Dietary Nitrate Increases VO 2 peak 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 (VO2 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) VO2 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 VO2 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.