Abstract
PURPOSE: Noninvasive ventilation may improve cardiovascular function and exercise performance. We evaluated the physiologic impact of noninvasive ventilation during isokinetic knee extension resistance exercise in patients with heart failure.
METHODS: This clinical trial included 10 male compensated patients with ischemic heart failure (age, 57 +/- 9.1 years; ejection fraction, 28.5 +/- 5.8%). Subjects underwent 2 bouts of exercise on an isokinetic dynamometer, separated by 72 hours of rest. The resistance exercise was concentric knee extension, at a speed of 60[degrees]/s. Five sets of 10 repetitions were performed during the 2 exercise bouts, and each set was separated by 2 minutes of rest. Subjects were administered either bilevel positive airway pressure ventilation (BV) or sham ventilation 20 minutes before and during the 2 exercise sessions in a randomized fashion. Heart rate, systolic blood pressure, and diastolic blood pressure were measured at rest, during exercise, and into recovery. Changes in peak torque ([DELTA]PT), total work ([DELTA]TW), and power ([DELTA]Pw) between the fifth and first sets were also measured.
RESULTS: Compared with the sham intervention, BV significantly decreased heart rate, systolic blood pressure, and diastolic blood pressure at rest and during exercise (P < .01). There were no significant differences in these variables during recovery. Bi-level positive airway pressure ventilation also significantly reduced [DELTA]PT, [DELTA]TW, and [DELTA]Pw compared with the sham intervention (P < .01).
CONCLUSIONS: Bi-level positive airway pressure ventilation significantly improved the cardiovascular response and fatigability during resistance exercise in patients with heart failure. These results suggest that use of BV during exercise training may be beneficial in this population with chronic disease.