Eight-week high-intensity inspiratory muscle training improves cardiac autonomic function in COPD: a randomized...

Area of Science:

• Cardiorespiratory physiotherapy
• Pulmonary rehabilitation
• Autonomic nervous system function

Background:

• COPD is associated with cardiovascular autonomic dysfunction and respiratory muscle weakness.
• Low-intensity inspiratory muscle training (IMT) over 12 weeks can increase cardiac parasympathetic activity.
• The effects of 8-week high-intensity IMT on cardiovascular autonomic function in COPD remain unexplored.

Purpose of the Study:

• To investigate the impact of an 8-week highest tolerable intensity IMT program on cardiovascular autonomic function in stable COPD patients.
• To assess the effects of this IMT intervention on respiratory muscle strength, functional capacity, and health status.

Main Methods:

• Thirty-nine stable COPD patients were randomized into an IMT group or a control group.
• The IMT group performed 30 breaths twice daily at highest tolerable intensity for 8 weeks using a resistive loading device.
• Assessments included pulmonary function, heart rate variability (HRV), blood pressure variability, baroreflex sensitivity, dyspnea, 6-minute walk distance (6MWD), and health status.

Main Results:

• Maximal inspiratory pressure significantly increased in the IMT group.
• Cardiac parasympathetic activity (HRV high-frequency) increased, while sympathetic activity (HRV low-frequency and LF/HF ratio) decreased.
• Significant improvements were observed in 6MWD and health status (COPD Assessment Test, Clinical COPD Questionnaire) in the IMT group compared to the control group.

Conclusions:

• Eight-week highest tolerable intensity IMT effectively enhances cardiovascular autonomic function in COPD patients.
• The intervention leads to increased parasympathetic and reduced sympathetic activity.
• IMT significantly improves functional capacity and health status in individuals with COPD.