BACKGROUND: Dyspnea is a common complaint during daily activities in patients with advanced COPD. The mechanisms underlying dyspnea and the appropriate treatment strategies to relieve it are still not totally understood. We hypothesized that the perception of dyspnea (POD) may be modified by the accumulative effect of bronchodilator therapy, exercise, and inspiratory muscle training (IMT).
METHODS: Spirometry, submaximal exercise performance, inspiratory muscle strength and endurance, and the POD were assessed before and following three consecutive 6-week periods of therapy with a long-acting bronchodilator (LABD), the LABD plus exercise, and the LABD plus exercise plus IMT in 30 patients with moderate-to-severe COPD.
RESULTS: There was a small, statistically insignificant, increase in FEV(1) in the study group (mean [+/- SEM] increase, 1.42+/-0.3 to 1.49+/-0.4 L) following the LABD therapy period, and no additional increase following the two other periods of therapy. There was a significant increase (p<0.05) in the 6-min walk distance following the therapy period with the LABD plus exercise (mean increase, 252+/-41 to 294+/-47 m) and an additional small increase following the therapy period with the LABD plus exercise plus IMT period (mean increase, 252+/-41 to 302+/-49 m). The decrease in the POD was small and statistically not significant following the therapy periods with the LABD and the LABD plus exercise. The major and statistically significant decrease in the POD was noted following the therapy period with the LABD plus exercise plus IMT.
CONCLUSIONS: In patients with moderate-to-severe COPD, following sequential periods of therapy with the LABD, the LABD plus exercise, and the LABD plus exercise plus IMT, there is a cumulative benefit in the POD. The most significant improvement was associated with IMT and not with the LABD and exercise training. The FEV(1) was moderately increased following the therapy period with the LABD, and the addition of exercise has most affected the 6-min walk distance.
PMID: 10988188 DOI: 10.1378/chest.118.3.672

The aim of this study is to assess if an intervention of manual therapy and motor control exercises combined with an inspiratory muscle training program is more effective than an inspiratory muscle training program alone in increasing the maximum inspiratory pressure in patients with asthma. In addition, the study pretends to evaluate the changes caused by the intervention regarding possible postural changes and thoracic diameter.

OBJECTIVE: The aim of the present study was to evaluate the effects that inspiratory muscle training (IMT) and respiratory exercises have on muscle strength, peak expiratory flow (PEF) and severity variables in children with asthma.
METHODS: This was a randomized analytical study involving 50 children with asthma allocated to one of two groups: an IMT group, comprising 25 children submitted to IMT via an asthma education and treatment program; and a control group, comprising 25 children who were submitted only to monthly medical visits and education on asthma. The IMT was performed using a pressure threshold load of 40% of maximal inspiratory pressure (MIP). The results were evaluated using analysis of variance, the chi-square test and Fisher's exact test, values of p > 0.05 being considered significant.
RESULTS: In the comparative analysis, pre- and post-intervention values of MIP, maximal expiratory pressure (MEP) and PEF increased significantly in the IMT group: MIP from -;48.32 +/- 5.706 to -;109.92 +/- 18.041 (p < 0.0001); MEP from 50.64 +/- 6.55 to 82.04 +/- 17.006 (p < 0.0001); and PEF from 173.6 +/- 50.817 to 312 +/- 54.848 (p < 0.0001). In the control group, however, there were no significant differences between the two time points in terms of MIP or MEP, although PEF increased from 188 +/- 43.97 to 208.80 +/- 44.283 (p < 0.0001). There was a significant improvement in the severity variables in the IMT group (p < 0.0001).
CONCLUSIONS: Programs involving IMT and respiratory exercises can increase mechanical efficiency of the respiratory muscles, as well as improving PEF and severity variables.
PMID: 18797738 DOI: 10.1590/s1806-37132008000800003

Large inspiratory pressures may impart stretch to airway smooth muscle and modify the response to deep inspiration (DI) in asthmatics. Respiratory system resistance (Rrs) was assessed in response to 5 inspiratory manoeuvres using the forced oscillation technique: (a) single unloaded DI; (b) single DI at 25 cmH(2)O; (c) single DI at 50% maximum inspiratory mouth pressure [MIP]; (d) 30 DIs at 50% MIP; and (e) 30 DIs at 50% MIP with maintenance of normocapnia. Rrs increased after the unloaded DI and the DI at 25 cmH(2)O but not after a DI at 50% MIP (3.6+/-1.6 hPa Ls(-1) vs. 3.6+/-1.5 hPa Ls(-1); p=0.95), 30 DIs at 50% MIP (3.9+/-1.5 hPa Ls(-1) vs. 4.2+/-2.0 hPa Ls(-1); p=0.16) or 30 DIs at 50% MIP under normocapnic conditions (3.9+/-1.5 hPa Ls(-1) vs. 3.9+/-1.5 hPa Ls(-1); p=0.55). Increases in Rrs in response to DI were attenuated after single and multiple loaded breaths at 50% MIP. PMID: 19442932 DOI: 10.1016/j.resp.2009.03.003

BACKGROUND: This study aimed to investigate whether adjunctive inspiratory muscle training (IMT) can enhance the well-established benefits of pulmonary rehabilitation (PR) in patients with COPD.
METHODS: 219 patients with COPD (FEV1: 42%±16% predicted) with inspiratory muscle weakness (PImax: 51±15 cm H2O) were randomised into an intervention group (IMT+PR; n=110) or a control group (Sham-IMT+PR; n=109) in this double-blind, multicentre randomised controlled trial between February 2012 and October 2016 (ClinicalTrials.gov NCT01397396). Improvement in 6 min walking distance (6MWD) was a priori defined as the primary outcome. Prespecified secondary outcomes included respiratory muscle function and endurance cycling time.
FINDINGS: No significant differences between the intervention group (n=89) and the control group (n=85) in improvements in 6MWD were observed (0.3 m, 95% CI -13 to 14, p=0.967). Patients who completed assessments in the intervention group achieved larger gains in inspiratory muscle strength (effect size: 1.07, p<0.001) and endurance (effect size: 0.79, p<0.001) than patients in the control group. 75 s additional improvement in endurance cycling time (95% CI 1 to 149, p=0.048) and significant reductions in Borg dyspnoea score at isotime during the cycling test (95% CI -1.5 to -0.01, p=0.049) were observed in the intervention group.
INTERPRETATION: Improvements in respiratory muscle function after adjunctive IMT did not translate into additional improvements in 6MWD (primary outcome). Additional gains in endurance time and reductions in symptoms of dyspnoea were observed during an endurance cycling test (secondary outcome) TRIAL REGISTRATION NUMBER: NCT01397396; Results.
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KEYWORDS: exercise; pulmonary rehabilitation; respiratory muscles
PMID: 29914940 DOI: 10.1136/thoraxjnl-2017-211417