Should Daylight Saving Time Be Permanent?

The change itself probably causes the most problems.

War Time Poster
Public Domain War Time poster.

United Cigar Stores

Every year we complain about War Time, as Daylight Saving Time was first known, developed to save energy and give farmers a bit more light. Except the First World War is over and we now have air conditioning and artificial lighting, and there are some questions about whether it saves much energy at all. What has been demonstrated pretty conclusively is that the change in time is disruptive.

Bill to make DST permanent
Marco Rubio et al

Now Senator Marco Rubio and a bipartisan group of politicians have introduced the Sunshine Protection Act (PDF here) to make Daylight Saving Time (DST) permanent nationwide, noting in a press release:

“The call to end the antiquated practice of clock changing is gaining momentum throughout the nation. Studies have shown many benefits of a year-round Daylight Saving Time, which is why the Florida legislature voted to make it permanent in 2018. I’m proud to reintroduce this bipartisan bill to make Daylight Saving Time (DST) permanent, and give our nation’s families more stability throughout the year.” 

He is joined by Democrat Ron Wyden from the opposite corner of the country in Oregon, who says:

“The Sunshine Protection Act takes a common-sense step to provide some much-needed stability for families in Oregon and across the nation, Springing forward and falling back year after year only creates unnecessary confusion while harming Americans’ health and our economy. Making Daylight Saving permanent would give folks an hour back of sunshine during the winter months when we need it most.”

Changing Times Messes Up Our Circadian Rhythms.

Your Circadian Rhythms
Your Circadian Rhythms.  YassineMrabet on Wikipedia 

Our bodies are tuned to the sun, and changing the time confuses our internal clocks. Sumathi Reddy of the Wall Street Journal speaks to Dr. Till Roenneberg of the University of Munich:

“Most of our physiology is governed by a circadian clock. This body clock synchronizes to the sun time”...When you travel to a different time zone your circadian clock adjusts to a new darkness-sunlight cycle in a few days. In daylight-saving time, the dark-light cycle doesn’t change but the time does. So there is a discrepancy between your biological clock and social clock, which researchers refer to as “social jet lag,” Dr. Roenneberg said. Permanent standard time is closer to the sun’s natural time so social jet lag is reduced, he added.

The implication of this is that we should go with Standard Time because it is closest to sun time.

“Daylight-saving time means that we virtually live in another time zone without changing the day-light cycle,” Dr. Roenneberg said. “The problem is the misalignment. The circadian clock is trying to optimize our physiology. Now suddenly we have to do things which are not at the biologically appropriate time.”

How Did We Get Here?

last spike
Hammering the Last Spike in Canada/ Public Domain

Everyone used to live on Local Time where they lived, but this was a problem if you were in the railroad line. Sandford Fleming (the guy in the tall hat standing behind Lord Strathcona who is driving the last spike) figured out time zones so that everyone would be able to figure out where the trains were supposed to be. But we are not trains; noon should be noon wherever you are, not at 11:34 in Boston today and 12:42 in Detroit. What works for the convenience of Sandford Fleming and the railroads (and later, Walter Cronkite and the TV networks) doesn't work for our bodies. Really, both Standard and DST are off unless you live smack in the middle of a time zone, but Standard time is a closer approximation.

More: Find out when it is solar noon where you live.

Does the Time Change Cause Heart Attacks and Car Crashes?

We have noted that these time changes are really bad for your health, including an increase in the number of heart attacks and car crashes. But according to Paul Taylor, writing in the Globe and Mail, the research may be sketchy.

The research into the increase in the number of crashes was done by Stanley Coren, Ph.D. of the University of British Columbia, studying the rate of crashes on the first Monday after the switch. When he wrote his letter to the New England Journal of Medicine in 1996 it was still common to say accident instead of crash so I will not change that:

study on crashes
Stanley Koren via New England Journal of Medicine
"These data show that small changes in the amount of sleep that people get can have major consequences in everyday activities. The loss of merely one hour of sleep can increase the risk of traffic accidents. It is likely that the effects are due to sleep loss rather than a nonspecific disruption in circadian rhythm, since gaining an additional hour of sleep at the fall time shift seems to decrease the risk of accidents."

Others disagree with Dr. Coren and question the results; a doctor at Sunnybrook Hospital in Toronto looked at 16 different studies and concluded: “Looking at the sum total of evidence – and not just one cherry-picked study – my impression is that, if there is an association, it is modest.”

Then there is the question of heart attacks, which we have discussed before, and which is based on a Swedish study which found that "heart-attack cases increased by about 5 percent in the week after the clocks were adjusted – both in the spring and the autumn." Taylor questions that one too:

"In particular, many studies that fail to show an effect don’t end up in the medical journals. 'We tend to publish only the stuff that is interesting and will catch people’s attention. The papers that don’t find an association are less likely to be published,' [cardiologist Dr.] Ko says. That can lead people to conclude certain things have a greater impact than they actually do. Ko says he thinks the association between the daylight time switch and heart attacks is real. But, he adds, that risk is likely small and probably affects only those with existing heart disease."

Fine. But anyone with kids and dogs knows that this time change is totally disruptive, and really doesn't serve any purpose. Pick one and just keep it year-round. Or even better, just go Local Time and forget about running on War Time, Railway time or Cronkite time, and go with Your Time.

Does the Time Change Save Energy?

Meta analysis
Tomas Havranek et al

Thanks to the prevalence of air conditioning, any energy savings are negligible. Indeed, a recent meta-analysis "162 estimates from 44 studies and find that the mean reported estimate indicates slight electricity savings: 0.34% during the days when DST applies."

Is the Time Change Good For Business?

spending in LA
JP Morgan Chase/ Shedding Light on Daylight Savings Time

One of the justifications for maintaining DST is that is good for business; it has been thought that the extra light in the evening meant more people in stores. This was recently studied by JP Morgan Chase in Shedding Light on Daylight Savings Time, where they compared sales receipts in Los Angeles, where there is DST, to Phoenix, which is in one of the few states that does not switch to DST.

And indeed, Los Angeles showed that the extra hour of daylight increased sales in stores by about one percent. However this was swamped the loss of sales, a drop of 3.5 percent, when the clocks were turned back in November. In total, throughout the year, the effect appears to be more negative than positive.

"The increase in spending at the beginning of DST is determined by comparing daily card spending per capita in the 30 days before DST starts, to daily card spending per capita in the 30 days after DST starts. The decrease at the end captures a similar window to compare spending in the 30 days before and after the end of DST. Most of the impact stems from responses at the end of DST, when spending on goods drops more than spending on services, and spending during the work week drops more than weekend spending. The magnitude of the spending reductions outweighs increased spending at the beginning of DST."

The shock of the dark evenings in November keeps people out of stores more than the extra hour in the spring brings them in. And now that online shopping is an available option, there is even less reason to subject people to this change, which is not very good for our health:

DST Can Kill You

In 2016 we reported on a study described in STAT which suggests that switching to Daylight Saving Time can kill you.

"A 2013 study of nearly 1,000 patients at two Michigan hospitals compared admissions for heart attacks during the seven days after the move to daylight saving to the same days two weeks prior. In the study, which looked at data between 2006 and 2012, researchers found 17 percent more heart attacks after 'springing ahead,' with a 71 percent spike on the first day, Sunday. In fact, that one day accounted for almost all of the overall increase."

It's not just heart attacks either.

"Analyzing a decade worth of strokes in Finland, scientists found a brief spike in the incidence of ischemic stroke (the most common kind, caused by a clot blocking blood flow in the brain) after the clocks are turned ahead compared to the week before. The rate was 8 percent higher during the first two days after setting the clocks ahead, Dr. Jori Ruuskanen of Finland’s University of Turku and colleagues reported. But in people over 65, the incidence of stroke on those Sundays and Mondays was 20 percent higher."

John Oliver is Not a Fan of DST

... and is quite funny about it:

However there is one positive effect: apparently, there is a sharp reduction in street crime rates. According to Business Insider, a recently published paper shows that the extra light in the afternoon discourages potential offenders.

"Results show that daily cases of robbery, a violent and socially costly street crime, decrease by approximately 7% in the weeks after DST begins, with a 19% drop in the probability of any robbery occurring. A 27% decrease in the robbery rate during the sunset hours drives much of this result."
save daylight
Public Domain

Ending DST Could Solve Climate Change!

A few years back, the transition to Daylight Saving Time happened on April 1st, so of course, with tongue in cheek, we calculated impact that an extra hour of sunlight every day had on the world and announced that ending DST could solve global warming.

"Treehugger Labs ran the numbers and has determined that If DST runs half the year for an hour a day, that is fully 1/48th of our total exposure to the sun that could be eliminated with the cancelling of Daylight Saving Time, almost 2% of solar heat gain annually. That's huge!"
time change letter
Screen Capture

A surprising number of readers were convinced. In 2007 the Arkansas Democrat published a letter complaining about the earlier start of DST:

You would think that members of Congress would have considered the warming effect that an extra hour of sunlight would have on our climate. Perhaps this is another plot by a liberal congress to make us believe that global warming is a real threat.

Pick One and Stick With It

We have tried to make the case for getting rid of both Standard and Daylight Saving Time and going with local time, As Dr. Michael Antle of the University of Calgary explained:

"Humans live by three clocks. These include the light clock, or, solar clock, and the body clock, with the circadian system in our brains. Third is the social clock, governed by the demands of work, school, and other social responsibilities and activities. While our circadian clock is meant to follow the solar day, society dictates that we follow the social clock. 'The problem is that our social clock and our circadian clock are often in conflict, "

Given the complexities of local time, logic would dictate that we pick Standard because it is closest to local. But it's complicated; store owners love DST for the extra light for shopping; Movie theater owners and TV stations loved Standard Time and fought about it, but since the pandemic this has become far less relevant. Parents of young children prefer Standard to get their kids in bed earlier, as do construction workers and some athletes who like the extra early morning light.

There are pluses and minuses to each, but the one thing that we do know is that the original point of the exercise, to save coal and make life easier for farmers, are no longer relevant. The bigger issue is that it is the shift, the change in the time is what hurts the most. So let's just pick one and stick with it.

View Article Sources
  1. "Rubio, Colleagues Reintroduce Bill to Make Daylight Saving time Permanent." U.S. Senator for Florida, Marco Rubio, 2021.

  2. Reddy, Sumathi. "Here’s Why Health Experts Want to Stop Daylight-Saving Time." The Wall Street Journal, 2020.

  3. Coren, Stanley. "Daylight Savings Time and Traffic Accidents." New England Journal of Medicine, vol. 334, no. 14, 1996, pp. 924-925, doi:10.1056/nejm199604043341416

  4. Havranek, Tomas, et al. "Does Daylight Saving Save Electricity? A Meta-Analysis."  The Energy Journal, International Association for Energy Economics, vol. o, no. 2.

  5. "Shedding Light on Daylight Saving Time." JPMorgan Chase & Co, 2016.

  6. Begley, Sharon. "Not just lost sleep: Can switching to daylight saving time kill you?" STAT, 2016.