The effect of dietary nitrate supplementation on the oxygen cost of cycling, walking performance and resting blood pressure in individuals with chronic obstructive pulmonary disease: A double blind placebo controlled, randomised control trial.

•Dietary nitrate reduces the oxygen cost of exercise in healthy individuals.•First dietary nitrate, double-blind, placebo controlled RCT in patients with COPD.•Nitrate supplementation does not lower the oxygen cost of exercise in COPD.•Nitrate supplementation does not improve exercise performance in COPD.•Nitrate supplementation does not reduce blood pressure in COPD.