Gerzer R, Heer M, Drummer C
Institute of Aerospace Medicine, DLR, Cologne, Germany.
Med Sci Sports Exerc. 1996 Oct;28(10 Suppl):S32-5. doi: 10.1097/00005768-199610000-00030.
Recent observations from space missions indicate that weightlessness does not induce an increase in diuresis and natriuresis in astronauts. Rather, both oral fluid and sodium intake as well as renal fluid and sodium output appear reduced compared with the preflight condition. In addition, influences of reduced energy intake may be more important for total body fluid content inflight than generally assumed. Decreases in plasma volume and observations of upper body edema formation inflight indicate, in addition, an increased extravasation as a result of the headward fluid shift in weightlessness. Current simulations models of microgravity for body fluid metabolism are valid for simulations of the central fluid shift occurring in microgravity. Since weightlessness appears to decrease central venous pressure and does not induce an increased renal fluid and sodium excretion, while simulations models have opposite effects, additional models to simulate adaptation of body fluid metabolism to weightlessness might be necessary.
近期太空任务的观测结果表明，失重并不会导致宇航员的利尿和排钠增加。相反，与飞行前状态相比，口服液体和钠的摄入量以及肾脏液体和钠的排出量似乎都减少了。此外，能量摄入减少对飞行中总体液含量的影响可能比通常认为的更为重要。血浆量的减少以及飞行中上身水肿形成的观察结果还表明，失重状态下头部方向的液体转移导致血管外渗增加。目前用于体液代谢的微重力模拟模型对于模拟微重力下发生的中心液体转移是有效的。由于失重似乎会降低中心静脉压，且不会导致肾脏液体和钠排泄增加，而模拟模型却有相反的效果，因此可能需要额外的模型来模拟体液代谢对失重的适应。
