因为全球变暖，人们每年少睡了44小时！为什么温度高睡不着？丨夜听双语

气温逐渐升高，你有没有被热得睡不着觉呢？

最近，丹麦哥本哈根大学的一项研究显示，全球变暖令夜间温度不断升高，世界各地的人们平均每人每年丢失44小时睡眠。研究者称，高温会让人们更晚入睡并且醒得更早。

In a study published May 20th in the journal One Earth, investigators report that increasing ambient temperatures negatively impact human sleep around the globe. 5月20日发表在《一个地球》期刊上的一项研究表明，环境温度的上升给全球各地人们的睡眠带来了负面影响。

To conduct this research, the investigators used anonymized global sleep data collected from accelerometer-based sleep-tracking wristbands. The data included 7 million nightly sleep records from more than 47,000 adults across 68 countries spanning all continents except for Antarctica. 研究人员使用了来自睡眠追踪腕带的匿名全球睡眠数据。这些数据包括700万份夜间睡眠记录，来自68个国家的47000多名成年人，涵盖了除南极洲外的所有大洲。

研究预测，到2099年，全球变暖可能会导致每人每年睡眠时长减少50至58小时。

The team says their findings suggest that by the year 2099, suboptimal temperatures may erode 50 to 58 hours of sleep per person per year. suboptimal /ˌsʌbˈɒptɪməl/：次最优的；未达最高标准的 erode /ɪˈrəʊd/：侵蚀

此外，研究还发现，高温会对低收入国家的居民、老年人和女性的睡眠时长造成更大的影响。

In addition, they found that the temperature effect on sleep loss is substantially larger for residents from lower income countries as well as in older adults and females.

为什么高温会影响睡眠

我们的睡眠质量与身体内部的“核心体温”（core temperature）有关。

白天，人体的平均体温为37摄氏度。但是在晚上六到七个小时的睡眠过程中，核心体温会下降1.2摄氏度。核心体温的下降速度越快，你就越快入睡。

Our bodies are highly adapted to maintain a stable core body temperature. Every night they shed heat from our core into the surrounding environment by dilating our blood vessels and increasing blood flow to our hands and feet. 我们的身体能够极好地维持稳定的核心体温。每天晚上，我们的身体会扩张血管、增加流向手脚的血液，从核心向周围环境散发热量。 In order for our bodies to transfer heat, the surrounding environment needs to be cooler than we are. 为了保证散热过程的顺利进行，周围的环境需要比我们自身的温度低。

据法国《新观察家》周刊网站，睡眠最理想的环境温度为22℃~23℃。高于24℃，睡眠会变浅，翻身次数会增多；低于18℃，人不容易熟睡，深度睡眠时长也会缩短。

怎样才能睡得好

睡眠时间不足可能会导致我们得不到足够的深度睡眠（deep sleep），增加患某些疾病和慢性疾病的风险。

An insufficient amount of sleep hours may mean you're not getting enough deep sleep, and sleep deprivation can increase your risk for certain diseases and chronic conditions.

快节奏的生活使得每天保证8个小时的睡眠似乎并不现实。偶尔熬夜就罢了，保证睡眠质量还是很重要的，这些睡眠质量小贴士，你了解吗？

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Avoid caffeine for four to six hours before bedtime

睡前4-6小时避免摄入咖啡因

As any coffee lover knows, caffeine is a stimulant that can keep you awake. So avoid caffeine. For four to six hours before bedtime. Similarly, smokers should refrain from using tobacco products too close to bedtime. 咖啡因是一种能让你保持清醒的兴奋剂，所以在睡前4-6小时应避免摄入咖啡因。同样，吸烟者应避免在临睡前使用烟草产品。

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Turn Your Bedroom into a Sleep-Inducing Environment

布置一个“睡眠友好型”卧室

Use heavy curtains, blackout shades, or an eye mask to block light. Keep the temperature comfortably cool and the room well ventilated. And make sure your bedroom is equipped with a comfortable mattress and pillows. 使用厚窗帘、遮光罩或眼罩来阻挡光线。保持室温舒适且通风良好。使用舒适的床垫和枕头。

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Establish a Soothing Pre-Sleep Routine

做一些放松的睡前活动

Ease the transition from wake time to sleep time with a period of relaxing activities an hour or so before bed. Take a bath (the rise, then fall in body temperature promotes drowsiness), read a book or watch television. 通过睡前一个小时左右的放松活动帮助自己过渡到适合睡觉的状态。比如，你可以洗个澡（这个过程中体温先上升，后下降，会让你昏昏欲睡），读书或者看看电视。

这里是中国日报双语新闻夜听双语，我是双语君。

晚安。

编辑：左卓

实习生：房晓玥

来源：WebMD, Science Daily, Healthy Sleep