It's a myth that DST was instituted to help farmers. And so daylight saving time was abolished until the next war brought it back into vogue. Related: 5 crazy chapters in the history of daylight saving time. After the war, a free-for-all system in which U. That federal law meant that any state observing DST — and they didn't have to jump on the DST bandwagon — had to follow a uniform protocol throughout the state in which daylight saving time would begin on the first Sunday of April and end on the last Sunday of October.
Then, in , the Energy Policy Act of went into effect, expanding the length of daylight saving time to the present timing. However, those who do observe DST take advantage of the natural daylight in the summer evenings. That's because the days start to get longer as Earth moves from the winter season to spring and summer, with the longest day of the year on the summer solstice.
During the summer season in each hemisphere, Earth, which revolves around its axis at an angle, is tilted directly toward the sun. Related: Read more about the science of summer. Regions farthest away from the equator and closer to the poles get the most benefit from the DST clock change, because there is a more dramatic change in sunlight throughout the seasons. Research has also suggested that with more daylight in the evenings, there are fewer traffic accidents, as there are fewer cars on the road when it's dark outside.
More daylight also could mean more outdoor exercise or exercise at all for full-time workers. The nominal reason for daylight saving time has long been to save energy. The time change was first instituted in the U.
During the Arab oil embargo, when Arab members of the Organization of Petroleum Exporting Countries OPEC stopped selling petroleum to the United States, Congress even enacted a trial period of year-round daylight saving time in an attempt to save energy.
But the evidence for energy savings is slim. Brighter evenings may save on electric lighting, said Stanton Hadley, a senior researcher at Oak Ridge National Laboratory who helped prepare a report to Congress on extended daylight saving time in But lights have become increasingly efficient, Hadley said, so lighting is responsible for a smaller chunk of total energy consumption than it was a few decades ago. Heating and cooling probably matter more, and some places may need air-conditioning for the longer, hotter evenings of summer daylight saving time.
Hadley and his colleagues found that the four weeks of extra daylight saving time that went into effect in the United States in did save some energy, about half of a percent of what would have otherwise been used on each of those days.
However, Hadley said, the effect of the entire months-long stretch of daylight saving could very well have the opposite effect. A study in Indiana before and after implementation of daylight saving time in some counties found a small increase in residential energy usage.
Temporary changes in Australia's daylight saving timing for the summer Olympics of also failed to save any energy, a study found. Part of the trouble with estimating the effect of daylight saving time on energy consumption is that there are so few changes to the policy, making before-and-after comparisons tricky, Hadley told Live Science.
In other words, turn all clocks forward permanently. If it did so, I see five ways in which American lives would immediately improve. Simply put, darkness kills—and darkness in the evening is far deadlier than darkness in the morning.
Fatal vehicle-on-pedestrian crashes increase threefold when the sun goes down. DST brings an extra hour of sunlight into the evening to mitigate those risks. Standard time, by moving sunlight into the morning, has precisely the opposite impact. A meta-study by Rutgers researchers demonstrated that lives per year could be saved by moving to year-round DST. The opposite effect would occur if the U. Darkness is also a friend of crime. Moving sunlight into the evening hours has a far greater impact on the prevention of crime than it does in the morning.
This is especially true for crimes by juveniles , which peak in the after-school and early-evening hours. Criminals strongly prefer to do their work in the darkness of evening and night. When the sun is out later in the evening, peak energy loads are reduced. Virtually everyone in our society is awake and using energy in the early evening hours when the sun sets. But a considerable portion of the population is still asleep at sunrise, resulting in significantly less demand for energy then.
Having more sun in the evening requires not just less electricity to provide lighting, but also reduces the amount of oil and gas required to heat homes and businesses when people need that energy the most. Under standard time, the sun rises earlier, reducing morning energy consumption, but only half of Americans are awake to be able to use the sun. Anis Rehman Endocrinologist MD.
Daylight saving time: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. Bryner, J. Daylight saving time When we change our clocks and why. Live Science. American Academy of Sleep Medicine. Barnes, C. Changing to daylight saving time cuts into sleep and increases workplace injuries.
Journal of Applied Psychology, 94 5 , — Monk, T. Spring and autumn daylight saving time changes: studies of adjustment in sleep timings, mood, and efficiency. Ergonomics, 23 2 , Doleac, J. National Conference of State Legislatures. Daylight Saving Time. Boeckmann, C. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Learn more about Circadian Rhythm. Siestas By Sarah Shoen June 30, There's no better time to start the journey to improving your sleep.
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