with IPF.

Keywords: Dyspnea; exercise; interstitial lung diseases; quality of life; rehabilitation.

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

2020 Journal of Thoracic Disease. All rights reserved.

Figures

Figure 1

Flow chart of retrieval, screening and inclusion of articles in systematic review.

Figure 2

Change in 6-minute walk distance (m). (A) Exercise versus control; (B) pre and post exercise. Symbols: for single studies, the squares indicate the mean difference and the relative size of the square is an indication of the weighting of this study towards the overall effect. The endpoints of the horizontal lines are the upper and lower 95% confidence interval. The large diamonds represent the summed data for the subgroups and all studies included in the meta-analysis; the midpoint of the diamond indicates the mean difference whereas the endpoints are the upper and lower 95% confidence interval. 95% CI, 95-percent confidence interval; IV, inverse variance; SD, standard deviation.

Figure 3

Change in cycle ergometry outcome. (A) Peak work rate (watt)—exercise versus control; (B) peak work rate (watt)—pre and post exercise; (C) constant work rate endurance time (s)—exercise versus control; (D) Constant work rate endurance time (s)—pre and post exercise. Symbols: for single studies, the squares indicate the mean difference and the relative size of the square is an indication of the weighting of this study towards the overall effect. The endpoints of the horizontal lines are the upper and lower 95% confidence interval. The large diamonds represent the summed data for the subgroups and all studies included in the meta-analysis; the midpoint of the diamond indicates the mean difference whereas the endpoints are the upper and lower 95% confidence interval. 95% CI, 95-percent confidence interval; IV, inverse variance; SD, standard deviation.

Figure 4

Change in dyspnea score. (A) Exercise versus control; (B) % improvement of pre and post exercise. Symbols: for single studies, the squares indicate the mean difference and the relative size of the square is an indication of the weighting of this study towards the overall effect. The endpoints of the horizontal lines are the upper and lower 95% confidence interval. The large diamonds represent the summed data for the subgroups and all studies included in the meta-analysis; the midpoint of the diamond indicates the mean difference whereas the endpoints are the upper and lower 95% confidence interval. 95% CI, 95-percent confidence interval; IV, inverse variance; SD, standard deviation.

Figure 5

Change in St. George’s Respiratory Questionnaire (point). (A) Exercise versus control; (B) Pre and post exercise. Symbols: for single studies, the squares indicate the mean difference and the relative size of the square is an indication of the weighting of this study towards the overall effect. The endpoints of the horizontal lines are the upper and lower 95% confidence interval. The large diamonds represent the summed data for the subgroups and all studies included in the meta-analysis; the midpoint of the diamond indicates the mean difference whereas the endpoints are the upper and lower 95% confidence interval. 95% CI, 95-percent confidence interval; IV, inverse variance; SD, standard deviation.

Figure 6

The 36-item Short-Form Health Survey (SF-36) pre versus post-exercise. Symbols: for single studies, the squares indicate the mean difference and the relative size of the square is an indication of the weighting of this study towards the overall effect. The endpoints of the horizontal lines are the upper and lower 95% confidence interval. The large diamonds represent the summed data for the subgroups and all studies included in the meta-analysis; the midpoint of the diamond indicates the mean difference whereas the endpoints are the upper and lower 95% confidence interval. 95% CI, 95-percent confidence interval; IV, inverse variance; SD, standard deviation.