The Journal of Cardiopulmonary Rehabilitation & Prevention published the following clinical trial to evaluate the effect of inspiratory muscle training (IMT) on cardiac autonomic modulation and on peripheral nerve sympathetic activity in patients with chronic heart failure (CHF).
The Clinical Trial:
Functional capacity, low-frequency (LF) and high-frequency (HF) components of heart rate variability, muscle sympathetic nerve activity inferred by microneurography, and quality of life were determined in 27 patients with CHF who had been sequentially allocated to 1 of 2 groups: (1) control group (with no intervention) and (2) IMT group. Inspiratory muscle training consisted of respiratory exercises, with inspiratory threshold loading of seven 30-minute sessions per week for a period of 12 weeks, with a monthly increase of 30% in maximal inspiratory pressure (PImax) at rest. Multivariate analysis was applied to detect differences between baseline and follow up period.
Inspiratory muscle training significantly increased PImax (59.2 +/- 4.9 vs 87.5 +/- 6.5 cmH2O, P = .001) and peak oxygen uptake (14.4 +/- 0.7 vs 18.9 +/- 0.8 mL[middle dot]kg-1[middle dot]min-1, P = .002); decreased the peak ventilation (VE)/carbon dioxide production (VCO2) ratio (35.8 +/- 0.8 vs 32.5 +/- 0.4, P = .001) and the VE VCO2 slope (37.3 +/- 1.1 vs 31.3 +/- 1.1, P = .004); increased the HF component (49.3 +/- 4.1 vs 58.4 +/- 4.2 normalized units, P = .004) and decreased the LF component (50.7 +/- 4.1 vs 41.6 +/- 4.2 normalized units, P = .001) of heart rate variability; decreased muscle sympathetic nerve activity (37.1 +/- 3 vs 29.5 +/- 2.3 bursts per minute, P = .001); and improved quality of life. No significant changes were observed in the control group.
Home-based IMT represents an important strategy to improve cardiac and peripheral autonomic controls, functional capacity, and quality of life in patients with CHF.
(C) 2012 Lippincott Williams & Wilkins, Inc.
You can read the Abstract here on the Journal of Cardiopulmonary Rehabilitation and Prevention website.
In patients with chronic heart failure, inspiratory muscle training, such as with the POWERbreathe Medic, has been shown to:
- Improve exercise tolerance by 19%
- Improve quality of life by 16%