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Let’s Not Spring Forward.

The views expressed are those of the author and are not necessarily those of Scientific American.

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Cross-posted from Zocalo Public Square.

Even cows don’t like Daylight Saving Time. Come Sunday morning, when the milking machines get attached to their udders a whole hour too early, the otherwise placid bovines on dairy farms around the United States will snort in surprise and dismay. They may give less milk than usual. They could take days or weeks to get used to the new milking schedules.

We are no different. While most of us won’t be hooking ourselves up to udder pumps, our bodies next week will experience a disturbance very much like the cows’ – one that can affect our mental and physical health. The reason lies in the clash between sensitive, eons-old biology deep within our cells, and human-imposed time-keeping traditions that are barely a century old. Twice every year, when we “spring forward” and “fall back,” our bodies must do battle between “sun time” and “social time.”

Before the mid-19th century, time was more flexible. Each town and village maintained the local church clock more-or-less in sync with the natural light-dark cycles of the sun. The spread of railroads changed all that. The need to keep trains moving in and out of stations at predictable times forced the adoption of a standardized time. That, in turn, led to the formation of time zones.

Daylight Saving Time (DST)—the resetting of all clocks twice a year—was first proposed by New Zealand entomologist George Vernon Hudson in 1895, for quite selfish purposes. He was studying daily cycles in insects and wanted to be able to do more of it during daylight hours. But his idea of maximizing daylight soon spread. The first country to adopt DST was Germany in 1912. Most other countries soon followed, including the United States, which instituted DST in 1918.

The leading argument in favor of DST has always been that it saves energy. Back in the early 20th century, most energy was used for lighting. So, the argument went, placing work and school schedules within daylight hours would save electricity. People wouldn’t need to use light bulbs to navigate around their homes, offices, factories, and fields in the dark, and they would have more time in the evening to indulge in commerce and entertainment.

Today, the situation is very different. The proportion of total energy that is used for lighting is miniscule compared to other, time-independent uses like factories, computers, nuclear plants, airport radars, and other facilities that run 24/7. Energy companies themselves have measured the effect, and have concluded that DST does not save energy.

With this knowledge, some nations have started re-thinking the concept. Russia, for example, abandoned the clock change in 2011, keeping one time all year round. Iceland and Belarus did the same. On the other hand, in 2007, U.S. Congress, clinging to the notion that DST saves energy, moved the onset of DST three weeks earlier than before. That change, I think, makes a difficult transition even more stressful.

Although Congress can impose these changes, it’s a bit unclear who exactly has the right to determine whether DST is implemented. Until very recently, a large number of individual counties in the state of Indiana refused to go through the clock-changing ritual. Arizona doesn’t change its clocks at all—the only state in the union (apart from Hawaii) to defy DST altogether. This lack of clarity about who is in charge may be one of the reasons why a more sustained effort to abolish DST has been unsuccessful nationwide.

Whether or not DST saves energy is the least of the reasons why it’s a bad idea. Much more important are the health effects of sudden, hour-long shifts on our bodies and minds. Chronobiologists who study circadian rhythms know that for several days after the spring-forward clock resetting – and especially that first Monday – traffic accidents increase, workplace injuries go up and, perhaps most telling, incidences of heart attacks rise sharply. Cases of depression also go up. As the faint light of dawn starts preparing our bodies for waking up (mainly through the rise of cortisol secretion), our various organs, including the heart, also start preparing for increased function. If the alarm clock suddenly rings an hour earlier than usual, a weak heart can suffer an infarct.

The reason for negative health effects of DST is that, in essence, the entire world is jet-lagged for a few days. Unlike some animals, like honeybees and reindeer, humans have a very robust circadian clock system that resists abrupt shifts.

Every cell in our bodies contains a biological clock which coordinates the events in those cells—for example, when gene transcription turns on and off, or when specific proteins are made. When we are exposed to a light-dark cycle that is different from what we experienced the previous days, some types of cells synchronize to the new environmental cycle faster than the others. Cells in our eyes, for example, may adjust in about a day, while cells in our brains take a couple of days. Cells in the digestive system and liver may take weeks. So, for weeks after the DST clock change, our bodies are like a clock shop in which each timepiece cuckoos at a different time of day—a cacophony of confusing signals.

Our bodies are constantly being pulled apart by conflicting demands of the natural ‘sun time‘ and culturally imposed ‘social time‘. People living in urban areas may be better shielded from the sun time than their rural counterparts, because of artificial lighting and the skyglow it produces, but nobody is completely isolated from its influence. Twelve noon according to the clock is not twelve noon according to the planet. Citizens of Barcelona and Bucarest are almost two hours apart in their perception of sun time, yet live in the same social time—the same time zone that encompasses most of Europe.

Even those of us who are lucky enough to work from home and can generally set our own work schedules are not completely immune to the effects of DST. I still have to drive my daughter to school at the time prescribed by the local clock, not by local sunlight. My colleagues have expectations about when I will pick up the phone for a teleconference or respond to their emails. I am supposed to show up for my dental appointment at 7am, not “two hours after dawn”.

But if I ever buy a cow—and that is not as crazy as it sounds since I live next door to a dairy farm—I have a plan. Of course I’ll ignore the bi-annual clock changes, which I hear many smart dairy farmers already do. But I’ll go a step further and ignore social time altogether, milking her at the sun time her nervous system can understand, probably the crack of dawn. Whatever I do, I will never make her suffer through the sudden shift of DST. And none of us human animals should suffer it, either.

Image: Dirk Hanson

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Comments 25 Comments

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  1. 1. Laphroaig forever 8:43 am 03/7/2013

    In Canada, the province of Saskatchewan does not observe Daylight Saving Time. Also, here on the East Shore of Kootenay Lake, just north of Idaho, we do not change our clocks either. Starting DST on March 10th seems ridiculous especially for those of us who live north of the 49th parallel. Canada should consider opting out of DST.

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  2. 2. jthistle 10:54 am 03/7/2013

    Everyone in North America has a view on this. I live on the most eastern edge and as a matter of personal preference agree that the twice annual change is an unnecessary burden. But. Let’s change again in March, and then not “fall back”. The extra light at the end of a day has value to me (and I suspect many others) whereas all my mornings are in darkness anyway.

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  3. 3. Bora Zivkovic 10:56 am 03/7/2013

    Despite the title (which is tongue-in-cheek), I really only have a problem with the bi-annual switch and am agnostic on which time to permanently keep. Perhaps staying on ‘summer time’ all the time is the best solution.

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  4. 4. BillR 12:10 pm 03/7/2013

    Puerto Rico, a “commonwealth” of the United States, does not change clocks either. They are always on Atlantic Time.

    I hate the time change. Especially when it either robs me of an hour sleep or causes me to miss a program on TV the night before because I head to bed an hour early to compensate. As though I will actually be able to fall asleep an hour earlier….

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  5. 5. ATLDave 12:38 pm 03/7/2013

    Ending DST is all well and good for those with flexible work schedules. For those of us who have a hard time leaving the office or workplace before 6:00pm, the only portion of the year when we can do daylight outdoor activities after work is during DST. For instance, a quick 9-hole half-round of golf after work is impossible on standard time, but becomes very possible for several months thanks to DST.

    The change-over is painful, but it’s well worth the investment.

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  6. 6. Bora Zivkovic 12:40 pm 03/7/2013

    That is a good point, which is why I am leaning more toward keeping summer-time permanent than standard “winter” time. But switches are bad – they don’t save anything, and they kill people to a great cost to the society.

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  7. 7. drparent 12:51 pm 03/7/2013

    I propose Schrodinger’s Clock. At any given position of the Sun relative to the surface of the Earth, you are both early and late to any given event. When you arrive, observing the location of the event, you will determine whether you have missed it or should wait a bit longer. Who needs numbers! Just show up.

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  8. 8. OgreMk5 2:54 pm 03/7/2013

    Speaking only as the parent of a young child. DST is very hard. My boy wakes up with the sun. Even though his room is completely shielded, he still wakes up best just after sunrise.

    But what’s harder is to tell him he has to go to sleep when the sun is still up. It’s a bloody battle every night. And it’s much harder to get him to school in the mornings when it’s dark.

    Personally, I say let’s call it a draw between regular and DST, move the clocks up half an hour and be done with it.

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  9. 9. turell 3:47 pm 03/7/2013

    We have a horse ranch. Let’s agree to Bora’s suggestion, DSS forever.In WWII there was double DSS and that was fine also. It is the agriculture states that like standard time, and I really don’t see why.

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  10. 10. Bigems 9:02 pm 03/7/2013

    instead of changing the time. just change the schedule. instead of 9-5, work 8-4 and everyone gets out in the day.

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  11. 11. Upper Pen-Michigan 12:16 pm 03/8/2013

    I concur with OgreMk5–our children suffered mightily in school when DST was instituted each spring. It is not normal for a child to get up in the dark–they were zombies in the morning and never really recovered. And I agree that the toughest part was to try to get them to bed when it was still light out at 9 or 10 pm. This is an impossible situation for all the school children. Our local school districts start at 7:30 am, even for elementary age, so the kids go to school in the dark almost all year. Just this week the school start time and sun began to make sense, and then guess what, we have DST, 3 weeks earlier than we used to have it, and also extended in the fall.

    Both my children are now in college, so I can get up with the sun regardless of the official time, but I often think of all the kids being tortured all year with this! And it is NOT the one week when the time changes that is the issue-it is expecting young kids to function while getting up in the dark and being put to bed (but not falling asleep) when it is still light out for much of the school year. I think in other states school schedules may have been adjusted for just this reason. But here school administrators and teachers want the light after school for their recreation time, so I don’t see any school scheduling changes on the horizon. Maybe we should give all students and teachers an hour off in the middle of the day, to get their outside recreation time, and let the poor kids get up with the sun, not in the dark.

    One more thing that adds to the insanity in our area–the Western Upper Peninsula of Michigan–we are on Eastern Time, so our time and sun are already out of wack. Add DST, and we have light until 11 pm in the summer–yikes. The 4 southern counties of the Upper Peninsula successfully petitioned the US Commerce Department to go back to Central Time, as they border Wisconsin and WI is sensibly on Central Time. All of Michigan was originally in the Central time zone, but downstate Michigan wanted to change to Eastern, for reasons I can’t figure out. A statewide vote changed both peninsulas to Eastern, even though the Upper Peninsula residents voted to stay on Central Time (like Wisconsin and Illinois, which are to the south and east of us).

    My final thought: the recent extension of DST in 2007 was driven by a downstate Michigan congressman who likes to play golf in the light (as ATL Dave mentions, you can get a round of golf in after work when DST is instituted).

    Thousands upon thousands of school kids are suffering every day, sleeping through class, not doing well in school, having miserable mornings and tension filled evenings as their parents try to get them to sleep before the sun goes down, all so some can golf after work? Does this makes sense?

    Our electricity use was the same after the DST, because we had to turn all the lights in the house on every morning to try to wake up the kids.

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  12. 12. rshoff 1:57 pm 03/8/2013

    I’d say let’s spring forward, but never again fall back! DST helps in my battle with depression. It’s not a simple personal preference, it medicinal.

    For those far north, your day swings too much between the season to be affected greatly by DST, and for those closer to the equator it swings to little to be of consequence. Those of us in between somewhere feel the effects the most. And for me and many like me, DST is an important part of life.

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  13. 13. rshoff 2:00 pm 03/8/2013

    @upper pen – Why in the world does the school day start so early just to let out early? Why not start at a more reasonable hour and end a little later?! Instead of your commented 7:30 why not 8:00 or 8:30? Was the early school start coordinated for the convenience of some parents?

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  14. 14. shimself 5:35 pm 03/8/2013

    I think you might have given a namecheck to
    “Social Jetlag”

    I never understand the name Daylight Savings being applied to SUMMERtime. In wintertime, sure, daylight is in short supply and there is some logic in setting the clock so as to maximise its availability, so daylight is saved or at least not wasted. But in summertime there’s plenty to go round, whatever you do with the clocks.

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  15. 15. Upper Pen-Michigan 9:22 pm 03/8/2013

    @rshoff- school “starts” at 8:00 am, but rural bus routes or even in our case driving by car 13 miles over rural roads, means out the door between 7:00 and 7:30 to start your day. Getting up, taking a shower, and eating breakfast consume at least 30 minutes (and this is for a fast mover), so most kids are up by 6:30 or 6:45, when it is still dark. Many children wait for a bus in the cold and dark. Not the way I’d ever choose to start my day!

    I’m guessing you live somewhere in the eastern part of your time zone, whatever it is. Our weird situation of being way west of the originally drawn eastern time zone, makes us a bit unique, I guess. It certainly makes DST a non-starter for us. We are on the same time as Washington DC, yet we are 1,000 miles away (mostly west); 18.5 hours of driving time.

    You must have a job where you do not have the opportunity to get outside until later in the day. I wish not only the schools but employers would think about a mid day break, or as someone suggested above, work 8 am – 4 pm.

    I do think that DST has resulted from our national lawmakers living (and playing golf…) on the east coast in the very eastern part of the ET zone. I just want school age kids to get up with the sun and have a happy productive day, and then naturally fall asleep when it gets dark. And yes summer days are quite long this far north, so by May and June the effect is not as bad. “Spring forward” is an absolute horror though (even when it used to take place 3 weeks later; now it is absurd to have it take place on the 2nd Sunday of March).

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  16. 16. adamsmith36 2:28 pm 03/10/2013

    The trouble with bloggers is they always need to find something to write about.
    Paragraph 6 you talk about energy demand. You list nuclear power plants. I thought they were a net electrical energy producer.
    Humans cannot accommodate shift in light/dark cycles? Due to the earth’s tip and seasonal changes, the light/dark period changes naturally.
    Should we ban all jet travel across time zones due to heart attack risk?
    What about shift workers on rotating shifts?
    Bloggers are able to work anytime of day or night they choose.

    I choose to enjoy my long summer evenings outdoors.

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  17. 17. Bora Zivkovic 2:53 pm 03/10/2013

    This just in – DST actually results in MORE energy waste:

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  18. 18. Accordingtosmith 4:14 pm 03/10/2013

    I won’t argue against all the nasty side-effects of DST the author has listed since I cannot speak to the veracity of the claims, but it seems a little extreme that we can be so set in our ways that a one-hour time shift has such detrimental effects. I wonder if this says something important about modern society and the things we perceive as “stress”.

    I certainly understand why folks who live predominantly indoors, and those who live within say, 20 degrees of the Tropics might prefer to abolish DST. Unfortunately for me, I do not live within that zone, so here there is much more variance in daylight hours over the seasons. As someone who spends a great deal of time outdoors I look forward to those longer evenings of daylight. Of course DST would make no difference to me at all were it not for the fact that I also have to deal with the rest of working civilization that needs to keep itself coordinated via time-keeping, and therein lies the rub; individually, none of us need DST, but as a society, there are definite advantages. Coming back to the hazards the author listed, it suggests to me that we have some very unhealthy and maladapted individuals in our society; but of course we already knew that.

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  19. 19. Bora Zivkovic 8:04 pm 03/10/2013

    Don’t blame Ben Franklin for daylight savings, it was kind of a joke:


    The Entomologist who invented Daylight Saving Time:

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  20. 20. Bora Zivkovic 8:06 pm 03/10/2013

    And a new study that shows that DST switch actually leads to more energy waste:

    “Having the entire state switch to daylight-saving time each year, rather than stay on standard time, costs Indiana households an additional $8.6 million in electricity bills. They conclude that the reduced cost of lighting in afternoons during daylight-saving time is more than offset by the higher air-conditioning costs on hot afternoons and increased heating costs on cool mornings….”

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  21. 21. David Gage 8:00 pm 03/11/2013

    The first step before discontinuing this silly man created adjustment to where in time we are would be to have the eastern US states have their own time zone like Canada’s eastern provinces. This would keep those in NYC and Boston (the 2 biggest cities where the change should be made) fromm having to get up in the middle of the morning in the months of May through July. However, knowing the American system of government this is almost an impossible thing to fix as it will take the decision making skills of the few in office and not the majority of those who have to work through these silly and unnecessary changes twice a year.

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  22. 22. bongobimbo 11:58 pm 03/12/2013

    Amen! I was born in 1936, raised in the Midwest and South, where rural counties refused to change the clocks since (as explained above) cows don’t like it and neither do people. After the rise of the suburbs with their silly lawns, we called it the “Lawn Mowing Law”. I’m now 77. I’ve hated DST all my life. Since it’s only useful for lawn mowing after work, it’s time to dump it.

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  23. 23. ARFA52 6:31 pm 03/13/2013

    As someone who works 12 hour shifts on a 3 on,2 off rota, my body clock is totally screwed.At the end of a 6 week rotation ,I and my team mates, don’t even know which day of the week it is!In the UK we barely get 6 hours of daylight in winter anyway, and our employers insist that there is no health risk! In my humble opinion, we should shift work and school hours to suit the available daylight,and remind them that ,when the clocks go back, we work an extra hour for nothing!

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  24. 24. AKlarsfeld 5:39 am 04/12/2013

    I generally enjoy this blog, but here I find it a bit misleading.
    No health consequence due to time switching has been reported to last for more than 2-3 days. Many studies actually report no significant effects. It is true that a Scandinavian study found a small but significant excess of heart attacks when “springing forward”. However, it also found a DECREASE (although admittedly smaller) when “falling back”. Both variations, however, were much smaller than the difference in baseline heart attacks in the fall versus the spring !
    One should also remember that holidays in Greece or Egypt also expose to 1h switches back and forth within just a few days (or weeks for the lucky ones ;-) .
    This is actually the case for Barcelonians going to Bucharest (or the opposite), since the two cities are not in the same time zone, contrary to the blog’s assertion.

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  25. 25. jeepien 11:26 am 11/3/2013

    It is not at all “unclear” who has the authority to determine the rules regarding DST. For many years now, it has been Congress. Federal law also determines the dates on which the changes will be made. But the law does allow individual states (not counties) to opt out of DST entirely. Arizona and Hawaii have done so.

    The recent situation in Indiana was also a state decision, but a split one. Any state that straddles more than one time zone may make separate opt-in/out decisions for each zone. Indiana originally chose to make the DST switch in its Central-zone portion, but to stay on standard time in the Eastern zone all year long.

    Ultimately, though, Indiana reconsidered, and decided that the entire state would drink the spring-forward-fall-back Kool Aid, and that’s how things stand today.

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