Beta vulgarisNitratesNitritesDietary SupplementsHeart RateBeveragesDietHeartCross-Over StudiesNitrate ReductaseBlood PressureSalivaDouble-Blind MethodAutonomic Nervous SystemStomachDietary FatsNitric OxideDietary ProteinsAnimal FeedFood, FortifiedHeart FailureAdrenergic beta-AntagonistsElectrocardiographyDietary FiberElectrocardiography, AmbulatoryRandom AllocationVitaminsParasympathetic Nervous SystemTime FactorsPropranololHemodynamicsPlacebosVitamin AAnimal Nutritional Physiological PhenomenaZincAtropineVitamin ESympathetic Nervous SystemBody WeightDietary CarbohydratesDose-Response Relationship, DrugMicronutrientsVagus NerveOxprenololFolic AcidHeart Rate, FetalPhysical ExertionPressoreceptorsAtenololFish OilsAnalysis of VarianceDogsExercise TestBaroreflexbeta Carotene