[en] Objective. Analyse the scientific evidence available on the possible benefits of the respiratory muscle training on the lung function, respiratory muscle strength and endurance, exercise tolerance and quality of life. Methods. In this systematic review a search was performed in the PubMed, PEDro, Scopus, Web of Science, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and LILACS databases, using the keywords "breathing exercises", "respiratory muscles", "respiratory therapy", "respiratory function tests", "maximal respiratory pressures", "asthma", "respiratory muscle training", "expiratory muscle training", "inspiratory muscle training" and "respiratory training". Randomized clinical trials and controlled clinical trials without language and date limits were included. Outcomes. We found 10 articles that met the inclusion criteria. All the studies evaluated the effects of inspiratory muscle training (IMT) on asthmatic patients, finding positive results in the increase of the maximal inspiratory pressure (MIP) and in some other variables, such as the decrease in the perception of dyspnoea and the consumption of β2-agonist. Conclusions. Despite the heterogeneity in the IMT dosage, we can conclude that this training produces significant improvements in the increase of respiratory muscle strength, the decrease of the perception of dyspnoea and the decrease of the consumption of β2-agonist. However, there is insufficient scientific evidence that IMT improves lung function, resistance of the respiratory muscles, exercise tolerance, quality of life and the number of hospital admissions. Furthermore, there are no clinical trials that study the efficacy of expiratory muscle training (EMT) in asthma patients.

[gl] Obxectivo. Analizar a evidencia científica dispoñible sobre os posibles beneficios do adestramento da musculatura respiratoria sobre a función pulmonar, a forza e resistencia da musculatura respiratoria, a tolerancia ao exercicio e a calidade de vida. Material e métodos. Nesta revisión sistemática realizouse unha procura nas bases de datos PubMed, PEDro, Scopus, Web of Science, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov e LILACS, empregando as palabras chave "breathing exercises", "respiratory muscles", "respiratory therapy", "respiratory function tests", "maximal respiratory pressures", "asthma", "respiratory muscle training", "expiratory muscle training", "inspiratory muscle training" e "respiratory training". Incluíronse ensaios clínicos aleatorizados e ensaios clínicos controlados sen límites de idioma e data. Resultados. Obtivéronse 10 artigos que cumprisen cos criterios de inclusión. Todos os estudos avaliaron os efectos do inspiratory muscle training (IMT) sobre pacientes asmáticos, atopando resultados positivos no incremento da presión inspiratoria máxima (PIM) e nalgunhas outras variables, como na diminución da percepción de disnea e o consumo de β2- agonista. Conclusións. Pese a que existe heteroxeneidade na dosificación do IMT, podemos concluír que este adestramento produce melloras significativas no aumento da forza muscular respiratoria, na diminución da percepción de dispnea e na diminución do consumo de β2- agonista. Con todo, non existe evidencia científica suficiente sobre que o IMT mellore a función pulmonar, a resistencia da musculatura respiratoria, a tolerancia ao exercicio, a calidade de vida e o número de ingresos hospitalarios. Ademais, non existen ensaios clínicos que estuden a eficacia do expiratory muscle training (EMT) en pacientes con asma.