DyspneaBreath TestsOxygenOxygen ConsumptionReactive Oxygen SpeciesExhalationOxygen Inhalation TherapyPulmonary Disease, Chronic ObstructiveRespiratory Function TestsRespirationSinglet OxygenForced Expiratory VolumeExercise ToleranceRespiratory MechanicsCarbon DioxideDyspnea, ParoxysmalSpirometryPentanesLung Diseases, ObstructiveBreath HoldingExercise TestLungVital CapacityLactulosePulmonary VentilationTidal VolumePartial PressureHydrogenRespiratory MusclesInhalationAirway ObstructionOxygen IsotopesPulmonary Gas ExchangeLung Volume MeasurementsSeverity of Illness IndexCoughInspiratory CapacityBlood Gas AnalysisTime FactorsLung DiseasesCarbon IsotopesOximetryVolatile Organic CompoundsBreathing ExercisesTreatment OutcomeRadiography, ThoracicAnoxiaHyperbaric OxygenationBronchodilator AgentsLactose IntoleranceRespiratory RateGastric EmptyingUreaHelicobacter pyloriQuality of LifeHelicobacter InfectionsHydrogen PeroxideResidual VolumePulmonary Diffusing CapacityOxidative StressEthaneProspective StudiesRespiratory Physiological PhenomenaOxidation-ReductionRespiratory SoundsHeart FailureAirway ResistanceAdministration, InhalationFatal OutcomeTotal Lung CapacityCarbon MonoxideTomography, X-Ray ComputedLung Diseases, InterstitialScopolamine DerivativesRespiration DisordersReproducibility of ResultsExerciseExpiratory Reserve VolumeAcute DiseaseRespiration, ArtificialHeliumDouble-Blind MethodAcetoneSensitivity and SpecificityHyperventilationBronchial Provocation TestsTracheal DiseasesVolatilizationBiological MarkersAlbuterolHeart NeoplasmsBronchoscopyDiaphragmBronchial DiseasesLactose Tolerance TestHalitosisFunctional Residual CapacityWork of BreathingBronchoconstrictionHemoptysis