ANTHROPOLOGY MetaboreceptoFmediated Muscle Oxygen Saturation during Recovery Following Isometric Handgrip Exercise

The aim of the prcscnt study was to deterrnine whethcr oxygcn supply to non-exereiscd muscle during recovery fbllowing fatiguing cxcrcisc is infiuenced by accumulated mctabolitcs within exercised muscle, IXvclvc healthy male subjects performed 2-min isometric handgrip exercise at 40% maximal voluntary contraction with their right hand and the exercise was fbllowed by a 3-min recovery period. Muscle oxygen saturation (Sm02) dctermincd by nearinfrared spatially resolved spcctroscopy was used as an index of oxygen supply to non-cxercised musc]e and was measurcd in biceps brachii and tibialis anterior musclcs on the left side. Compared to the pre-exercise baseline level, Sm02 in the biceps brachii muscle (SmO,BB) increased significantly from 30 sec to 1 min after the start of exercise, whi]e Sm02 in the tibialis antcrior muscle (Sm02m) rernained stable during the initial 1 rnin of exercise. Both Sm02BB and Sm02TA began to decrease at about 1 min and continued to decrease thereaftcr, Due to the initial increase in Sm02BB, only Sm02Ts showed a significant decrcasc during exercise. During recovery, Sm02BB did not differ significantly from the pre-cxcrcisc baseLine ievel, whereas Sm02-N remained significantly lower until about 1,5 min ofrecovery and thcn it did not di ffer significantly from the baseline lcvel. In another bout, subjects per{brmed handgrip exercise of the same intensity, but post-cxercise arterial occlusion (PEAO) of the exercised muscle was imposed for 2 min immediately aftcr the end of exereise. During PEAO. SniO?BB decreased sjgnlficantly compared to the baseline ]cvcl, whereas Sm02TA rcmaincd significantly ]ower until the end of PEAO, The sjgnificant decrease in SmOnR and thc prolongation ofdccrcasc in Sm02TA by PEAO suggests that the recovery ofSrn02 in the non-exercised arm and leg is mcdiated by muscle metaboreceptors, JPdysiolAnthmpol 27av.' 83-9i, 2008http:/lwww.jstage.jst.go,jpibrowseijpa2 [DOI: 10.2214ijpa2.27.83]