Cui J, Iwase S, Mano T, Niimi Y, Fu Q, Michikami D, Atsuta S, Kamiya A, Ushui H
Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
J Gravit Physiol. 2000 Jul;7(2):P133-4.
Exposure to microgravity or simulated microgravity is known to affect regulatory function in autonomic nervous system. With regard to thermoregulation, simulated microgravity impairs sweating and induces lower skin and higher internal temperatures during physical work. During supine rest after HDT bed rest, the internal temperatures were reported to be higher than those of pre-HDT bed rest in some studies but not in others. There is no report about the dynamic changes of skin blood flow during 14-day HDT bed rest. The process of HDT bed-rest deconditioning on the function of the thermoregulatory system is virtually unknown. The HDT induces an immediate cephalad fluid shift which would inhibit the sympathetic outflow through the arterial and cardiopulmonary baroreflexes, which may increase the skin blood flow. On the other hand, prolonged HDT bed rest induces dehydration, which will increase sympathetic outflow through cardiopulmonary baroreceptor modulation. Both sympathetic activation and dehydration itself will decrease skin blood flow. It seems probable that the general effect on skin blood flow may reverse along the HDT bed rest. However, the dynamic characters of skin blood flow and body temperature during the HDT bed rest have not been studied thoroughly. Therefore, the purpose of present study was to investigate the changes of skin blood flow and body temperature during 14 days HDT bed rest.
已知暴露于微重力或模拟微重力环境会影响自主神经系统的调节功能。在体温调节方面，模拟微重力会损害出汗功能，并在体力活动期间导致皮肤温度降低和体内温度升高。在头低位卧床休息后的仰卧休息期间，一些研究报告称体内温度高于头低位卧床休息前，但其他研究则不然。目前尚无关于14天头低位卧床休息期间皮肤血流动态变化的报道。头低位卧床休息对体温调节系统功能的去适应过程实际上尚不清楚。头低位倾斜会立即引起头向体液转移，这将通过动脉和心肺压力反射抑制交感神经输出，这可能会增加皮肤血流。另一方面，长时间的头低位卧床休息会导致脱水，这将通过心肺压力感受器调节增加交感神经输出。交感神经激活和脱水本身都会减少皮肤血流。头低位卧床休息对皮肤血流的总体影响似乎可能会发生逆转。然而，头低位卧床休息期间皮肤血流和体温的动态特征尚未得到充分研究。因此，本研究的目的是调查14天头低位卧床休息期间皮肤血流和体温的变化。
