Respiratory muscle training (RMT) effectively improves respiratory muscle strength in patients with respiratory muscle weakness, such as chronic heart failure (CHF) patients. It is unclear to date, however, whether this improvement leads to improved ventilation during exercise. As a decreased capacity for exercise is a common issue for CHF patients and can have a marked negative effect upon their quality of life, the potential for RMT to improve said ventilation is an important one to explore. Measuring the oxygen uptake efficiency slope (OUES), then, provides an evaluation of how efficiently the lungs extract oxygen and supply it to the periphery during ventilation.

To study the effect of RMT on the OUES, research was conducted. The study in question tests the efficiency of RMT to improve OUES during incremental exercise in patients with CHF. Let’s take a look at the study in a bit more detail below.

Key Findings

• Respiratory muscle training (RMT) improves respiratory muscle strength in people with chronic heart failure (CHF), but its effect on ventilation during exercise is unclear.
• Measurement of the oxygen uptake efficiency slope (OUES) provides an evaluation of how efficiently the lungs extract oxygen and supply it to the periphery during ventilation.
• 12 weeks of RMT improved respiratory muscle strength and OUES in people with CHF.
• Respiratory muscle strength and OUES strongly correlate.

Patient Impact

RMT effectively improves ventilation and incremental exercise capacity in CHF patients, and respiratory muscle strength is a predictor for peripheral muscle capacity./p>

Study Methods

Patients with CHF underwent 12 weeks of RMT using an inspiratory muscle trainer at low intensity. Assessment of inspiratory muscle pressure (PImax) and OUES were performed at the beginning and end of the study, and compared to a control group with SHAM RMT. OUES was then calculated from oxygen uptake (VO2) and minute ventilation (VE) data collected during an incremental treadmill exercise. The patients’ progress was also compared to that of participants in a control group.

Study Results

PImax and OUES significantly improved as a result of RMT when compared to the control group. In addition, PImax and OUES showed a strong correlation, showing that inspiratory muscle strength is an important determinant for OUES.

In conclusion, RMT directly improves ventilation and incremental exercise capacity in CHF patients, which is a clinically meaningful prognostic marker. Respiratory muscle strength is correlated with OUES, showing that respiratory muscle function can predict and is connected to peripheral muscle capacity. RMT, therefore, does help to improve ventilation during exercise and can significantly improve a CHF patient’s quality of life.

References

Stein R, et al. Inspiratory muscle training improves oxygen uptake efficiency slope in patients with chronic heart failure. J. Cardiopulm. Rehabil. Prev. 29(6),392–395 (2009).