Effects of home-based high interval inspiratory muscle training on inspiratory muscle strength and exercise capacity in individuals with chronic heart failure

Abstract

Study objective: Heart failure (HF) is a global disease that affects people worldwide. Individuals with HF have symptoms such as dyspnea, fatigue, and exercise intolerance. Inspiratory muscle strength plays an important role in individuals with chronic heart failure (CHF). Recent studies have shown that a long duration (15-30 mins/session) of low-intensity inspiratory muscle training (LI-IMT) improves inspiratory muscle function, exercise capacity, and quality of life in individuals with CHF. However, the long duration of training decreases the compliance of patients. Recently, a short duration (5 mins/session) of high-intensity interval IMT(HI-IMT) was found to improve inspiratory strength and exercise endurance in healthy individuals and individuals with obstructive sleep apnea. To date, the effectiveness of HI-IMT in individuals with HF is unknown. The aim of the study was to examine the effects of HI-IMT in individuals with CHF. The hypothesis of the study was HI-IMT improves inspiratory muscle strength, exercise capacity, and quality of life in individuals with CHF. Methods: This is a randomized control trial. Thirty-six individuals with HF (68% male) were randomly allocated to the HI-IMT group and the control group. Both groups of participants received home-based IMT 6 days/week for 12 weeks. Every session consisted of 30 breaths (5 breaths/set, 6 sets). The intensity of HI-IMT and the control group was 60% and 0% of maximal inspiratory pressure (MIP max ), respectively. Exercise capacity (VO 2 peak and 6-minute walking distance, 6MWD), MIP max , and quality of life (Minnesota living with heart failure questionnaire, MLHFQ) were examined before and after training. Analysis of covariance and paired T-tests were used to examine the training effects. P<0.05 was considered different. Results: Thirty-six individuals with CHF were included in the study. The average age and the left ventricular ejection fraction were 64.7±11.9 years old and 44.5±12.3%, respectively. The improvements of MIP max , 6MWD, VO 2 peak , and MLHFQ were greater in the HI-IMT group than in the control group (p<0.05). The HI-IMT group, but not the control group, showed significant improvements in oxygen uptake efficiency slope after the intervention (p<0.05). Conclusion: 12 weeks of HI-IMT was an effective intervention to improve inspiratory muscle strength, exercise capacity, and quality of life in individuals with CHF. This study was supported by Yen Tjing Ling Medical Foundation, Taiwan. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.