Effectiveness of high-intensity inspiratory muscle training, and resistance and aerobic exercise for cardiovascular health in chronic obstructive pulmonary disease (HIRAC-COPD): a randomized controlled trial protocol

Background Cardiovascular diseases are among the most common and clinically significant comorbidities of chronic obstructive pulmonary disease (COPD). Exercise has been shown to reduce the risk of cardiovascular diseases, and high-intensity inspiratory muscle training (H-IMT) has emerged as a promising intervention for improving arterial stiffness in individuals with COPD. Yet, there is limited evidence from randomized controlled trials (RCTs) regarding the impact of H-IMT alone or in combination with exercise on reducing arterial stiffness in COPD. We designed a three-arm RCT to evaluate the effectiveness of H-IMT, both alone and in combination with exercise, in reducing brachial-ankle pulse wave velocity (baPWV) in individuals with stable COPD within a community setting.

Methods This is a three-arm, parallel-group, assessor-blinded, randomized controlled trial with an eight-week intervention period and a 24-week follow-up. The trial will recruit a total of at least 162 participants with stable COPD. All participants will undergo arterial stiffness assessment using an atherosclerosis detector. Eligible participants will then be randomized into either a control group or one of two intervention groups: an H-IMT group combined with aerobic and resistance trainin, or an H-IMT group alone. The primary outcome is the baPWV at eight weeks. Secondary outcomes include baPWV at 4, 16, and 32 weeks, along with self-reported lifestyle factors, sleep quality, mental health outcomes, self-efficacy, implicit health attitudes, quality of life, and clinical outcomes at 4, 8, 16, and 32 weeks. The main analysis will follow the intention-to-treat principle, with the difference in outcome between groups analyzed using multi-level regression at eight weeks.

Discussion This study will provide evidence on the effects of H-IMT and combined exercise interventions for individuals with COPD in a community setting, offering insights into the use of integrated approaches to enhance cardiovascular health among community-dwelling residents.

Trial registration number ChiCTR2400085483. Date of registration: June 7, 2024. https://www.chictr.org.cn/index.aspx.