特朗普总统正大力推动美国参议院使夏令时永久化，这样一来，包括高尔夫球员在内的人们可以更晚地留在球场上，但这可能并非多明智之举。来自加拿大的新研究表明，即使美国人民能获得更多的傍晚日照时间，永久夏令时的不良健康影响可能会超过其益处。周一发表在《加拿大医学协会期刊》上的一篇论文回顾了关于永久夏令时（pDST）健康影响的证据，当时多个加拿大司法管辖区正打算停止调整时钟。
President Trump is pushing hard for the US Senate to make daylight saving time permanent so, among other things, golfers can stay on the course longer, but it may not be such a bright idea. New research out of Canada suggests that, even if Americans would get an extra hour of daylight in the evening, the ill health effects of permanent daylight saving time could outweigh the benefits. A paper published in the Canadian Medical Association Journal on Monday reviewed evidence on the health effects of permanent daylight saving time (pDST) as several Canadian jurisdictions move to stop changing their clocks.
该论文指出，另一种方法——即采用永久标准时间（pST）——实际上对人们的健康更有利。抱歉了，夜猫子们和加班后的社交达人们，但科学事实并不支持你们这一立场。
It finds that the opposite approach - adoption of permanent standard time (pST) - would actually be better for people’s health. Sorry, night owls and after-work social butterflies, but the science simply isn’t with you on this one.
论文作者指出：“永久夏令时保留了更晚的傍晚光线，这有助于上下班通勤、休闲娱乐、社会参与和某些经济活动，但它也延长了冬季早晨的黑暗。”早晨长时间的黑暗与人体内部机制以及光线在调节生物钟中的重要作用并不完全相符。当然，没人愿意在天黑回家，但我们确实需要早晨的光线来正常地开始一天。作者解释道，人们的生物钟实际上比一天稍长——24.2小时，因此我们依赖自然阳光来与周围世界保持同步。
“Permanent DST preserves later evening light that may facilitate commuting, recreation, social participation, and some economic activity, but it also prolongs darkness on winter mornings,” the authors note. Prolonged morning darkness doesn't really jibe with the inner workings of the human body and light’s essential role in regulating the circadian rhythm. Sure, no one wants to drive home from work in the dark, but we really need morning light to get us functioning properly. Our circadian rhythms, the authors explain, actually run on a slightly longer schedule than a full day - 24.2 hours. For that reason, we rely on natural sunlight to keep us synchronized with the world around us.
作者还指出，早晨的光线尤其重要，因为它能启动生物钟，唤醒我们并让我们开始活动。而傍晚的光线则会延迟生物钟，干扰我们对“社会时间”的感知，使我们更难入睡以及清晨起床后精力充沛。
Morning light is some of the most important, the authors note, because it jump starts that rhythm, wakes us up and gets us moving. Evening light, on the other hand, delays the circadian rhythm, messing with our sense of “social time” and making it tougher to get to sleep and wake up rested in the morning.
作者们指出，晚间光线的影响会体现在睡眠、情绪、教育和工作效率上，我们甚至不需要借助全民夏令时的政策就能观察到这些关联——只需看时区划分即可。从美国或加拿大的东部向西部移动，你会发现同一个时区内日出和日落时间存在相当大的差异——有时甚至相差超过一个小时的钟表时间。在加拿大研究引用的一项研究中，位于美国时区西部的居民（太阳落山较晚的地方）每周睡眠时间大约少了一个小时。
The effects of later evening light can show up in sleep, mood, education, and work productivity, the authors noted, and we don’t even need pDST to see some of those associations - we can just look at time zones. Move from east to west in the US or Canada and you’ll get some considerable differences in when the sun rises and sets in a particular time zone - in some cases, sunrise and sunset can differ by more than an hour of clock time across a single time zone. In one study cited by the Canadian analysis, residents on the western side of US time zones, where the sun sets later, got around an hour less sleep a week.
该研究还估计，每额外获得一小时的睡眠与长期收入约提高5%相关。正如该团队指出的那样，德国的一项研究也得出了类似结论。另一项研究发现，位于美国时区西端的工人工作小时数也更少。在教育方面，一项佛罗里达州的研究发现，上学前多一个小时的日光与更高的数学和阅读成绩相关，“其 magnitude 相当于有意义的班级人数减少”。
The study also estimated that an additional hour of sleep per week was associated with around 5 percent higher long-term earnings. Similar results turned up in a German study, the team noted. Another study found that workers on the western end of US time zones ended up working fewer hours, too. On the educational front, an extra hour of sunlight before school was associated with higher math and reading scores in a Florida study “comparable in magnitude to meaningful class-size reductions.”
“取消双年钟表调整可能消除持续几周的过渡伤害，但永久性时间政策的健康影响可能是慢性的，”作者们指出。“健康证据的主导观点支持永久标准时间，这符合全球睡眠和生物钟学会的推荐。”这并不是第一次有研究得出这样的结论。2024年，英国的睡眠科学家们也得出了几乎相同的结论，这促使他们建议永久取消夏令时，转而采用格林威治标准时间。
“Ending biannual clock adjustments may eliminate transition harms that last a few weeks, but the health effects of permanent time are likely to be chronic,” the authors noted. “The preponderance of health evidence favors pST, which would align with the recommendations of sleep and chronobiology societies worldwide.”This isn’t the first time researchers have concluded such. British sleep scientists concluded much the same in 2024, which led to their recommendation to permanently kill DST in favor of a permanent shift to Greenwich Mean Time.
尽管如此，这并没有阻止美国继续推进永久夏令时的计划。参议院在2022年通过了一项将夏令时写入法律的措施，但众议院从未对此采取行动。
That isn’t stopping the US from plowing ahead with plans for pDST, though. The Senate passed a measure to enshrine DST in 2022, but the House never acted on it.
这一次，众议院通过了自己的法案来实施永久夏令时，但参议院却在犹豫不决，这导致特朗普总统走出了极端举措，在社交媒体上公布了一位反对该法案的共和党参议员汤姆·科顿（R-AR）的个人手机号码。科顿在特朗普公布他的个人信息后，在X平台上发文解释道：“没人喜欢改钟，包括我在内，但国会之前多次通过永久夏令时法案，然而一旦美国人们体验到冬天日出异常晚的情景后，就每次推翻它。”
This time around, the House has passed its own bill to enact pDST, but the Senate is dithering, leading President Trump to go so far as to post the personal cellphone number of one Republican holdout on social media, Senator Tom Cotton (R-AR), who is opposed to the measure. “No one likes changing the clock, me included, but Congress has enacted permanent Daylight Savings Time multiple times before and repealed it each time once Americans experienced absurdly late sunrises in the winter,” Cotton explained in a post on X following Trump’s doxxing.
他的观点是正确的：美国曾两次实施永久夏令时——一次是在第二次世界大战期间，战后废除了；另一次是在1973年作为节能措施。1974年，国会在公众对冬季早上天黑的强烈不满下缩短了这项试验。正如加拿大的报纸所指出的那样，美国并不是唯一尝试但失败实施永久夏令时的国家。俄罗斯在2011年采用永久夏令时，2014年又废除了。
He’s right, too: The US has twice enacted pDST - once during World War II, which ended after the war, and again in 1973 as an energy saving measure. Congress curtailed the experiment later in 1974 following public backlash over dark winter mornings. The US isn’t alone in trying and failing at enacting pDST, either, as the Canadian paper points out. Russia adopted pDST in 2011 and reversed it in 2014.
智利也尝试过并随后推翻了它。在这些案例中，推翻决定的原因各不相同，但涉及到的问题包括冬季早上天黑、睡眠和生物钟紊乱、安全问题以及公众的不满。尽管面临政治阻力和科学证据表明这是个坏主意，但美国政府最新尝试实施永久夏令时的成功与否尚不得而知，不过研究人员似乎并不希望它成功：他们指出，如果美国做出这样的改变，加拿大可能会面临追赶的压力。说到底，我们或许都更好地接受两次钟表调整和短期的睡眠紊乱。
Chile tried and reversed it as well. In those cases, the reasons for reversing course varied, but concerns included dark winter mornings, disrupted sleep and body clocks, safety, and public dissatisfaction. It’s unclear whether the US government’s latest attempt at enacting pDST will succeed despite political resistance and scientific evidence that it’s a bad idea, but the researchers sure seem to hope not: They note that, if the US makes such a change, Canada will likely be pressured to conform. At the end of the day, we might all be better off just dealing with a couple of clock changes and some short-term sleep disruption. ®