It has been shown that the inspiratory muscles of patients with congestive heart failure (CHF) are weaker than normal. This weakness may contribute to dyspnea and limit exercise capacity. But respiratory muscles can be trained for increase in both strength and endurance. This study was designed to evaluate the effect of specific inspiratory muscle training (SIMT) on muscular performance, lung function, dyspnea and exercise capacity in moderate heart failure. 10 patients with CHF (NYHA functional class II-III) received 1/2 hour of SIMT daily, 6 times/week, for 3 months. They started breathing at a resistance 15% of their Pimax for 1 week and the resistance was then increased incrementally to 60%. Spirometry, inspiratory muscle strength and endurance, and the 12-minute walk test were performed before and after the training period. All showed an increase in inspiratory muscle strength and endurance. This was associated with a small but significant increase in FVC, a significant increase in the distance walked (458 +/- 29 to 562 +/- 32 m, p < 0.01), and improvement in the dyspnea index score. SIMT resulted in increased inspiratory muscle strength and endurance. This increase was associated with decreased dyspnea and an increase in submaximal exercise capacity. SIMT may prove to be useful complementary therapy in CHF.
PMID: 10955110

BACKGROUND: Diminished respiratory muscle strength and endurance have been demonstrated in patients with heart failure. This may contribute to exertional dyspnea and reduced exercise capacity in these patients. The purpose of this study was to investigate whether selective respiratory muscle training could alleviate dyspnea and improve exercise performance in patients with chronic congestive heart failure.
METHODS AND RESULTS: Fourteen patients with chronic heart failure (left ventricular ejection fraction, 22 +/- 9%) were enrolled in a supervised respiratory muscle training program. This consisted of three weekly sessions of isocapnic hyperpnea at maximal sustainable ventilatory capacity, resistive breathing, and strength training. Maximum sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory and expiratory pressures, peak VO2, and the 6-minute walk test were measured before (pre) and after (post) 3 months of training. Eight patients completed the training program. Respiratory muscle endurance was improved with training, as evidenced by increases in maximal sustainable ventilatory capacity (pre, 48.6 +/- 10.7 versus post, 76.9 +/- 14.5 L/min; P < .05) and in maximal voluntary ventilation (pre, 100 +/- 36 versus post, 115 +/- 39 L/min; P < .05). Respiratory muscle strength was also increased with training as maximal inspiratory (pre, 64 +/- 31 versus post, 78 +/- 33 cm, H2O; P < .01) and expiratory (pre, 94 +/- 30 versus post, 133 +/- 53 cm H2O; P < .001) pressures rose. Submaximal and maximal exercise capacity were significantly improved with selective respiratory muscle training as the 6-minute walk (pre, 1101 +/- 351 versus post, 1421 +/- 328 ft; P < .001) and peak exercise VO2 (pre, 11.4 +/- 3.3 versus post, 13.3 +/- 2.7 mL.kg-1.min-1; P < .05) both significantly increased. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients. Dyspnea quantified by the Borg scale was significantly reduced during progressive isocapnic hypernea but not during bicycle exercise. No statistically significant improvement in maximal sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory or expiratory mouth pressures, 6-minute walk, or peak VO2 was observed in the 6 patients who did not complete the training program.
CONCLUSIONS: Selective respiratory muscle training improves respiratory muscle endurance and strength, with an enhancement of submaximal and maximal exercise capacity in patients with heart failure. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients.
PMID: 7805234 DOI: 10.1161/01.cir.91.2.320

People with heart failure (HF) are living longer but with disabling dyspnea that erodes quality of life (QOL). Decreased strength of inspiratory muscles (IMs) may contribute to dyspnea in HF, and inspiratory muscle training (IMT) has been shown to improve the strength of IMs. The purpose of this study was to determine the effects of a 3-month nurse-coached IMT program. Bandura's Self-Efficacy Theory directed nursing interventions. This randomized controlled trial employed an experimental group (IMT) and a control group (education). Data were collected during six home visits. Outcome measures included maximal inspiratory pressure, perceived dyspnea, self-efficacy, and health-related QOL. Significant differences in PI(max), dyspnea, and respiratory rate were found. Implications for further research and practice are discussed.
PMID: 19171291 DOI: 10.1016/j.apnr.2007.02.002

BACKGROUND: The effects of inspiratory muscle training on plasma cytokines, C-reactive protein and the soluble apoptosis mediators Fas and Fas ligand in chronic heart failure are unknown.
DESIGN AND METHODS: Thirty-eight patients with chronic heart failure, age 57+/-2 years, New York Heart Association classification II-III, were assigned to either a high intensity training group (n=15, age 53+/-2 years) exercised at 60% of sustained maximal inspiratory pressure, or a low intensity training group (n=23, age 59+/-2 years), exercised at 15% of sustained maximal inspiratory pressure, three times per week for 10 weeks. Patients in the high intensity training group and low intensity training group were matched for age, sex and New York Heart Association functional class. Plasma levels of tumor necrosis factor (TNF)-alpha, soluble TNF receptor I, interleukin-6, C-reactive protein, soluble apoptosis mediators Fas and Fas ligand were measured at baseline and at post-inspiratory muscle training. Pulmonary function was assessed by spirometry, exercise capacity by a cardiopulmonary exercise test and the 6 min walk test, whereas dyspnea by the Borg scale after the 6 min walk test.
RESULTS: High intensity training group improved inspiratory muscle strength (105.1+/-4.9 vs. 79.8+/-4.7 cmH2O, P<0.001), sustained maximal inspiratory pressure (504.5+/-39.7 vs. 312.5+/-26.5 cmH2O/s/10, P<0.001), forced vital capacity (98.9+/-3.9 vs. 96+/-3.3%, P<0.05), peak VO2 (19.4+/-1.2 vs. 17.3+/-0.9 ml/kg per min, P<0.01), 6 min walk test distance (404.3+/-11.9 vs. 378.2+/-10.4 m, P<0.01) and dyspnea (8.0+/-0.4 vs. 9.2+/-0.4, P<0.01). Circulating TNF-alpha, soluble TNF receptor I, interleukin-6, C-reactive protein, soluble apoptosis mediators Fas and Fas ligand were not significantly altered. Low intensity training group increased only the inspiratory muscle strength (90.3+/-5.9 vs. 80.2+/-5 cmH2O, P<0.01). Comparison between groups was significant for soluble TNF receptor I change (high intensity training group, 5.8+/-0.49 vs. 6.1+/-0.42; low intensity training group, 8.4+/-0.6 vs. 7.8+/-0.6, P<0.01).
CONCLUSION: A high intensity inspiratory muscle training program resulted in improvement in functional status of chronic heart failure patients compared with low intensity inspiratory muscle training. Improvement in exercise capacity was not associated with an anti-inflammatory effect, although a beneficial influence on soluble TNF receptor I was recorded. Possible reasons include inadequate level of muscle mass exercise and the low pretraining New York Heart Association class.
PMID: 17925628 DOI: 10.1097/HJR.0b013e3281338394

PURPOSE: Studies have reported the benefits of exercise and inspiratory muscle training (IMT) in patients with heart failure (HF); however, there is no meta-analysis on the effects of the combination of exercise and IMT in patients with HF. The objective of this study was to determine whether combined exercise/IMT was more effective than conventional exercise on exercise capacity, respiratory muscle strength, and quality of life in patients with HF.
METHODS: This is a systematic review and meta-analysis. We searched MEDLINE, LILACS, CINAHL, EMBASE, PEDro, and the Cochrane Central Register of Controlled Trials (from the earliest date available to April 2015) for randomized controlled trials, examining effects of combined exercise/IMT versus conventional exercise on exercise capacity, respiratory muscle strength, and quality of life measurements in patients with HF. Two reviewers selected studies independently. Weighted mean differences and 95% CIs were calculated.
RESULTS: Three studies met the study criteria. Combined exercise/IMT resulted in improvement in maximal inspiratory pressure weighted mean differences (20.89 cm H2O; 95% CI, 14.0-27.78) and Minnesota Living with Heart Failure Questionnaire weighted mean differences (4.43; 95% CI, 0.72-8.14). Nonsignificant difference was observed in peak (Equation is included in full-text article.)O2 for participants in the combined exercise/IMT group compared with the conventional exercise group. No serious adverse events were reported.
CONCLUSIONS: Combined exercise/IMT may improve maximal inspiratory pressure and quality of life in patients with HF and should be considered for inclusion in cardiac rehabilitation programs.
PMID: 27182763 DOI: 10.1097/HCR.0000000000000184