Heart RatePhysical ExertionPropanolaminesBetaxololXamoterolAtenololExercise TestAcebutololPropranololOxprenololAdrenergic beta-AntagonistsExerciseMetoprololHeartPindololOxygen ConsumptionBlood PressureExercise TherapyHemodynamicsDouble-Blind MethodExercise ToleranceHeart FailureHeart Rate, FetalPhysical EnduranceAutonomic Nervous SystemHeart DiseasesMuscle, SkeletalRestHeart TransplantationTime FactorsHeart Defects, CongenitalElectrocardiographySympathetic Nervous SystemBicyclingFetal HeartBaroreflexPhysical FitnessRespirationElectrocardiography, AmbulatoryCardiovascular Physiological PhenomenaCardiac OutputStroke VolumeRunningAnaerobic ThresholdMyocardial ContractionLactic AcidHeart Function TestsPulmonary Gas ExchangeHeart AtriaMyocardiumRegional Blood FlowCoronary DiseaseHeart BlockVentricular Function, LeftDogsResistance TrainingHeart ValvesParasympathetic Nervous SystemTelemetryMuscle Stretching ExercisesEnergy MetabolismNorepinephrineOxygenBradycardiaTreatment OutcomeCardiovascular SystemPhysical Education and TrainingEchocardiographyProspective StudiesAnalysis of VarianceEpinephrineCross-Over StudiesBody TemperatureAdaptation, PhysiologicalLegPostureReference ValuesTachycardiaBreathing ExercisesReflexPressoreceptorsAtropineRisk FactorsCardiotonic AgentsCardiac Output, LowSupine PositionFollow-Up StudiesMyocardial InfarctionMyocardial IschemiaBody WeightVentricular Dysfunction, LeftCatecholaminesSportsSystoleChronic DiseaseSinoatrial NodeCarbon DioxideRats, WistarRats, Sprague-DawleyDiastole