(单词翻译:单击)
听力文本
From VOA Learning English, this is the Health Report.
Why do we need sleep?
Is bedtime just a time for dreaming? Do our brains turn off for the night? What if I told you that scientists recently discovered that our brains may be just as busy at night as they are during the day?
While we sleep, our brains are doing much more than getting ready for the next day. Researchers at the University of Rochester found that the brain may be busy cleaning house -- cleaning out harmful waste materials.
As with many studies, the researchers turned to mice for help. They studied mice that had colored dye injected into their brains. They observed the mice brains as they slept and when they were awake. The researchers say they saw that the brains of sleeping mice were hard at work.
Working Double Duty
Dr. Maiken Nedergaard led the study. The brain expert says our brains perform two very different jobs. It seems they have daytime jobs. Later they "moonlight" at a nighttime job.
"Moonlighting" is working a nighttime job in addition to a day job. And this study says that is what our brains seem to be doing – working an extra job at night without additional pay for overtime.
"When we are awake, the brain cells are working very hard at processing all the information about our surroundings. Whereas when we are asleep, they work very, very hard at removing all the waste that builds up when we are awake."
The researchers say that the waste material includes poisons, or toxins, responsible for brain disorders such as Alzheimer's disease.
They also found that during sleep, the brain's cells shrink, or become smaller. This shrinking permits waste to be removed more effectively.
Dr. Nedergaard says these toxins end up in the liver. There, they are broken down and then removed from the body.
"So our study suggests we need to sleep because we have a macroscopic cleaning system that removes many of the toxic waste products from the brain."
The brain's cleaning system could only be studied with new imaging technologies. The test animal must be alive in order to see for this brain process to be seen as it happens.
Dr. Nedergaard says the next step is to look for the process in human brains. She said the results demonstrate just how important sleep is to health and fighting disease. The research may also one day lead to treatments to prevent or help fight neurological disorders.
7 Tips for Better Sleeping
Do you have trouble sleeping? Not being able to sleep is called insomnia. According to the United States National Sleep Foundation, here are some tips for a good night's sleep:
Go to bed about the same time each night, even on weekends. This helps to "set" your body's "sleep clock."
Exercise every day.
Have a calm, relaxing bedtime routine – Take a warm bath or drink a hot cup of tea.
Try not to take long naps during the day. Periods of sleep during the daytime can interfere with sleep at night.
Make sure you have a pleasant environment where you sleep. For most people, a cool, quiet and dark room is best for sleeping.
Avoid using television, computers and other electronic screens before bedtime.
Also avoid alcohol, cigarettes and heavy meals before bedtime.
And from VOA Learning English, that's the Health Report. I'm Anna Matteo.
Do you suffer from insomnia? Do you have more suggestions for a good night's sleep. Let us know in our comment section.
文本来自51voa，译文属可可原创，仅供学习交流使用，未经许可请勿转载
词汇解释
1.dye n. 染料；染色 vt. 染；把…染上颜色 vi. 被染色
The women prepared, spun, and dyed the wool.
妇女们将羊毛预备、纺线并染色。
2.Moonlighting n. 夜间活动；夜袭；（尤指夜间）从事第二职业
I have to do a moonlighting job, so that I can afford to rent an apartment near to my company.
我不得不做一份兼职的工作，这样我才能租得起靠近公司的一间公寓。
3.insomnia n. 失眠症，失眠
If you have insomnia, try my simple cure.
如果你有失眠症，试试我的简单疗法。
内容解析
1.Whereas when we are asleep, they work very, very hard at removing all the waste that builds up when we are awake.
build up (交通)阻塞，(交通)越来越拥挤，(车辆)拥挤起来；(用砖等)堵塞(门、窗等)：
During the summer holidays,traffic builds up along the roads to the coast.
每到暑假，在去海滨的路上车辆就拥挤起来。
The doorway in the west side was built up by the neighbour's house.
西面的门口被邻居的房子阻塞了。
参考译文
美国之音慢速英语健康报道。
人们为何需要睡眠？
床上时光只是为了做梦么？我们的大脑在夜晚会停止工作吗？我要告诉大家的是，科学家最近发现人类大脑在晚上的时候可能像在白天一样忙碌。
我们睡觉时，大脑要做更多工作来为第二天做准备，罗彻斯特大学的研究者发现，大脑可能要忙着清理房间，清理掉有害的垃圾。
研究者在很多研究中都向小白鼠求助，他们研究大脑染色的小白鼠，他们观察小白鼠的在睡觉和清醒时的大脑，研究者称看到睡眠中小白鼠的大脑也在忙碌工作。
梅肯·麦耿聂德卡是这项研究的负责人，这位大脑专家说，我们的大脑做两种非常不同的工作。看来大脑有白天的工作，然后在晚上做“兼职”工作。
“兼职”是在白天工作后在夜晚工作，这项研究称看来这就是我们大脑在忙碌的事情，在晚上做没有报酬的加班工作。
“我们清醒时，大脑细胞非常忙碌地够工作，处理周围的所有信息。我们睡觉时，他们也要非常努力地清除掉清醒时积累的全部垃圾。”
研究者称这些垃圾包括能导致老年痴呆症等疾病的毒素。
他们还发现在睡眠期间，大脑的细胞会缩小，这就让垃圾能更有效地清理出去。
麦耿聂德卡博士说这种毒素最后被清理到肝脏中，毒素在那里被弄碎，然后排出体外。
“我们的研究表明，我们之所以需要睡眠，是因为我们有着非常微观的清理系统，这个系统能清除掉大脑中产生的很多垃圾。”
可以通过新的成像技术来研究大脑的清理系统，实验中的动物必须保持清醒，这样就能看到这个过程发生时的情况。
麦耿聂德卡博士说下一步是看人脑中的这一过程，她说结果表明睡眠对健康和对抗疾病的重要性，这项研究可能有一天促成预防或治疗神经疾病的疗法。
你有睡眠问题吗？不能入睡叫做失眠。美国国家睡眠基金会提供了几个好建议来帮你晚上睡个好觉。
每天晚上都在相同的时间去睡觉，即使是在周末，这就帮助设定身体的“睡眠时钟。”
每天锻炼身体。
睡觉前要保持平静和放松，可以洗个热水澡或喝杯热茶。
白天不要小睡太久，白天睡觉太久会影响晚上的睡眠。
确保睡眠环境良好，对大多数人来说，安静和黑暗的房间最有助于睡眠。
不要在睡前使用电视、电脑等电子屏幕设备。
不要在睡前喝酒、吸烟和吃太多。
这就是美国之音健康报道，我是安娜·马特奥。
你有失眠症吗？你有晚上睡好觉的更多建议吗？在评论版块告诉我们。
