Dietary Nitrate Increases VO2peak and Performance but Does Not Alter Ventilation or Efficiency in Patients With Heart Failure With Reduced Ejection Fraction

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 (NO3-), a source of nitric oxide (NO), has improved these measures in some studies of other populations. We determined the effects of acute NO3- ingestion on exercise responses in 8 patients with HFrEF using a randomized, double-blind, placebo-controlled, crossover design. Methods and Results: Plasma NO3-, nitrite (NO2-), 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 NO3-. NO3- intake increased (P <.05-0.001) plasma NO3- and NO2- and breath NO by 1469 +/- 245%, 105 +/- 34%, and 60 +/- 18%, respectively. Efficiency and ventilation during exercise were unchanged. However, NO3- 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 NO3- intake increases VO(2)peak and performance in patients with HFrEF. These data, in conjunction with our recent data demonstrating that dietary NO3- also improves muscle contractile function, suggest that dietary NO3- supplementation may be a valuable means of enhancing exercise capacity in this population.