为什么要在晚上限制人造光

为什么要在晚上限制人造光

It's incredibly hard to sleep when light seeps through your curtains or your phone glows from the bedside table. But more and more research is finding that artificial light may be more than annoying. It can be seriously unhealthy, too.

当光线透过窗帘或手机从床头柜发出亮光时，你很难入睡。但越来越多的研究发现，人造光可能不仅令人讨厌，它也可能是严重不健康的。

You should seek out true darkness for better sleep. (Photo: Emiliano Rodriguez/Shutterstock)

The natural 24-hour cycle of daylight and darkness keeps our circadian biological rhythms in alignment. When those rhythms get out of whack, studies have shown a potential link to health issues ranging from insomnia to breast cancer. One of the major culprits may be melatonin, the main hormone that controls sleep and wake cycles. Light at night suppresses the secretion of melatonin, and a lack of melatonin has been linked to diabetes, obesity, heart disease and other health issues.

自然的昼夜循环使我们的昼夜生物节律保持一致。当这些节律不正常时，研究表明，它们可能与从失眠到乳腺癌等一系列健康问题有关。其中一个主要的罪魁祸首可能是褪黑激素，它是控制睡眠和觉醒周期的主要激素。夜晚的光线会抑制褪黑激素的分泌，而缺乏褪黑激素会导致糖尿病、肥胖、心脏病和其他健康问题。

Most recently, an international team of researchers analyzed data on the impact of light pollution on melatonin formation in humans and vertebrates and found that even low levels of urban skyglow can suppress production. They looked at hundreds of studies, looking for evidence of how light affects melatonin production — and it doesn't take much.

最近，一个国际研究团队分析了光污染对人类和脊椎动物褪黑激素形成影响的数据，发现即使是低水平的城市天光也会抑制褪黑激素的产生。他们研究了数百项研究，寻找光线如何影响褪黑激素产生的证据——而且不需要太多。

To get an idea of the impact, the researchers spelled out some variables. The skyglow of a city, a form of light pollution, can reach illuminances of up to 0.1 lux, and outdoor lighting can reach about 150 lux, according to a press release from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, which was part of the bigger team. But the thresholds for various creatures isn't that high: in fish the threshold is 0.01 lux, in rodents it's 0.03 lux and in sensitive humans, it's about 6 lux. Their results were published in the journal Sustainability.

为了了解影响，研究人员列出了一些变量。根据莱布尼茨淡水生态与内陆渔业研究所发布的新闻稿，城市的天光(光污染的一种形式)可以达到0.1勒克斯的照度，户外照明可以达到150勒克斯。但各种生物的阈值并没有那么高:鱼类的阈值是0.01勒克斯，啮齿动物是0.03勒克斯，而敏感的人类大约是6勒克斯。他们的研究结果发表在《可持续性》杂志上。

Cancer epidemiologist Richard Stevens from the University of Connecticut School of Medicine is a pioneer in the field, having studied the subject for 25 years. Stevens, who talks about his work , is credited as the first to hypothesize that the increased use of artificial light at night may be linked to the higher risk of breast cancer.

康涅狄格大学医学院的癌症流行病学家理查德·史蒂文斯是这一领域的先驱，他研究这一课题已有25年。史蒂文斯谈到了他的工作，他被认为是第一个提出假设的人，该假设认为夜间人工照明的增加可能与乳腺癌的高风险有关。

In a opinion paper published in the journal Philosophical Transactions B, Stevens posed the question: "Electric light, particularly at night, disrupts human circadian rhythmicity: Is that a problem?"

在《哲学学报B》发表的一篇观点论文中，史蒂文斯提出了这样一个问题:“电灯，尤其是在晚上，会打乱人类的昼夜节律:这是个问题吗?”

Stevens looked at the link between artificial light at night and its potential short-term and long-term impact on health. He points out that studies point to the importance of sleep at night, but now we should focus on the importance of darkness at night.

史蒂文斯研究了夜间人造光与其对健康的潜在短期和长期影响之间的联系。他指出，研究指出了晚上睡觉的重要性，但现在我们应该关注夜晚黑暗的重要性。

"The point of emphasis to all this is that while sleep is deeply important to well-being, so too is exposure at night to dark," he writes. "The importance of sleep has finally entered mainstream thinking and practice; however, the importance of dark is still greatly underappreciated."

他写道:“所有这些的重点是，虽然睡眠对健康非常重要，但晚上暴露在黑暗中也同样重要。”“睡眠的重要性终于进入了主流思想和实践;然而，黑暗的重要性仍然被大大低估了。”

Stevens points to evidence that has linked ambient light in the bedroom at night and the risk of depression and obesity, as well as many studies that have examined a similar connection with breast cancer. If those associations are causal, he says, there would be "obvious and easy interventions."

史蒂文斯指出，有证据表明，卧室夜晚的环境光线与抑郁和肥胖的风险有关，还有许多研究也证实了这一点。他说，如果这些联系是因果关系，就会有“明显而容易的干预”。

He suggests blackout shades and eliminating all light sources in the bedroom, no matter how small. If you need a night light, he says a dim red light would cause the least disruption to your body's circadian system.

他建议用遮光罩，把卧室里所有的光源都关掉，不管光源有多小。他说，如果你需要夜间照明，微弱的红光对你身体的昼夜节律系统的干扰最小。