What is the science behind #LockTheClock?
Health – Overall
- Permanent Daylight Saving Time reduces deaths.
Nature and Journal of Population Economics (Summary)
- Risks from a wide range of health problems (including kidney failure, wrist injuries and many others) climb in the days after the “spring forward” time change.
Public Library of Science Journal of Computational Biology
- The “spring forward” change means more overall deaths from heart attacks, traffic accidents, suicides and other causes.
Intl. Journal of Environmental Research and Public Health and Intl. Journal of Legal Medicine and a review of studies by the Wake Forest Law Review.
- The human circadian system does not adjust into DST.
- Medical errors go up after the spring change.
Journal of General Internal Medicine
Health – Specific Conditions
- Heart attacks go up because of the clock change.
New England Journal of Medicine, Sleep Medicine Journal, European Journal of Public Health, European Heart Journal
- Strokes and incidents of Atrial Fibrillation go up because of the clock change.
Circulation Journal, and Sleep Medicine Journal
- Clock-changing increases IVF miscarriages.
- Deaths from drug overdoses and suicide would decline with no time change and permanent DST
City University of New York
- Deaths from suicide and drug overdose increase in the days after the spring time change
Journal of Health Economics
- The “Fall Back” change brings an increase in depression.
Journal of Epidemiology
- Permanent Standard Time is better for treating Seasonal Affective Disorder.
Archives of General Psychiatry
- Year-round Daylight Time means people walk and ride bikes more.
Journal of Environmental Psychology
- The ability to search for objects among distractions (and play video games) goes down in the week after the DST clock switch.
The Journal of Vision
- Ending clock changing helps sleep, and standard time is better than permanent DST for sleep.
Journal of Biological Rhythms, Journal of Health Economics.
(Although, other studies, like this one from Chronobiology International, say that better sleep from permanent DST is “relatively small.”)
- The clock change compromises sleep duration and efficiency, and regulation of cortisol.
- People living in permanent DST would burn more calories and spend more time riding bikes.
University of Washington, and Proceedings of the National Academy of Sciences
Children and Schools
- There is NO increased risk to children in rural areas and we would save lives of school children with Permanent DST.
American Journal of Public Health, Thread from Rep. Marcus Riccelli of Wash, and, Washington State study.
- Again, there is simply no evidence that school children are put at risk by year-round DST.
Congressional Research Service, citing multiple studies.
- Permanent DST helps in the fight against childhood obesity.
Journal of Behavioral Nutrition and Physical Activity and Journal of Physical Activity and Health and the International Journal of Behavioral Nutrition and Physical Activity
- The clock changing costs teens sleep.
American Academy of Sleep Medicine
- Staying in DST will improve traffic safety in the winter months, and there is NO increased risk to students waiting for school buses.
Journal of Safety Research and Royal Automobile Club Foundation
- Traffic accidents spike in the week after “Spring Forward.”
American Economic Association, New England Journal of Medicine, Sleep Medicine
- The “Spring Forward” change kills about 28 people every year just in traffic accidents, just in the U.S.
Current Biology, summary here
- Traffic accidents will be reduced overall with Permanent Daylight Saving Time
National Network of Researchers in Economics
- Permanent DST reduces hit and run accidents, and increases the chance that the driver will flee
European Journal of Law and Economics
- Permanent DST will save lives of pedestrians, drivers and vehicle occupants.
Accident Analysis & Prevention and Sleep Medicine and Muenchen University and the Royal Society for the Prevention of Accidents and Charles University.
- Fatal accidents are much higher in the far western parts of U.S. Time Zones, and would be reduced if time zone boundaries were moved east.
Time & Society, summary here.
- Traffic crashes drop dramatically in DST and rise in Standard Time
Journal of Safety Research
- Permanent DST would save 33 lives, 2,054 injuries and $1.19 Billion in accident costs by reducing collisions with deer.
Energy and Environment
- Evidence mixed, but it does appear that Permanent DST saves energy.
U.S. Department of Energy, and the Italian Society of Environmental Medicine, and Lancet.
- Permanent DST will help decrease air pollution.
Journal of the Air & Waste Management Assn.
- Staying in DST all year can save wildlife.
Journal of Environmental Management and The Royal Society Biology Letters
- DST changes make computers use extra energy.
The Windows Club
Crime and Human Behavior
- Crime goes down in Daylight Saving Time.
Review of Economics and Statistics, and the Institute of Labor Economics
- Crime goes up in Standard Time, down in DST.
Inter-American Development Bank, and the Global Labor Organization
- DST reduces homicides.
Universities of Brazil and Italy
- Moral Awareness and willingness to help others goes down after the Spring time change.
Journal of Sleep Research, and Public Library of Science – Biology
- People are less civil online after the Spring time change.
Stevens Institute of Technology
- Workplace injuries go up.
Journal of Applied Psychology
- Workplace productivity goes down because of the clock changes.
Journal of Applied Psychology, story here
- Getting rid of clock changing will make the stock market perform better, and reduce over-reactions by investors.
Journal of Psychological Reports and Journal of Banking and Finance
- Switching out of DST hurts retail sales.
JP Morgan Chase Institute
- Permanent DST is better for society overall than Permanent ST
University of Washington Law School
- Voters further east in a time zone prefer Permanent DST, and Permanent ST for those further west.
Journal of Biological Rhythms
- The spring clock change makes marathon runners 12 minutes slower.
- Clock-changing harms relationships.
Wall St. Journal, citing several studies, subscription required
- Clock-changing brings harsher sentences from judges.
- It’s a non-partisan issue, and farmers have traditionally been opposed to DST.
Social Science Quarterly
- Scientists don’t subject lab rats to clock-changing because it is too disruptive.
NPR interview with neuroscientist
- People do worse at video games after a clock change, showing that cognitive function overall goes down.
George Washington University and U.S. Army Research Lab
- Declarations about the clock relative to the sun and sleep are probably too simplistic given the complexities of the science.
LMU – Munich
- While year-round Standard Time may be better for sleep, scientists who believe that should not push that point of view dogmatically because they will alienate people from science.
Clocks & Sleep
(In fact, this is a great paper to read if you are thinking about using any of this research to push the point of view that permanent Standard or Daylight time is better. It’s very hard to say. The only thing conclusive is that changing the clocks, especially in the spring, is deadly.)
Also, here is the excellent study done in the state of Massachusetts:
The Report of the Special Commission on the Commonwealth’s Time Zone, or download here.
And here is a handy report prepared for the Missouri legislature in 2022:
Summary and Full PDF.
If you would like to use all this research, you are of course welcome to, but I would appreciate a link to this site. Thanks.