美国有线新闻 CNN 零重力可能导致宇航员血液倒流

零重力可能导致宇航员血液倒流

Here on Earth where most of us live, we spend about a third of everyday lying down sleeping and two-thirds standing¹ or sitting in an upright position.

That's not really how it goes in space when people are weightless and the zero gravity environment causes more fluid to shift to the head. Faces get puffy, legs lose volume and appear to be smaller. Many astronauts have c?omplained of eye and back problems after coming back down to Earth and its gravity.

And now scientists say they've discovered some new risks with long term space flight. A study published recently in JAMA Network Open, a medical journal, examined 11 healthy astronauts who'd been on the International Space Station for six months. Eight of the them had unusual characteristics observed in their blood. F?or instance, six of the astronauts had either stagnant² or reverse blood flow from their heads.

The lead author of the study says he doesn't know if that's actually harmful. The blood's still leaving the head from other pathways, so flowing backwards³ through a jugular⁴ vein⁵ may not be dangerous. But he says it does show a change in how blood moves through the body while in space.

Another issue the study found was blood clots⁷. One astronaut had one. Another showed signs of a partial blood clot⁶. That is potentially harmful as the clots can block the flow of blood to the lungs. The astronaut who had one was treated for the rest of the spaceflight and made it home safely.

What does all this mean? Well, one researcher says these issues have probably been occurring since humans first ventured into space and that they would likely resolve themselves when astronauts came back down to Earth. Knowing about them now gives doctors something else to monitor when people leave our atmosphere.

1 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

2 stagnant   

adj.不流动的，停滞的，不景气的

参考例句：

• Due to low investment,industrial output has remained stagnant.由于投资少，工业生产一直停滞不前。
• Their national economy is stagnant.他们的国家经济停滞不前。

3 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。

4 jugular   

n.颈静脉

参考例句：

• He always goes for the jugular.他总是直奔要害而去。
• Bilateral internal jugular vein stenting is also a rare procedure.两侧内颈静脉支架置放术也是少见的技术。

5 vein   

n.血管，静脉；叶脉，纹理；情绪；vt.使成脉络

参考例句：

• The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
• The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。

6 clot   

n.凝块；v.使凝成块

参考例句：

• Platelets are one of the components required to make blood clot.血小板是血液凝固的必须成分之一。
• The patient's blood refused to clot.病人的血液无法凝结。

7 clots   

n.凝块( clot的名词复数 )；血块；蠢人；傻瓜v.凝固( clot的第三人称单数 )

参考例句：

• When you cut yourself, blood clots and forms a scab. 你割破了，血会凝固、结痂。 来自《简明英汉词典》
• Milk clots when it turns sour. 奶变酸就凝块。 来自《现代英汉综合大词典》