Screen Time Can Mess with the Body

石斯琳

Reading on an iPad in the evening can make it hard for the body to fall asleep. For a good nights sleep， here is some expert advice： Turn off， turn in and drop off.

晚上睡觉前看苹果平板电脑会更加难以入睡。为了拥有一个高质量的睡眠，这里提供一些专业意见：关掉苹果平板电脑，放进抽屉，舒服入睡。

Anyone who does the opposite—say， turning on an iPad or other similar electronic reader in bed—may have a harder time both dropping off to sleep and shaking that groggy1 feeling the next morning. Thats the conclusion of a new study.

有的人所做的恰恰相反，例如在床上用着苹果平板电脑或者其他电子阅读设备。新研究结论表明，这些（夜晚入睡前还用电子设备的）人可能更加难以入睡，或者隔天整一个早上昏昏沉沉的感觉都会挥之不去。

Sleep experts at Brigham and Womens Hospital in Boston found that the light from a tablet2 computer upsets the bodys internal clock. They reported their findings in the Proceedings of the National Academy of Sciences. And that can create real health and safety risks， the researchers say. Reading a printed book did not have the same effect. An internal “clock” helps regulate3 when we eat， sleep and wake. Exposure to the light of day and darkness of night keeps its timing set to a roughly 24-hour cycle.

來自波士顿布里格姆女子医院的睡眠专家们发现平板电脑发射出的光线会扰乱人体内的生物钟。专家们在美国《国家科学院学报》上发表了他们的研究报告。研究结果显示，这种扰乱会造成严重的健康安全问题。然而睡前阅读纸质书籍并不会造成危害。当我们进食、入睡和醒来的时候，体内的生物钟会对我们的身体进行调节。白天的光线和夜间的黑暗让体内的生物钟自动形成大致24小时的循环模式。

For instance， starting about two hours before bedtime， our brains start to produce a hormone called melatonin4. It signals5 our internal clock that darkness has fallen. It also prepares the body for sleep. Scientists long have known that light at night can disrupt6 that internal clock. And it does so by suppressing7 melatonin.

例如，在入睡前的两个小时，我们的大脑就会开始自动分泌一种叫做褪黑激素的荷尔蒙。这种激素向我们体内的生物钟发出黑夜降临的信号，也为身体入睡做好准备。科学家很早就得出了夜晚的人照光线会扰乱人体内生物钟，并抑制褪黑激素分泌的结论。

Electronic devices with lit screens are now hugely popular. They have added another source of artificial light at night. The new study looked specifically8 at the iPad. For their new study， the researchers recruited six men and six women， all in their mid 20s. Over two weeks， each spent four hours reading each evening before a 10 p.m. bedtime. The volunteers read on an iPad for five nights in a row. On another five consecutive9 evenings they read a printed book. The researchers noted how long it took the volunteers to fall asleep， how long they spent asleep and how long they remained in each stage of sleep. The experts also took blood samples to measure melatonin levels. People took nearly 10 minutes longer to fall asleep， on average， after reading on the iPads. There was no difference in hours spent sleeping after reading from either the iPad or a printed book. But how volunteers felt the next day did differ.

带有照明屏幕的电子设备现在是炙手可热的产品。它们为夜晚人造光增添了另一种新形式。新研究把关注重点放在了苹果平板电脑上。在新研究中，研究者招募了六男六女共12个志愿者，年龄均在25岁左右。在长达两个星期的研究过程中，每个志愿者在每天晚上10点（睡觉的时间点）之前花四个小时阅读。这十二个志愿者连续五个晚上用苹果平板电脑阅读，另外五个晚上阅读纸质书籍。研究者记录下研究对象入睡需花费的时间，睡眠时长，以及每个阶段的睡眠持续时间。专家还采集了血样以测量褪黑素值。（结果显示）那些睡前用苹果平板电脑的人比不用的人平均需多花十分钟才能入睡。然而不管是用苹果平板电脑阅读还是看紙质书籍，睡眠时长都没有差别。差别在于志愿者隔天的精神状况。

“Our most surprising10 finding was that individuals using the e-reader would be more tired and take longer to become alert the next morning，” says sleep researcher Anne-Marie Chang.

睡眠研究专家安娜-玛丽·张表示：“最出人意料的发现是，用电子设备阅读者第二天早上会更加疲惫，需要花更多的时间清醒。”

Regularly getting too little sleep can pose important health risks. For instance， studies have shown that it can up the risk of everything from obesity， diabetes11 and depression to car accidents.

经常性的睡眠不足会造成严重的健康问题。例如，研究表明睡眠不足可能引发诸如肥胖、糖尿病、抑郁甚至车祸等问题。

Notes：

1. groggy adj. 头晕的；昏昏沉沉的

2. tablet n. 平板电脑

3. regulate vt. 调整

4. melatonin n. 褪黑激素

5. signal v. （发信号）通知、表示

6. disrupt vt. 破坏；使瓦解；使分裂

7. suppress vt. 镇压；压制

8. specifically adv. 特别地；明确地；具体地

9. consecutive adj. 连续的；连贯的

10. surprising adj. 令人惊讶的，出人意料的

11. diabetes n. 糖尿病；多尿症