為什么要在晚上限制人造光

為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.

當光線透過窗簾或手機從床頭柜發(fā)出亮光時，你很難入睡。但越來越多的研究發(fā)現(xiàn)，人造光可能不僅令人討厭，它也可能是嚴重不健康的。

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.

自然的晝夜循環(huán)使我們的晝夜生物節(jié)律保持一致。當這些節(jié)律不正常時，研究表明，它們可能與從失眠到乳腺癌等一系列健康問題有關。其中一個主要的罪魁禍首可能是褪黑激素，它是控制睡眠和覺醒周期的主要激素。夜晚的光線會抑制褪黑激素的分泌，而缺乏褪黑激素會導致糖尿病、肥胖、心臟病和其他健康問題。

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，一個國際研究團隊分析了光污染對人類和脊椎動物褪黑激素形成影響的數(shù)據(jù)，發(fā)現(xiàn)即使是低水平的城市天光也會抑制褪黑激素的產生。他們研究了數(shù)百項研究，尋找光線如何影響褪黑激素產生的證據(jù)——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.

為了了解影響，研究人員列出了一些變量。根據(jù)萊布尼茨淡水生態(tài)與內陸漁業(yè)研究所發(fā)布的新聞稿，城市的天光(光污染的一種形式)可以達到0.1勒克斯的照度，戶外照明可以達到150勒克斯。但各種生物的閾值并沒有那么高:魚類的閾值是0.01勒克斯，嚙齒動物是0.03勒克斯，而敏感的人類大約是6勒克斯。他們的研究結果發(fā)表在《可持續(xù)性》雜志上。

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.

康涅狄格大學醫(yī)學院的癌癥流行病學家理查德·史蒂文斯是這一領域的先驅，他研究這一課題已有25年。史蒂文斯談到了他的工作，他被認為是第一個提出假設的人，該假設認為夜間人工照明的增加可能與乳腺癌的高風險有關。

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《哲學學報B》發(fā)表的一篇觀點論文中，史蒂文斯提出了這樣一個問題:“電燈，尤其是在晚上，會打亂人類的晝夜節(jié)律:這是個問題嗎?”

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.

史蒂文斯研究了夜間人造光與其對健康的潛在短期和長期影響之間的聯(lián)系。他指出，研究指出了晚上睡覺的重要性，但現(xiàn)在我們應該關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."

他寫道:“所有這些的重點是，雖然睡眠對健康非常重要，但晚上暴露在黑暗中也同樣重要。”“睡眠的重要性終于進入了主流思想和實踐;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，有證據(jù)表明，臥室夜晚的環(huán)境光線與抑郁和肥胖的風險有關，還有許多研究也證實了這一點。他說，如果這些聯(lián)系是因果關系，就會有“明顯而容易的干預”。

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.

他建議用遮光罩，把臥室里所有的光源都關掉，不管光源有多小。他說，如果你需要夜間照明，微弱的紅光對你身體的晝夜節(jié)律系統(tǒng)的干擾最小。