Daylight Savings Time worse than previously thought

I am sure I have ranted about the negative effects of DST here and back on Circadiana, but the latest study – The Human Circadian Clock’s Seasonal Adjustment Is Disrupted by Daylight Saving Time (pdf) (press releases: ScienceDaily, EurekAlert) by Thomas Kantermann, Myriam Juda, Martha Merrow and Till Roenneberg shows that the effects are much more long-lasting and serious than previously thought. It is not “just one hour” and “you get used to it in a couple of days”. Apparently it takes weeks for the circadian system to adjust, and in some people it never does. In this day and age of around-the-clock life, global communications, telecommuting, etc., the clock-shifting twice a year has outlived its usefulness and should go the way of the dodo. The research also shows why studies of photoperiodism is not some arcane field, but has real-world applications.


32 responses to “Daylight Savings Time worse than previously thought

  1. I don’t personally observe DST. During that silly season, I just do everything an hour early. I switch my clocks from PST to MST. And nobody catches on.

  2. If the change of one hour is destructive, how bad is airplane travel to another time zone?

  3. Jet-lag is nasty and takes forever to reset. But you usually go back home in a few days and go back to normal (good idea is to schedule your life according to your home time instead of local time, which some hotels now accommodate). Moving across the globe may take, apparently, months to adjust. Not healthy!

  4. I love DST! I really just love it! If I were a dictator I would implemment it all year round, with two hours of difference during the summer.
    Personally, I couldn’t care less if it iss still dark when I wake up (and I wake up early) and I enjoy the extra hour of sunshine soooo much! For me, it really boosts quality of life!
    I hope it never goes away!

  5. Daylight SAVING time, not SAVINGS

  6. Without Daylight Saving(s) Time, life wouldn’t be worth living.
    Although yeah, I’d prefer if we kept it through winter as well 😉

  7. Daylight Saving Time is idiotic, in my opinion, although my view of it might be skewed by living in New England—we have more light than we need in the summer anyway, and winter days are too short no matter what. Now, if we could figure out a way to steal an hour of sunlight in the summer and move it to the winter, that would be worth it.

    CBC in Canada has also written about this study. I hadn’t been aware that Canada is divided into large pockets which do and do not observe DST. Of course they don’t mention the USA’s “pocket”, Arizona, which even Expedia’s computers don’t know about.
    In my youth, the arguments against DST involved milk cows. Characteristically it’s taken half a century for it to occur to anyone that the biology of humans might not like this silly custom any better than that of the cows.
    I’d bet that our DST also affects wild animals who live anywhere near human activity. Suddenly the noise of rush traffic, the generosity of people with bird feeders and many other zeitgebers inexplicably switch to an earlier/later time twice a year.

  9. To be honest, I’ve only ever liked the Fall Back bit of DST, where we gain an hour of sleep. I propose that we forget the Spring Ahead nonsense and instead Fall Back twice a year: once in spring, once in autumn. In this respect, we will gain an hour of sleep two times in a 365-day period.
    Furthermore, if we increased the frequency of backfalling and, say, Fell Back every two months (and who would turn down 60 free sleep minutes), over the course of 4 years, we will have gained an entire 24 hours. Then, we could do away with Leap Year.

  10. DST is one of those things that I have looked up and had explained to me repeatedly (because I can’t stop myself, apparently), gets explained differently by each source that I query, gets explained differently on each separate occasion I query the same source, and has never ever ever ever ever ever made any sense to me at all.

  11. Billy (A Liberal Disabled Vet)

    I work for the Federal Government and am part of what is called ‘fire militia.’ This means I am always on call to go anywhere in the country to help with wildland fires, floods, hurricanes (and even 9/11).
    Last summer I went to a fire in northern California. Came to work back East at the usual time — left home at 8:00, work at 8:45. I got a phone call at 10:00 — I’m headed for California. First plane I could get out was at 4:00pm. Arrived in Oregon at 4:00am my time (1:00am local), checked into a hotel, in bed by 5:00am (my time). Ground support picks me up at the hotel at 3:00pm my time and we drive four hours to the fire. I take two hours off and am on night shift (1600 to 0900 with two half hour breaks). I do this for one week. I get shifted to another fire in Oregon. Overnight in Medford, drive up to just east of Portland. Work 0600 to 2000 (with two half hour breaks) for one week. Then it takes me two days to get home to PA, via an overnight in Atlanta.
    This was one of four assignments this last summer — on east coast, two pacific, one mountain. I am STILL messed up on my sleep schedule.
    So I believe that Daylight Saving Time disrupts circadian rythms, but I’m not all that impressed with the one hour difference on a personal level.

  12. But do we still save energy during Daylight Saving months?

  13. this DST nonsense has been an irritant or worse my whole life. When I was a kid our government doubled it up or something as an experiment (can’t remember, due to being constantly sleep-deprived during those school years), and it was supposed to prove all sorts of mainly traffic-safety and energy-saving tweaks. It may well have done way down in Governmentville. Up here in Scotland it was basically irrelevant as it only functioned as intended for a few weeks near the equinoxes. The rest of the working day is either a) dark, except roundabout lunchtime, or b) light, except for a dullish patch round midnight.
    I’d like my sun to return to its traditional position of due south at midday, please, we see little enough of it as it is :�(

  14. These studies give me some evidence I can use to start pressuring the local medical association to do away with this assinine disruption of circadian rhythms. I’ve never personally observed daylight savings time and keep my watch adjusted to standard time all year round. I normally wake up earlier in the summer but have major problems once days start getting shorter. My patients all know my views on daylight savings time and there have been minor problems only when I’ve dated my hospital orders or written time of death in PST. I always include the PST when I write the time. I usually get home so late when I’m working that I don’t get any extra hours of daylight to enjoy on workdays.
    Surprisingly, windoze lets me do this and my office computer is kept on PST year round whereas my receptionist insists on putting her on PDT. The schedule program has no problem in maintaining PST on my machine. Linux, on the other hand, can’t concieve of people refusing to use daylight savings time.

  15. I think we should all live on Sidreal time and set our clocks back by 4 minutes each day.

  16. NEJM
    Volume 335:355-357 August 1, 1996 Number 5
    Traffic Accidents and Daylight Saving Time
    “To the Editor: Coren recently claimed (April 4 issue)1 that returning to daylight saving time in the spring brings an increase in motor vehicle crashes.1 The theory is that the loss of one hour of sleep when clocks are moved forward causes lapses of attention and thus increases the likelihood of crashes. The implication is that in the fall, when there is an additional hour of sleep, drivers will be more alert and less likely to crash.
    “However, evidence from more thorough analyses of crash data shows the reverse. ….”

  17. And
    Losing Sleep at the Market: The Daylight Saving Anomaly
    Mark J. Kamstra, Lisa A. Kramer, Maurice D. Levi
    The American Economic Review, Vol. 90, No. 4 (Sep., 2000), pp. 1005-1011

  18. Thanks for the nice paper.
    And I learned a new word: zeitgeber! Pretty cool.
    I’ve always suspected that it takes a long time to adjust…I get totally confused for weeks. Now I have science backing me up.
    Is there any rationale for keeping DST around still? I assume some powerful lobby group or another has a vested interest in keeping it. Or is it just a case of legal inertia…

  19. And of course, the proof is in the use of 2-week periods for a work schedule of 3 rotating shifts. It takes about 2 weeks to get half-way adujusted to Days, Evenings, or Midnights, and then it’s time to switch again. I worked shifts for about 3 years and never knew when to be hungry. (I settled on one big meal every day.)
    Your nurses and all kinds of 24-hour service are on that kind of schedule, designed in the last century to give everyone a fair share of each shift (early riser, social suicide, and night-owl). Your emergency-room doctors are probably working 100-hour weeks and 24-hour shifts. A lot of other jobs (TV & radio, transport, restaurants, stores) have two shifts to supply “the public” with services during all the hours most people are up. Taxi drivers and such work a lot of 12-hour shifts (and look at their reputation as drivers!) and who knows what truckers do on “long hauls” when no one is looking. At the same time, technology is requiring more attention and finer decisions from everyone. Sounds like an accident waiting to happen to me. Weren’t the Three-Mile-Island crew at the nuclear power plant deep in the night shift?
    Isn’t it about time we recognized circadian rhythms? At least let people settle on one shift. The shifts could be “auctioned” off by seniority, with a payment bonus for non-day shifts. People could then choose one and settle into it. There’s still an adjustment – like coming off the weekend with your family on “normal” time and going back to work at midnight – but it’s a lot easier to handle.

  20. It’s just as mad here in England. But we are not all as polite as you about it …
    Only an idiot thinks we gain daylight by doing this. On top of the time wasted to change clocks, clearly whatever you save in the morning you lose exactly the same amount in the evening. Obviously. Everyone knows that. Except idiots.
    The time taken to change clocks (and timetables) is a non-productive drain on society. Perhaps it was only a minor inconvenience when every home had just one clock in the hall that needed to be regularly synchronised with BBC chimes anyway. Today it is lunacy.
    Changing time is a significant cost for every local business, and it is an enormous cost for every global business. Jet-lag is a real drain too. We force the whole country to endure an hour’s jet-lag twice a year. Ridiculous.
    Some people prefer brighter mornings. Some people prefer brighter afternoons. Don’t try to justify clocking with bullshit about getting closer to nature. The cockerel doesn’t suddenly decide to crow sixty minutes earlier. Cows don’t realise when it’s GMT and trudge down for milking accordingly. Crops ripen according to the sun, not the clock.
    I would prefer to stay on BST. Others would prefer to stay on GMT. But … just leave the damn thing alone.

  21. JohnnieCanuck, FCD

    This idea only works at all for mid latitudes. You basically get sunrise and sunset at 6 o’clock year round near the equator and, what our Scottish dustbubble said, near the poles.
    The problem begins with our being awake nominally for 16 hours when the average day is, again nominally, 12 hours.
    The daylight available to be ‘saved’ is those summer morning hours for which a majority would otherwise be asleep under standard time. This is the rationale for the scheme.
    Its value becomes less and less as people move to large cities and then have to contend with commuter traffic. There is a very large incentive to avoid the rush hour, spreading it out over at least 4 hours. Then there are the 12 hour shifts at hospitals,etc. and the investment brokers and business men in the Pacific time zone who must coordinate with the NY and NASDAQ exchanges.
    It doesn’t look like the health issues will be enough, but global commerce and the Internet may yet eliminate DST.

  22. loki, my newly-installed Ubuntu linux didn’t reset to natural time today, so what you say about it not being able to conceive of people refusing to use daylight savings time is clearly not true. When I looked into it, I found a check box for “Automatically adjust time” linked to a time server, that defaulted to being unchecked.

  23. loki claimed:

    Linux, on the other hand, can’t concieve of people refusing to use daylight savings time.

    Absolute tosh! Set the TZ environment variable accordingly. For constant PST, use the value “PST8”. This can be done on a per-process, per-user, and/or per-system basis. Details (e.g., what file or files to change) will probably vary depending on your distribution and version. You may or may not be able to use one of the supposedly friendly GUI front-ends to do this; it’s not a common setting (AFAIK). (And it’s daylight saving, not daylight savings, time.)
    This has worked on many versions of Unix since at least the mid-1980s, and is part of the 1988 IEEE/ISO POSIX standard (which Linux follows).
    Reinder, are you in the USA? If so, then why would it change from summer (daylight saving) back to standard (normal) time now? Congress, in the 2005 Energy Policy Act, changed the summer time start and end dates; for 2007, it ends on 4th November (next Sunday). To the best of my knowledge, this change is present in all recent Linux versions/distributions, so you shouldn’t have to do anything. (And in any case, time servers (NTP) have little-to-nothing to do with summer/standard time changes.)
    I know there were, and assume there still are, some places in the USA with their own quirks; an up-to-date Linux zoneinfo(?) database and properly-set TZ should handle those cases as well.

  24. There’s no problem with DST, just the change. So the problem isn’t just going TO DST, it’s leaving it (yet the ranters never rant about that end). Solution: Just keep it throughout the year. Recognise we’re not in the 19th century anymore.

  25. Exactly. It is not which time we choose (it is arbitrary anyway), but the fact that we SHIFT is a problem.

  26. Thank you for this article! I suffer from seasonal affective disorder and am particularly sensitive to the time change. Nobody believes me when I say it takes me weeks to adjust. Don’t even ask me about jet-lag. Daylight Saving Time, Standard Time, I don’t care, just pick one or the other and stay with it. This switching back and forth drives me crazy!

  27. Also take a look at this and this.

  28. Jim Thomerson

    I’m for year round DST. As an alternative scheme, the sun comes up at 7:00 AM PERIOD everywhere and always. How’s that for globalization?

  29. Who the hell wants to save daylight in the *mornings*?
    Probably 90% of the population is either at work or asleep at the time of day when daylight is supposedly “saved” by DST – so, if anything, the clocks should go forwards for winter rather than back – thus giving people some daylight in the 5-6pm period, when most people are actually free to enjoy it – but i would prefer it if it stayed the same all year round, and having the sun’s zenith at midday (at least, on the defining meridian of your time zone) seems logical to me.
    Claims that DST needs to be kept for the benefit of farmers make no sense at all to me – it makes no difference whatsoever to crops or animals. I can only assume that, if it benefits anyone to do with agriculture, it must be large agribusinesses or supermarkets (and anything that harms them can only be a good thing, for the world and humanity)…
    Now what *really* doesn’t make any sense to me is the International Date Line…

  30. Well, I second the motion to just stay on it all the time. I’ve never understood all the grousing, aside from the irritation of the shift. Its more efficient to do business during daylight hours so people should just get used to it. What I really want to know is how all you science folk manage to see the light of day frequently enough to have anything resembling circadian rhythms in the first place. Do you all have corner offices with windows or something? I begin to feel as if I’ll turn into a morlock…stupid hole in the ground lab…

  31. ChrisSuitcase

    Myths of Daylight Saving Time:
    -DST lengthens period of daylight(80% of people actually BELIEVE this!)
    -DST saves energy(OK – during 13hour daylight months May throuh July it does)
    Check out:
    DST Facts:
    -I find it much harder to get out of bed when it is still dark at 7AM in March. It jars the body’s circadian rhythm and psyche to raise the shades at 6AM, expecting to observe the vernal equinox, but instead it’s still nearly dark!
    DST was fine when it was observed from early April til late October – the federal government needs to find other ways to occupy its spare time than playing with clocks.

  32. I was just wondering if anyone really knows when the mysterious change to move the clock back one hour. It is not at midnight — I watched my computer clock and it stayed on 12. It did not go back to 11:00. Does it automatically move back in the middle of the night? Do people who work the night shift have to work one more hour — and do they get paid for that extra hour of work?