Robinson E L, Fuller C A
Section of Neurobiology, Physiology and Behavior, University of California, Davis 95616-8519, USA.
Pflugers Arch. 2000;441(2-3 Suppl):R32-8. doi: 10.1007/s004240000329.
Gravity appears to alter thermoregulation through changes in both the regulated level of body temperature and the rhythmic organization of temperature regulation. Gravity has been hypothesized to have an associated metabolic cost. Increased resting energy expenditure and dietary intake have been observed in animals during centrifuge experiments at hypergravity. Thus far, only animals have shown a corresponding reduction in metabolism in microgravity. Altered heat loss has been proposed as a response to altered gravitational environments, but remains documented only as changes in skin temperature. Changes in circadian timing, including the body temperature rhythm, have been shown in both hypergravity and microgravity, and probably contribute to alterations in sleep and performance. Changes in body temperature regulation may result from circadian disturbance, from the direct or indirect actions of gravity on the regulated temperature, or from changes in thermoregulatory effectors (heat production and heat loss) due to altered gravitational load and convective changes. To date, however, we have little data on the underlying thermoregulatory changes in altered gravity, and thus the precise mechanisms by which gravity alters temperature regulation remain largely unknown.
重力似乎通过改变体温的调节水平和温度调节的节律性组织来改变体温调节。据推测，重力存在相关的代谢成本。在动物进行超重力离心实验期间，观察到静息能量消耗和饮食摄入量增加。到目前为止，只有动物在微重力环境下表现出相应的代谢降低。有人提出，热量散失的改变是对重力环境改变的一种反应，但目前仅记录为皮肤温度的变化。在超重力和微重力环境下均已观察到昼夜节律的变化，包括体温节律，这可能导致睡眠和工作表现的改变。体温调节的变化可能源于昼夜节律紊乱、重力对调节温度的直接或间接作用，或者由于重力负荷改变和对流变化导致的体温调节效应器（产热和散热）的变化。然而，迄今为止，我们关于重力改变时潜在体温调节变化的数据很少，因此重力改变温度调节的精确机制在很大程度上仍然未知。
