Public Health

Both the change of clocks to DST and the continual observation of DST pose lethal threats to human health. Changing clocks causes acute harms that persist for several days or even several weeks.12345 Continually observing DST causes chronic harms that last for months (in the case of seasonal observance) or years without end (in the case of year-round observance). We “never adjust”67891011 to DST—instead we sleep less long and less well than we need.

The abrupt move forward in springtime by one hour is well-known for its shock to body and mind—causing traffic deaths, workplace accidents, lost productivity, and hospitalizations. Incidence of stroke spikes by 9%11 after changing clocks to DST in spring. Incidence of heart attack increases by a range of 24%121314 up to 50%15 the Monday after changing to DST, and this increase continues at a range of 5%10 up to 15%1617 in the week that follows. Even more notably, heart attack rates decrease by a range of 10%10 to 21%121314 after returning clocks to Standard Time in autumn.

Additionally, the observance itself of DST causes subtler but stronger harms. Healthful sleep is necessary for prosperity and longevity, and it’s biologically regulated by melatonin and cortisol. The body’s natural release of these sleeping and waking hormones is tuned to the setting and rising of the sun. DST postpones both sunset and sunrise on our social clock, which disrupts the body’s hormone balance, and leads people both to stay awake late and to feel a need to sleep late.2161718192021222324 However, social schedules demand we wake on time regardless of how we feel, and permanent DST would demand most citizens to start school or work before sunrise for a third of the year (whereas most do not now).1823252627282930

DST’s combination of late daylight and pre-sunrise waking robs us of 19 minutes of sleep every night on average.2463132 Cortisol rhythms advance only two minutes despite clocks being advanced 60 minutes under DST.4 This creates a “social jet lag”, which is far worse for health than ordinary jet lag, and which never is relieved under permanent DST.24212733343536373854 The body attempts to compensate by sleeping late on non–work days, but the benefits of sleep can’t be stored.42133

Researchers warn DST’s chronic lack of sleep “significantly”24621313940 increases risks of heart disease, stroke, diabetes, cancer, high blood pressure, obesity, metabolic disorders, personality disorders, unintentional midday sleep, caffeine abuse, alcohol abuse, depression, and suicidality. It harms cognition, productivity, reaction time, stress management, immunity, and life expectancy, in both children and adults.24681118192122232425262931323334353741424344454647484950515253545556 Delaying sunset and sunrise by one hour increases rates of breast cancer by 5%22 to 12%,26 heart disease by 11%,19 prostate cancer by 12%,2637 colorectal cancer by 13.5%,37 lung cancer by 13.8%,37 heart attack by 19%,22 obesity by 21%2 to 30%,53 liver cancer by 21%26 to 33%,37 stomach cancer by 27%,37 uterine cancer by 30%,2637 leukemia by 36%26 to 39%,Herf and esophageal cancer by 48%.37 Seasonal depression is more prevalent at northerly latitudes (10% of Seattle, 25% of Alaska37), where winter days are unavoidably shorter. This suffering is most effectively relieved by adding light to mornings—not evenings.44957 Desire for DST’s artificially brighter evenings has been compared by scientists to desire for the pleasure of smoking, in that it ignores the volume of data that proves the harm each practice inflicts on individuals and society.58

Proponents of DST claim the practice increases exercise. Circadian scientists consider this claim “de­bunked”.11 Increases in physical activity are better attributed to the natural change of season, not the artificial change of clocks.54 The study to back DST’s exercise claim only considered regions that observe summer DST (ignoring those on permanent Standard Time), its gains averaged just two minutes per day (not the full hour the clock gets advanced), and these small gains were seen only in Europe and Australia (with no gains in America).10 Another study that did compare close regions with different time observations found no increase or decrease in exercise.859 Furthermore, evening exercise can disrupt sleep, and lack of sleep can increase sports injuries by 70%.37

Circadian-health experts “around the world”3132 “unanimously”232736 endorse permanent Standard Time for health, safety, and prosperity as scientific “consensus”.5160 Leading organizations include the American Academy of Sleep Medicine,61 the National Sleep Foundation,62 the Canadian Sleep Society,63 the Canadian Society for Chronobiology,3132 the Society for Research on Biological Rhythms,64 the European Biological Rhythms Society,35 and the European Sleep Research Society.65 See Save Standard Time’s list of policy endorsements for additional organizations and individuals of note who reject permanent DST and support permanent Standard Time.

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Works Cited

1Berk et alSmall Shifts in Diurnal Rhythms Are Associated with an Increase in Suicide: The Effect of Daylight SavingSleep and Biological Rhythms

2Giuntella & MazzonnaSunset Time and the Economic Effects of Social Jetlag Evidence from US Time Zone BordersJournal of Health Economics

3Jennings, HayleyPermanent Daylight Saving Time: Good for Our Health?Grit Daily

4Roenneberg et alDaylight Saving Time and Artificial Time Zones – A Battle Between Biological and Social TimesFrontiers in Physiology

5Smith, AustinSpring Forward at Your Own Risk: Daylight Saving Time and Fatal Vehicle CrashesAmerican Economic Journal

6Curtis, AnnieDaylight Saving Time: Harmed by Hands of the ClockThe Irish Times

7Holliday, IanPermanent Daylight Time Is Worse for the Body, Scientists WarnCTV News

8Kalidindi, AnishaDaylight Saving Time Is Bad for Your Health – We Should Go to Year-Round Standard Time, As the Sun IntendedMassive Science

9Kantermann et alThe Human Circadian Clock’s Seasonal Adjustment Is Disrupted by Daylight Saving TimeCurrent Biology

10Livingston, AmyIs Daylight Savings Time Helpful or Harmful? History & EffectsMoney Crashers

11Watson, NathanielTime to Show Leadership on the Daylight Saving Time DebateJournal of Clinical Sleep Medicine

12Brueck, HilaryDaylight-Saving Time Is Literally Killing UsBusiness Insider

13Michigan Medicine StaffWhy Daylight Saving Time Could Increase Your Heart Attack RiskMichigan Health

14Sandhu et alDaylight Savings Time and Myocardial InfarctionOpen Heart

15Peralta, JessicaWhy Daylight Saving Time Makes You Feel TerribleHealthline

16Livingston, BuzIt’s Time for No More Time ChangesThe Destin Log

17Reddy, SumathiHere’s Why Health Experts Want to Stop Daylight-Saving TimeThe Wall Street Journal

18CBC StaffYear-Round Daylight Time Will Cause ‘Permanent Jet Lag,’ Sleep Experts Warn in Letter to GovernmentCBC

19Crick, KindraOregon Wants to Increase Sleep Deprivation and Winter MiseryThe Oregonian

20Cytowic, RichardToo Many Reasons Why Daylight Saving Time Is Bad for YouPsychology Today

21Gu et alLongitude Position in a Time Zone and Cancer Risk in the United StatesCancer Epidemiology, Biomarkers & Prevention

22Ingraham, ChristopherHow Living on the Wrong Side of a Time Zone Can Be Hazardous to Your HealthThe Washington Post

23Lindsay, BethanyHealth Risk Warnings Ignored as B.C. Moves to Permanent Daylight Time, Researchers SayCBC

24O’Callaghan, LaurenEarly Riser? Waking Up Before Sunrise Increases Risk of a StrokeExpress

25Block & MeijerWho Wants to Go to Work in the Dark? Californians Need Permanent Standard TimeUCLA Newsroom

26Herf & LongcoreWhy Proposition 7 Is Bad for Public HealthMedium.com

27Juda et alAn Open Letter to the BC Government in Support of Permanent Standard TimeSimon Fraser University

28Labbe, StefanDST Switch “Reckless”: Sleep Scientists Slam Switch to Permanent Daylight Savings TimeCastanet

29Meijer & FosterTime to Change—But Only to ‘Wintertime’Daylight Academy

30Sládek et alChronotype Assessment via a Large Scale Socio-Demographic Survey Favours Yearlong Standard Time over Daylight Saving Time in Central EuropeScientific Reports

31Cermakian et alTurn Back the Clock on Daylight Savings: Why Standard Time All Year Round Is the Healthy ChoiceThe Globe and Mail

32CSC StaffOfficial Statement of the Canadian Society for Chronobiology in Support of Year-Round Standard TimeCanadian Society for Chronobiology

33Borisenkov et alSeven-Year Survey of Sleep Timing in Russian Children and AdolescentsBiological Rhythm Research

34Clay, JoannaIs Year-Round Daylight Saving Time a Good Idea? Maybe NotUSC News

35EBRS StaffTo the EU Commission on DSTEuropean Biological Rhythms Society

36Fletcher, TomStandard Time Better for Public Health, B.C. Researchers SayVictoria News

37Herf, MichaelWhy Standard Time Is BetterMedium.com

38McMillan, BradenExperts Call on Government to Adopt Standard Time Instead of Daylight Savings TimeSimon Fraser University Communications

39Lewy et alMorning vs Evening Light Treatment of Patients with Winter DepressionJAMA Psychiatry

40VoPham et alCircadian Misalignment and Hepatocellular Carcinoma Incidence in the United StatesCancer Epidemiology Biomarkers & Prevention

41BBC StaffRussia: Putin Abolishes ‘Daylight Savings’ Time ChangeBBC News

42COFCO StaffImpact of Daylight Savings on ProductivityCOFCO

43Crawford & BoyntonSleep Expert Says B.C. Should Stay on Standard Time Rather Than Switch to Daylight SavingGlobal News

44Daily Hive StaffResearchers Support Abolishing Daylight Savings Time for Better Health and Well-BeingDaily Hive

45Gibson & ShraderTime Use and Productivity: The Wage Returns to SleepWilliams College Department of Economics Working Papers

46Herring, JasonDaylight Saving Time: Alberta Biological Rhythm Expert Raises Alarm over Proposed Permanent SwitchEdmonton Journal

47Jin & ZiebarthSleep, Health, and Human Capital: Evidence from Daylight Saving TimeThe National Bureau of Economic Research

48Karamali, KamilToronto Researchers Push to Eliminate Daylight Saving Time, Switch Permanently to Standard TimeGlobal News

49McCoy, HeathCircadian Rhythm Expert Argues Against Permanent Daylight Saving Time – Move to Permanent Standard Time Better for Public Health, Says UCalgary Psychologist Michael AntleUniversity of Calgary Faculty of Arts

50Merline, JohnTime to Ditch Daylight Saving Time—It’s a Killer That Doesn’t Save EnergyInvestor’s Business Daily

51Ogliore, TaliaWashU Expert: This Year, Let’s Make Standard Time PermanentThe Source

52RIVM StaffStandard Time More Beneficial for Public Health Than Summer TimeRIVM

53Roenneberg et alSocial Jetlag and ObesityCurrent Biology

54SRBR StaffSRBR Talking Points About Daylight Saving TimeSociety for Research on Biological Rhythms

55White, RyanAlberta Psychologist Touts Permanent Move Away from Daylight Saving TimeCTV News

56Zantinge et alStandard Time, Summer Time and Health: A Literature Study into the Health Effects of Different Time SettingsRIVM

57Gillmore, MeaganTalk of Time Change Raises AlarmOHS Canada

58Junge & CunningtonSocial TimeSleep Talk

59Zick, CathleenDoes Daylight Savings Time Encourage Physical Activity?Journal of Physical Activity and Health

60Bui, CrystalNew Bills Aim to Make Daylight Saving Time Permanent in MinnesotaKSTP-TV

61AASM StaffAmerican Academy of Sleep Medicine Calls for Elimination of Daylight Saving TimeAmerican Academy of Sleep Medicine Advocacy

62NSF StaffPermanent Standard Time: A Position Statement from the National Sleep FoundationNational Sleep Foundation Issues

63CSS StaffPosition Statement of the Canadian Sleep Society on the Practice of Daylight Saving Time (DST)Canadian Sleep Society News

64Roenneberg et alWhy Should We Abolish Daylight Saving Time?Journal of Biological Rhythms

65ESRS StaffJoint Statement to the EU Commission on DSTEuropean Sleep Research Society