Talk:Daylight saving time

Health effects of Spring circadian rhythm disruption

Health effects of Spring circadian rhythm disruption

The enforced sleep deprivation and circadian rhythm disruption of the Spring time change has a number of adverse health effects. PMID 11152980. The body's circadian rhythm does not readily adjust to the effects of the Spring change; instead, the body continues to slowly adjust to the earlier morning sunlight. PMID 17964164. The circadian rhythm does more readily adjust to the Fall change, which allows an hour of extra sleep PMID 17964164; for instance; an actual reduction of traffic fatalities has been seen following the Fall change. PMID 7832269. Because the Spring change imposes a number of ill health effects, the nation of Kazakhstan discontinued the use of Daylight saving time.

Given the dissaprate effects, it is difficult to understand why there is no delay in the Spring change. The clocks change at about the spring equinox in Europe and the United States, but well over a month after the autumnal equinox.

The opposite would make sense for purposes of health. The body's circadian rhythm readily adjusts to the Fall change, which allows more sleep, but adjusts with great difficulty and slowness to the Spring change, which effective deprives an hour of sleep (measured at just over 60 minutes in one study) and requires rising earlier. After the change, people continued to rise earlier on the weekends in a pattern precisely tuned to the gradually earlier rising of the sun. For health reasons, the Spring change should be delayed for at some weeks after the Spring equinox, to allow the body has the chance to adjust based on sunlight. Possibly a part of the reason that the body adjusts so easily is the Fall is simply that the natural light progression has already occurred in the month following the equinox. See notes in the discussion section above on health effects of circadian rhythm disruption.

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Curr Biol. 2007 Nov 20;17(22):1996-2000. Epub 2007 Oct 25. The human circadian clock's seasonal adjustment is disrupted by daylight saving time.

Kantermann T, Juda M, Merrow M, Roenneberg T.

Ludwig-Maximilian-University, Goethestrasse 31, D-80336 Munich, Germany. Abstract

A quarter of the world's population is subjected to a 1 hr time change twice a year (daylight saving time, DST). This reflects a change in social clocks, not environmental ones (e.g., dawn). The impact of DST is poorly understood. Circadian clocks use daylight to synchronize (entrain) to the organism's environment. Entrainment is so exact that humans adjust to the east-west progression of dawn within a given time zone. In a large survey (n = 55,000), we show that the timing of sleep on free days follows the seasonal progression of dawn under standard time, but not under DST. In a second study, we analyzed the timing of sleep and activity for 8 weeks around each DST transition in 50 subjects who were chronotyped (analyzed for their individual phase of entrainment). Both parameters readily adjust to the release from DST in autumn but the timing of activity does not adjust to the DST imposition in spring, especially in late chronotypes. Our data indicate that the human circadian system does not adjust to DST and that its seasonal adaptation to the changing photoperiods is disrupted by the introduction of summer time. This disruption may extend to other aspects of seasonal biology in humans.

PMID 17964164

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Am J Public Health. 1995 Jan;85(1):92-5. Daylight saving time and motor vehicle crashes: the reduction in pedestrian and vehicle occupant fatalities.

Ferguson SA, Preusser DF, Lund AK, Zador PL, Ulmer RG.

Insurance Institute for Highway Safety, Arlington, Va 22201. Abstract

Fatal crashes were tabulated for 6-hour periods around sunrise and sunset, from 13 weeks before the fall change to standard time until 9 weeks after the spring change to daylight saving time. Fatal-crash occurrence was related to changes in daylight, whether these changes occurred abruptly with the fall and spring time changes or gradually with the changing seasons of the year. During daylight saving time, which shifts an hour of daylight to the busier evening traffic hours, there were fewer fatal crashes. An estimated 901 fewer fatal crashes (727 involving pedestrians, 174 involving vehicle occupants) might have occurred if daylight saving time had been retained year-round from 1987 through 1991.

PMID 7832269 [PubMed - indexed for MEDLINE] PMC 1615292Free PMC Article

Sleep Med. 2001 Jan;2(1):31-36. Fatal accidents following changes in daylight savings time: the American experience.

Varughese J, Allen RP.

Department of Symbolic Systems, School of Humanities and Sciences, Stanford University, CA, Stanford, USA Abstract

Objective: This study examines specific hypotheses that both sleep loss and behavioral changes occurring with the time shifts for Daylight Savings Time (DST) significantly effect the number of fatal traffic accidents in the United States of America.Background: It has been reported that there is a significant increase in the number of automobile accidents in the spring shift to DST due to the loss of 1 h of sleep. But the extra hour gained at night with the shift from DST in the fall has been variably reported to be associated with increases and decreases in the number of automobile accidents which may reflect either behavioral anticipation with an extended late night prior to the change or the benefit of extra sleep after the change.Methods: Data from 21 years of United States' fatal automobile accidents were gathered. The mean number of accidents on the days at the time of the shifts (Saturday, Sunday and Monday) was compared to the average of the corresponding mean number of accidents on the matching day of the weeks preceding and following the shift. This was repeated for each DST shift. The number of accidents for a particular shift was also correlated with the year of the accidents.Results: There was a significant increase in accidents for the Monday immediately following the spring shift to DST (t=1.92, P=0.034). There was also a significant increase in number of accidents on the Sunday of the fall shift from DST (P<0.002). No significant changes were observed for the other days. A significant negative correlation with the year was found between the number of accidents on the Saturdays and Sundays but not Mondays.Conclusions: The sleep deprivation on the Monday following shift to DST in the spring results in a small increase in fatal accidents. The behavioral adaptation anticipating the longer day on Sunday of the shift from DST in the fall leads to an increased number of accidents suggesting an increase in late night (early Sunday morning) driving when traffic related fatalities are high possibly related to alcohol consumption and driving while sleepy. Public health educators should probably consider issuing warnings both about the effects of sleep loss in the spring shift and possible behaviors such as staying out later, particularly when consuming alcohol in the fall shift. Sleep clinicians should be aware that health consequences from forced changes in the circadian patterns resulting from DST come not only from physiological adjustments but also from behavioral responses to forced circadian changes.

PMID 11152980

— Preceding unsigned comment added by Ocdncntx (talk • contribs) 19:53, 13 March 2011‎ (UTC)

See also

General topic

• Daylight saving time around the world
• Time in Canada
• CHU distributes official time in Canada

Official Civil Time Distribution

• WWV & WWVH (NIST Shortwave)
• WWVB (NIST Longwave)

Quasi-governmental time distribution systems

• CDMA cellphone stratum 2 time distribution system
• GNSS global navigation stratum 1 time distribution system

EXUSE ME

this article is presenting an appearance that local time is done by science standards and isn't used for theft, studpidy, or say to dodge court at some trial time, or just plain no one cares.

 # From Rives McDow (1998-10-08):
 # The State of Quintana Roo has reverted back to central STD and DST times
 # (i.e. UTC -0600 and -0500 as of 1998-08-02).

 # From Rives McDow (2000-01-10):
 # Effective April 4, 1999 at 2:00 AM local time, Sonora changed to the time
 # zone 5 hours from the International Date Line, and will not observe daylight
 # savings time so as to stay on the same time zone as the southern part of
 # Arizona year round.

 # From Jesper Norgaard, translating
 # <http://www.reforma.com/nacional/articulo/064327/> (2001-01-17):
 # In Oaxaca, the 55.000 teachers from the Section 22 of the National
 # Syndicate of Education Workers, refuse to apply daylight saving each
 # year, so that the more than 10,000 schools work at normal hour the
 # whole year.

— Preceding unsigned comment added by 72.219.202.186 (talk • contribs) 16:17, 26 March 2014‎ (UTC)

is daylight saving time off?

I was my understanding that this was created to keep the seasons in line with our calender and to adjust the time of day to get more farming time. since now all our seasons are coming late should we make a adjustment? if so how could that affect our norm? say -- oh by the way your birthday is next month. — Preceding unsigned comment added by Jesse1620 (talk • contribs) 02:55, 30 July 2020 (UTC)

This page is for discussing improvements to the article Daylight saving time here at Wikipedia, not for discussion of the topic in general. If an "adjustment" is made, it will be reflected in this article, but we are not going to discuss the need (or lack) for such a change here. General Ization ^Talk 03:02, 30 July 2020 (UTC)

As User:General Ization writes, this talk page is not about whether adjustments should be made, it's about improving the article. If you read the article, you will notice it does not mention keeping the seasons in line with our calendar. That's because daylight saving time has nothing to do with keeping the seasons in line with the calendar. That's covered in calendar-related articles, such as Gregorian calendar. Jc3s5h (talk) 03:39, 30 July 2020 (UTC)

I don't think this article meets the FA criteria

We've got substantial issues with this one here. It's not compliant with WP:LEADCITE. There's significant uncited text. The bit about it and Windows is rather out of date. Additionally, it does seem like a lot of that Windows section is undue weight: it's about half of the computing section, and there's not much information about other operating systems, so I'm not even entirely sure why there's that much information about it. Most of the computing section itself is actually out of date. For instance, the passage "Older or stripped-down systems may support only the TZ values required by POSIX, which specify at most one start and end rule explicitly in the value. For example, TZ='EST5EDT,M3.2.0/02:00,M11.1.0/02:00' specifies time for the eastern United States starting in 2007. Such a TZ value must be changed whenever DST rules change, and the new value applies to all years, mishandling some older timestamps." not only refers to something in 2007 and kinda in the future tense, but it's also sourced to something from 2004. Surely something has changed since 2007. It's completely unclear what the citation to "May 1965, Minnesota Mayhem." is referring to. A lot of the books cited are missing page numbers. And that's only from a quick look. This isn't meeting the FA standards right now. Hog Farm _Bacon 18:04, 9 November 2020 (UTC)

Hog Farm, the amazing editor who originally wrote this article is long gone, and all of his FAs have fallen into disrepair-- in its day, this was quite an undertaking, and I doubt that anyone can restore this to the standard Eubulides brought it over a decade ago. Since the prose size is now more than TWICE what Eubulides wrote,[1] there is likely to be lots of cruft, and FARC is likely. SandyGeorgia (Talk) 18:10, 9 November 2020 (UTC)