Abstract
BACKGROUND: Patients with heart failure with reduced ejection fraction (HFrEF) exhibit lower efficiency, dyspnea, and diminished peak oxygen uptake (VO(2)peak) during exercise. Dietary nitrate (NO(3)(-)), a source of nitric oxide (NO), has improved these measures in some studies of other populations. We determined the effects of acute NO(3)(-) ingestion on exercise responses in 8 patients with HFrEF using a randomized, double-blind, placebo-controlled, crossover design. METHODS AND RESULTS: Plasma NO(3)(-), nitrite (NO(2)(-)), and breath NO were measured at multiple time points and respiratory gas exchange was determined during exercise after ingestion of beetroot juice containing or devoid of 11.2 mmol of NO(3)(-). NO(3)(-) intake increased (P < .05-0.001) plasma NO(3)(-) and NO(2)(-) and breath NO by 1469 ± 245%, 105 ± 34%, and 60 ± 18%, respectively. Efficiency and ventilation during exercise were unchanged. However, NO(3)(-) ingestion increased (P < .05) VO(2)peak by 8 ± 2% (ie, from 21.4 ± 2.1 to 23.0 ± 2.3 mL(.)min(-1.)kg(-1)). Time to fatigue improved (P < .05) by 7 ± 3 % (ie, from 582 ± 84 to 612 ± 81 seconds). CONCLUSIONS: Acute dietary NO(3)(-) intake increases VO(2)peak and performance in patients with HFrEF. These data, in conjunction with our recent data demonstrating that dietary NO(3)(-) also improves muscle contractile function, suggest that dietary NO(3)(-) supplementation may be a valuable means of enhancing exercise capacity in this population.