Lee C F, Katsuura T, Harada H, Iwanaga K, Kikuchi Y
Department of Ergonomics, Graduate School of Science and Technology, Chiba University.
Appl Human Sci. 1995 Sep;14(5):211-8. doi: 10.2114/ahs.14.211.
We studied the circulatory regulation during intermittent isometric handgrip (IIHG, six seconds contraction + six seconds relaxation) in supine and sitting postures in a hot environment (40 degrees C, RH: 50%). Eight healthy male subjects performed thrice 5-minute period IIHG at three different work loads (10%, 20% and 30% MVC). The IIHG was performed with the right hand in the two postures. Heart rate (HR), cardiac output (CO), mean arterial blood pressure (MBP), forearm blood flow (FBF), skin blood flow (SBF), foot swelling (FSW) and tympanic temperature (Tty) were measured during IIHG, resting and recovery periods. During IIHG in a hot environment, HR, MBP, FSW and Tty showed higher values in the sitting than in the supine posture. FBF during relaxation showed higher values at high work load than at low work load in the two postures. FBF showed higher values in the sitting than in the supine posture, except during relaxation at 30% MVC. It was concluded that the decrements of blood volume of splanchnic organs might be greater in the sitting than in the supine posture due to sympathetic vasoconstrictor activity, and were responsible for the redistribution of blood flow. Posture had an effect on FBF because of hydrostatic pressure.
我们研究了在炎热环境（40摄氏度，相对湿度：50%）中，仰卧位和坐位时进行间歇性等长握力运动（IIHG，6秒收缩+6秒放松）期间的循环调节。八名健康男性受试者在三种不同工作负荷（10%、20%和30%最大自主收缩力）下进行三次5分钟的IIHG。IIHG用右手在两种姿势下进行。在IIHG、静息期和恢复期测量心率（HR）、心输出量（CO）、平均动脉血压（MBP）、前臂血流量（FBF）、皮肤血流量（SBF）、足部肿胀（FSW）和鼓膜温度（Tty）。在炎热环境中进行IIHG时，坐位时的HR、MBP、FSW和Tty值高于仰卧位。在两种姿势下，放松期间FBF在高工作负荷时的值高于低工作负荷时的值。除了在30%最大自主收缩力放松期间，坐位时的FBF值高于仰卧位。得出的结论是，由于交感神经血管收缩活动，坐位时内脏器官血容量的减少可能比仰卧位时更大，并且这是血流重新分布的原因。由于静水压力，姿势对FBF有影响。
