This represents a series of double-blind, controlled pilot randomized studies in which the effects of nitrate-rich beetroot juice and nitrate-depleted beetroot juice will be assessed in patients with heart failure and preserved ejection fraction (n=20). A total of 20 subjects will be enrolled over a 1.5 year period and randomized in a cross-over design to a single dose of nitrate-rich beetroot juice and nitrate-depleted beetroot juice. The order of the interventions will be randomized; thus, all subjects will receive the nitrate-rich and nitrate-depleted juice, with a 4-7 day washout period in-between studies.