Key Takeaway
Respiratory muscle training improved exercise capacity (6MWD +46.45 m), maximal inspiratory pressure (+17.02 cmH2O), and quality of life in patients with ischemic heart disease.
Summary
This systematic review and meta-analysis evaluated the effects of respiratory muscle training (RMT) on exercise capacity, quality of life, respiratory function, and pulmonary function in people with ischemic heart disease. The authors conducted a comprehensive search of PubMed, Cochrane Library, PEDro, Embase, CINAHL, and Web of Science, ultimately including 12 randomized controlled trials with 465 participants.
The meta-analysis demonstrated that RMT — primarily inspiratory muscle training — produced clinically meaningful improvements in functional exercise capacity, as measured by the 6-minute walk test, and significantly increased maximal inspiratory pressure. Quality of life also improved, as assessed by the Minnesota Living with Heart Failure Questionnaire.
These findings suggest that RMT is a safe and effective adjunct to conventional cardiac rehabilitation for patients with ischemic heart disease. The improvements in exercise tolerance and respiratory muscle strength are particularly relevant given that inspiratory muscle weakness is common in heart disease patients and contributes to exercise intolerance and dyspnea.
Methods
Systematic review and meta-analysis of 12 RCTs (465 participants) from 6 databases. Included studies compared RMT (primarily IMT using threshold devices at 30-60% MIP) to usual care or sham training in patients with ischemic heart disease. Outcomes included 6-minute walk distance (6MWD), MIP, FEV1, FVC, and quality of life. Methodological quality assessed using PEDro scale.
Key Results
RMT significantly improved 6-minute walk distance (MD = +46.45 m, 95% CI: 21.14-71.76), maximal inspiratory pressure (MD = +17.02 cmH2O, 95% CI: 8.30-25.74), and quality of life scores. Improvements in FEV1 and FVC were observed but did not reach statistical significance in all analyses. The magnitude of improvement in 6MWD exceeded the minimal clinically important difference of 30 meters.
Limitations
Relatively small number of included studies (12 RCTs) with modest sample sizes. Heterogeneity in training protocols (device type, intensity, duration, and frequency). Most studies focused on IMT specifically, limiting conclusions about expiratory muscle training. Limited long-term follow-up to assess durability of benefits. Publication bias could not be fully excluded.