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Cardiovascular response to treadmill exercise in untrained rats
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1981
Year
Oxygen ExtractionPhysical ActivityAerobic ExerciseCardiovascular FunctionKinesiologyExerciseOxygen ConsumptionPhysical ExerciseApplied PhysiologyCardiologyCardiovascular ResponseHealth SciencesPhysical FitnessMaximal ValuesCardiovascular ReactivityExercise ScienceCardiovascular DiseaseExercise PhysiologyPhysiologyTissue OxygenationCardiovascular PhysiologyMedicine
Oxygen consumption (Vo2), cardiac output (Q), heart rate (HR), stroke volume (SV), and oxygen extraction from blood (Cao2-Cvo2) were measured in untrained rats, both at rest and during treadmill running at various speeds (10-41 m/min). Vo2 increased linearly as a function of running speed, and maximal values (83 ml O2.kg-1 min-1) represented a five-fold increase over resting values. Q, HR, SV, and Cao2-Cvo2 increased linearly as functions of Vo2. Mixed venous oxygen content (Cao2) decreased with increasing Vo2; whereas arterial oxygen content (Cao2) remained independent of Vo2; whereas arterial oxygen content (Cao2) remained independent of Vo2, averaging 19 vol%. Maximal values of these variables and their relationship to Vo2 were as follows: Q = 4.3 Vo2 + 184; Qmax = 543 ml.kg-1.min-1, HR = 3.02 Vo2 + 340; HRmax 595 beats.min-1; SV = 0.004 Vo2 + 0.603; SVmax = 0.92 ml.kg-1.beat-1; Cao2-Cvo2 = 0.13 Vo2 + 5.62; Cao2-Cvo2max = 15.5 vol%.; Cvo2 = -0.12 Vo2 + 12.94; Cvo2min - 3.4 vol%. These data suggest that HR, SV, and Cao2-Cvo2 make significant contributions to the augmentation of Vo2 in the exercising rat.