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 .