科学美国人60秒:登山者饮用甜菜汁-托福听力下载

　　科学美国人60秒中文翻译：

　　At 14,505 feet, Mount Whitney towers over California's Sierra Nevada range. 属加利福尼亚州内华达山脉的惠特尼山海拔14505英尺。

　　It's the tallest peak in the lower 48—which means it attracts thousands of weekend warriors every year—or make that weakened warriors. 惠特尼山是美国本土48州的最高峰—这座山每年会吸引成千上万名勇士周末前来这里挑战—但同时也造就了许多虚弱人士。

　　You see them staggering along the narrow, rocky trail, huffing for air, dizzy and exhausted from the low oxygen levels at high elevation. 你会看到这些攀登者在狭窄崎岖的山路上步履蹒跚，气喘吁吁，并且在高海拔低氧环境下筋疲力尽的样子。

　　And once they're sick? 但如果他们不舒服怎么办?

　　The best medicine is to go down. 最好的良药就是下山。

　　That's actually the only cure that works. 这是唯一有效的方法。

　　Svein Gaustad, a physiologist at the Norwegian University of Science and Technology. 挪威科技大学的生理学家斯威因·加斯特德这样说道。

　　He says previous studies suggest blood vessels tend to contract at high altitudes. 加斯特德表示先前的研究表明血管会在高海拔地区收缩。

　　Possibly because they need oxygen to relax—exactly what's in short supply on mountaintops. 可能因为血管需要氧气舒张—而在山顶时则会面临供氧不足的情况。

　　But there may be a dietary way to get more oxygen to your blood vessels:in the form of beet juice. 但是可以通过饮用甜菜汁这样的形式让更多的氧气进入你的血管。

　　The juice contains nitrate, which the body converts to nitricoxide, the compound that keeps arteries limber. 甜菜汁中含有硝酸盐，而人体可以将这种物质转化成一氧化氮从而保持动脉通畅。

　　Gaustad and his colleagues tested that theory during a trek in Nepal, at 12,000 feet. 加斯特德和他的同事们在海拔12000英尺的尼泊尔山进行远距离行走检测此种理论。

　　Eight volunteers alternately drank shots of regular beet juice, and another day, beet juice with the nitrates stripped out. 8名志愿者轮流饮用普通甜菜汁及去掉硝酸盐的甜菜汁。

　　A few hours later, the researchers measured blood flow and artery diameters with ultrasound. 几小时后，研究者们通过超声波测量血流以及动脉直径。

　　And they found that the regular beet juice did indeed restore blood vessels back to their low-elevation flexibility, whereas the nitrate-stripped juice did not. 结果他们发现，普通的甜菜汁确实能将血管恢复到在低海拔时的灵活性，而去掉硝酸盐的甜菜汁却没有这种效果。

　　The results are in the journal Nitric Oxide. 这项研究已经在《氧化氮》杂志上发表。

　　Gaustad says better vascular function has the potential to deliver more blood—and therefore more oxygen—to tired muscles. 加斯特德表示血管功能更好则代表会输送更多血液—进而为疲惫的肌肉输送更多氧气。

　　But they still don't know if that translates to better performance at altitude. 但是，他们仍不知晓是否着在高海拔处会有更好的效果。

　　And, he says, beets won't hurt, but they're no substitute for proper acclimatization. 而且他表示甜菜不会造成伤害，但是这种饮品不能作为适应环境的替代品。

　　If I had a bottle of beets around I would take it for sure. 如果身边有一瓶甜菜汁，我当然会喝掉。

　　But that won't bring you to Mount Everest just by drinking beetroot. 但是，仅仅靠饮用甜菜汁并不能助你登上珠穆朗玛峰之巅。

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