How Daylight Saving Time affects your sleep and diet

夏令时如何影响你的睡眠和饮食

This annual time shift has long-lasting effects on health

这一每年一次的时间调整会对健康产生持久影响

As clocks spring forward in the northern hemisphere, many people will be looking forward to longer, sunnier evenings—a few groggy mornings is a price they’re probably willing to pay. 

随着北半球时钟进入夏令时（时钟拨快一小时），许多人都在期待更漫长、阳光更充足的夜晚——即便要忍受几天昏昏沉沉的早晨，他们或许也觉得值得。

But a growing body of research suggests that they ought to be more cautious. The arrival of Daylight Saving Time (DST) seems to have long-lasting negative effects on human health.

但越来越多的研究表明，人们应当更加谨慎。夏令时（简称 DST）的到来似乎会对人体健康产生长期的负面影响。

The human body clock, known as the circadian rhythm, lives in a region of the brain’s hypothalamus known as the suprachiasmatic nucleus (SCN). 

人体的生物钟，即昼夜节律，位于大脑下丘脑一个被称为视交叉上核（SCN）的区域。

It determines whether you feel awake or sleepy by regulating the production of melatonin, the sleepiness hormone, and cortisol, a stress hormone that promotes alertness. It is also essential for the timing of bodily functions, including the expression of genes and regulation of metabolism and mood.

它通过调节褪黑素（一种让人产生困意的激素）和皮质醇（一种促进警觉性的应激激素）的分泌，来决定我们是感到清醒还是困倦。生物钟对于调节身体机能的时间也至关重要，包括基因表达、新陈代谢和情绪调节。

What sets the body clock ticking is a person’s exposure to light, particularly the blue wavelengths that are more prevalent in the morning. Specialised cells in the retina send instructions to the SCN and, when the clock is set off correctly in the morning, sleep hormones appear at the right time in the evening and people wake up naturally at the right time the next day.

决定生物钟运转的是一个人暴露在光线下的情况，尤其是早晨更为常见的蓝光波长。视网膜中的特殊细胞会向视交叉上核发送指令。当早晨生物钟被正确设定时，睡眠激素会在晚上适时分泌，人们也会在第二天自然醒来。

Standard time, what some may think of as winter time, more closely aligns with the natural light-dark cycles of day and night. On standard time, people get more blue early-morning light, thus setting off their body clocks properly. 

标准时间，也就是一些人所说的冬令时，更贴近昼夜的自然明暗循环。在标准时间下，人们能接触到更多早晨的蓝光，从而正确设定生物钟。

Not only is there less of this morning light during DST, the extra hour of light in the evenings makes things worse by interfering with melatonin production—thus delaying the onset of sleep. All this adds up to a misalignment of sleep-and-wake rhythms during DST, and it also plays havoc with the release of cortisol, ghrelin (a hunger hormone) and leptin (the satiety hormone).

而在夏令时期间，早晨的蓝光不仅减少，晚上多出的一小时光照更会干扰褪黑素的分泌，从而延迟入睡时间。这一切都导致夏令时期间睡眠-觉醒节律失调，同时也会打乱皮质醇、饥饿素（一种饥饿激素）和瘦素（一种饱腹感激素）的分泌。

A study in the Journal of Health Economics in 2019 looked at people living on opposite sides of a time zone in America. On the late Sun side (in effect an hour behind the early Sun side), on average people were sleeping 19 minutes fewer every day during DST, were 11% more likely to be overweight and obese, and their wages were 3% lower. 

2019 年发表在《健康经济学杂志》上的一项研究调查了居住在美国一个时区东西两侧的人。在晚日照一侧（实际上比早日照一侧晚一小时），夏令时期间，人们平均每天少睡 19 分钟，超重和肥胖的可能性高出 11%，工资也低 3%。

Other studies show that the chronic effects are worse for teenagers, who are already biologically prone to being alert at night. They lose 32 minutes a night.

其他研究表明，对于本就容易在夜间保持清醒的青少年来说，夏令时的长期影响更为严重，他们每晚少睡 32 分钟。

The sudden shift to DST itself also brings short-term health and safety risks. One study showed that, in the morning after the time shift, participants lost about 40 minutes of sleep, on average. 

突然切换到夏令时本身也会带来短期的健康和安全风险。一项研究表明，在时间调整后的那个早晨，参与者平均少睡约 40 分钟。

Further problems include a spike in strokes (8%), heart attacks (24%), suicides (6%), and a slight increase in fatal traffic accidents. Moreover, researchers have noted an impact on episodes of depression, and studies in mice have tied DST to inflammatory bowel disease.

进一步的问题还包括中风（增加 8%）、心脏病发作（增加 24%）、自杀（增加 6%）以及致命交通事故略有增加。此外，研究人员还注意到，抑郁症的发作也受到了影响，而对小鼠的研究则将夏令时与炎症性肠病联系起来。

There are ways to reduce some of these health problems. Eva Winnebeck, a chronobiologist at the University of Surrey, says that sitting outside in the morning (without sunglasses) can reset the biological clock. 

有一些方法可以减少这些健康问题。萨里大学的生物节律学家伊娃·温内贝克表示，早晨坐在户外（不戴太阳镜）可以重置生物钟。

Avoiding the glare of screens late at night will also help, as will changing your home’s lighting to warmer hues in the evening to lessen the dampening effect of bright light on the production of melatonin. 

避免深夜盯着刺眼的屏幕也有帮助，晚上将家里的灯光调成暖色调，也能减轻强光对褪黑素分泌的抑制作用。

There is nothing to stop you from enjoying the long evenings, of course, whether you decide to do some gardening or play golf. But perhaps consider wearing orange-tinted glasses that filter out any blue light. You might look a little strange, but can you really put a price on a good night’s sleep?

当然，这并不妨碍你享受漫长的夜晚，无论你是打算做些园艺还是打高尔夫球。但或许可以考虑戴一副能过滤蓝光的橙色眼镜。你可能会看起来有点奇怪，但一夜安眠难道是能用钱买到的吗？