Relation of changes in oxygen desaturation in thigh muscles and cardiovascular system during the incremental bicycle ergometry

Abstract

The aim of this study was to find out the relation betweenperipheral changes in oxygen desaturation and cardiovas-cular changes during the incremental increase in workload.A synchronous observation of changes in oxygen desatu-ration (StO2) in m.vastus lateralis, changes in arterial bloodpressure and 12 leads ECG during the bicycle ergometrywas performed. In Spectra Tissue Spectrometer, StandartSystem Model 325 was used for the registration of changesin StO2 and a system Kaunas–load was employed for reg-istration and analysis of 12 lead ECG. The subjects (24healthy males) underwent a 50W increase in workload ev-ery 60 seconds (60 revoliutions/min) and they exercised toa predetermined goal (submaximal heart rate) unless dis-tressing cardiovascular symptoms supervened.The results obtained during the study showed that the dy-namics of StO2 was in dependence on the functional pre-paredness of the participant of the study. All participantsof the study can be divided into two groups concerningthe type in changes of StO2 during the workload. Firstgroup – decrease in curve of StO2 up to the end of in-cremental increase in workload and these participants hasdemonstrated higher performance abilities, i.e. more ex-ercise steps performed. The second group – decrease inStO2 curve was observed at onset of exercising but it waschanged to increase of curve during the last steps of exer-cise test. These changes were in coincidence of significantincrease in ST-segment depression.The values of correlation between changes in StO2 andchanges in arterial pulse pressure increased graduallyalong to exercise intensity: r = -0.62 (at 50 W); r = -0.28(at 100 W); r = -0.06 (at 150 W); r = -0.038 (at 200 W); r =0.32 (250 at W); r = 0.53 (at 300 W). The changes in pulsepressure during the exercising are in close relation with thechanges in arterial blood-flow in a calf muscles (Buliuoliset all.) Concerning the results obtained during this studywe conclude that the registered changes.