Leach C S, Cintrón N M, Krauhs J M
Biomedical Operations and Research Branch, National Aeronautics and Space Administration, Johnson Space Center, Houston, Texas 77058.
J Clin Pharmacol. 1991 Oct;31(10):921-7. doi: 10.1002/j.1552-4604.1991.tb03650.x.
Study of metabolic alterations that occur during space flight can provide insight into mechanisms of physiologic regulation. Results of medical experiments with astronauts reveal rapid loss of volume (2 L) from the legs and a transient early increase in left ventricular volume index. These findings indicate that, during space flight, fluid is redistributed from the legs toward the head. In about 2 days, total body water decreases 2 to 3%. Increased levels of plasma renin activity and antidiuretic hormone while blood sodium and plasma volume are reduced suggest that space flight-associated factors are influencing the regulatory systems. In addition to fluid and electrolyte loss. Skylab astronauts lost an estimated 0.3 kg of protein. Endocrine factors, including increased cortisol and thyroxine and decreased insulin, are favorable for protein catabolism. The body appears to adapt to weightlessness at some physiologic cost. Readaptation to Earth's gravity at landing becomes another physiologic challenge.
对太空飞行期间发生的代谢变化进行研究有助于深入了解生理调节机制。对宇航员进行医学实验的结果显示，腿部迅速流失2升体液，左心室容积指数短暂早期增加。这些发现表明，在太空飞行期间，体液从腿部重新分布到头部。大约两天内，全身水分减少2%至3%。血浆肾素活性和抗利尿激素水平升高，而血钠和血浆量减少，这表明与太空飞行相关的因素正在影响调节系统。除了体液和电解质流失外，“天空实验室”的宇航员估计还损失了0.3千克蛋白质。包括皮质醇和甲状腺素增加以及胰岛素减少在内的内分泌因素有利于蛋白质分解代谢。身体似乎以一定的生理代价适应失重状态。着陆时重新适应地球引力成为另一项生理挑战。
