Review Article

How Breathing Exercises Influence on Respiratory Muscles and Quality of Life among Patients with COPD? A Systematic Review and Meta-Analysis

Table 1

Baseline demographics, interventions, and clinical characteristics of included studies.

AuthorStudy designParticipantsInterventionOutcome measuresTreatmentJadad score

Beaumont et al. [15]RCTTotal: 34EG: pulmonary rehabilitation and IMT
CG: pulmonary rehabilitation
(1) Lung function: PImax↓, Borg↓Time: 30 min Frequency: 5 d/wk5
EG: 16(2) 6MWD↓Duration: 3 wks
CG: 18(3) QoL : N/A

Beckerman et al. [3]RCTTotal: 42EG: receive IMT for the next year(1) Lung function: PImax↑Time: 30 min6
EG: 21CG: receive training with very low load(2) 6MWT↑Frequency: 6 d/wk
CG: 21(3) QoL : N/ADuration: 12 wks

Berry et al. [16]RCTTotal:17EG: general exercise reconditioning and progressive threshold IMT(1) Lung function: PImax -, FEV1/FVC↑, Borg-Time: 30 min4
EG: 8CG: general exercise reconditioning and sham IMT(2) 6MWT : N/AFrequency: 7 d/wk
CG:9(3) QoL : N/ADuration: 12 wks

Chuang [17]RCTTotal: 55EG: pharmacological therapy, peripheral muscle exercise training, and IMT(1) Lung function: PImax↓,Time: 21–30 min4
EG: 27CG: pharmacological therapy, peripheral muscle exercise training(2) 6MWT↑Frequency: 5 d/wk
CG: 28(3) QoL : N/ADuration: 8 wks

Elmorsi [18]RCTTotal: 40EG: pharmacological therapy, peripheral muscle exercise training, and IMT(1) Lung functionTime: 30 min3
EG: 20CG: pharmacological therapy, peripheral muscle exercise training without IMTPImax↑, PEmax↑,Frequency: 6 d/wk
CG: 20(2) 6MWD↑
(3) QoL:
(1)SGRQ-C total score↓
Duration: 8 wks

Hsiao et al. [19]RCTTotal: 30EG:(2) Lung function: PImax↑Time: 30 min5
EG:TG: receiving pressure threshold IMT(3) 6MWT↑Frequency: 5 d/wk
TG:10TRG: receiving targeted resistive IMT(4) QoL : N/ADuration: 8 wks
TRG: 10CG: no IMT
CG: 10

Larson et al. [20]RCTTotal: 28EG: trained as described above(1) Lung function: PImax↑Time: 30 min4
EG: 14CG: performed at home on a calibrated stationary cycle ergometer(2) 6MWT : N/AFrequency: 5 d/wk
CG: 14(3) QoL : N/ADuration: 16 wk

Li et al. [11]RCTTotal: 36EG: Liuzijue exercise according to the health Qigong Liuzijue program(1) Lung function: FEV1/FVC↑Time: 60 min6
EG: 17CG: pharmacological therapy, smoking cession, and education without any exercise interventions(2) 6MWT↑Frequency: 6 d/wk
CG: 19(3) QoL : N/ADuration: 24 wks

Mota et al. [21]RCTTotal: 16EG: equivalent to around 50% of their maximal expiratory threshold device(1) Lung function: PEmax↑,Time: 30 min5
EG: 10CG: no additional loads(2) FEV1/FVC↓Frequency: 3 d/wk
CG: 6(3) 6MWT : N/A QoL : N/ADuration: 5 wks

Petrovic et al. [22]RCTTotal: 20EG: inspiratory muscle strength and endurance training(1) Lung function: PImax↑, Borg scale↓Time: 15 min4
EG: 10CG: without inspiratory muscle training(2) 6MWT : N/AFrequency: 7 d/wk
CG: 10(3) QoL : N/ADuration: 8 wks

Ramrez-sarmiento et al. [23]RCTTotal: 14EG: through IMT device(1) Lung function:Time: 30 min4
EG: 7CG: through the same IMT device with no additional load(2) PImax↑, PEmax↓Frequency: 5 d/wk
CG: 7(3) 6MWT↑ QoL : N/ADuration: 5 wks

Wang et al. [9]RCTTotal: 55EG: 8 weeks of CET + IMT(1) Lung function: PImax↑, PEmax↓, FEV1/FVC↑,Time: 30 min5
EG: 28CG: 8  eeks of CET alone(2) 6MWT↑Frequency: 3 d/wk
CG: 27(3) QoL : SGRQ, CATDuration: 8 wks

Wankle et al. [24]RCTTotal: 42EG: pharmacological therapy, peripheral muscle exercise training(1) Lung function: PImax↑Time: 30 min4
EG: 21CG: pharmacological therapy, peripheral muscle exercise training, and IMT(2) 6MWT : N/AFrequency: 7 d/wk
CG: 21(3) QoL : N/ADuration: 8 wks

Weiner and Weiner [25]RCTTotal: 28EG: pharmacological treatment with low PIF SIMT(1) Lung function: PImax↑Time: 60 min5
EG: 14CG: only pharmacological treatment(2) 6MWT-Frequency: 6 d/wk
CG: 14(3) QoL : N/ADuration: 8 wks

Wu et al. [26]RCTTotal: 60EG:(1) Lung function: PImax↑, FEV1/FVC↓, dyspneaTime: 30 min4
EG:R-IMT group: using resistive load devices, and IMT(2) 6MWT : N/AFrequency: 7 d/wk
R-IMT: 21,T-IMT group: using threshold load devicesDuration: 8 wks
T-IMT: 19,CG: only with pharmacological therapy without any kind of pulmonary rehabilitation
CG: 20

Xu [8]RCTTotal: 46EG: a half of IMT and a half of no-load respiratory muscle training(1) Lung function: PImax↑, PEmax↓, FEV1/FVCTime: 48 min4
EG: 23CG: no-load respiratory muscle training daily(2) 6MWT-Frequency: 7 d/wk
CG: 23(3) QoL : CAT, SGRQ↓Duration: 8 wks

Yamaguti et al. [27]RCTTotal: 30EG: diaphragmatic breathing training program(1) Lung function: FEV1/FVC↓Time: 45 min5
EG: 15CG: usual care(2) 6MWT↑Frequency: 3 d/wk
CG: 15(3) QoL : SGRQ↓Duration: 4 wks

RCT, randomized controlled trial; EG, experimental group; CG, control group; IMT, inspiratory muscle training; N/A, not available; SEMT, specific expiratory muscle training; SIMT, specific inspiratory muscle training; TG, threshold group; TRG, targeted resistive group; wk, week.