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J Schor on Daylight Savings Time



Saving Time:
Jacob Schor ND FABNO
November 6, 2011

Rena and I are in Toronto this weekend. We were both invited to the Canadian College of Naturopathic medicine to speak to students at an annual event known as ‘The Gathering.’ Though it sounds like the title of a book by that fellow Stephen King, it’s actually an interesting attempt, organized by the students rather than the schools, to gain exposure to various schools of medical thought in particularly the more traditional naturopathic views of treatment philosophy.

It seems that this trip has coincided with the time changing; well I suppose that should more accurately be stated as our changing of the clocks. Thus our waking up with sunrise at 6:30 am is now 5:30 am. Though the math isn’t difficult I still refuse to think what time it is or was in Denver.

Let me use these hard won few minutes to update my files on Daylight Savings Time.
Several recent publications have me thinking about Daylight Savings Time (DST) in particular. The rationale used to justify DST has slipped away and published data suggests that DST may be detrimental to our health. Now of course the astute among you will remind me that this newsletter might be better timed in the Springtime when we do jump ahead and set our clocks earlier but I find that I’m too tired then to spare the time to think about these things.

Benjamin Franklin is credited with being the first to suggest the use of DST. This stems from a letter Franklin wrote while living in Paris in 1784 in which he half-jokingly calculated how much money might be saved if people were to wake earlier in the morning. At the time the fashion was to stay up late and sleep through the morning, at least in the wealthy crowd Franklin was hung out with. By Franklin’s calculations, the 100,000 inhabitants of Paris could save 64,050,000 pounds of candle wax over a 6-month period.[1] Franklin as typical, was ahead of his time.

Before we consider DST we need to back up and remember that the concepts of standard time and time zones are recent inventions. We have lived with these arbitrary arrangement all our lives and as a result take them for granted.

As the earth rotates on its axis, the sun appears to move across the sky in an arc. Here in Toronto, because we are at higher latitude than Denver, the arc is noticeably lower in the southern ski at this time of year. Depressingly so. Noon is when the sun reaches its daily zenith, the highest point in the sky; in past times this was when clocks were set to 12:00. Local time varied along longitudinal lines that were perpendicular to the equator. The further west you went, the earlier in the day it was. The sun arrives later in Vail than in Denver. The sun sets in Chicago long before it does in Denver. (it rises earlier in Toronto) Every town had its own town clock and operated on its own time. This worked fine when people traveled by foot. When they said local time, they meant local time.

Development of the railroads created the need for standard time, that is all clocks in all towns on a rail line, set to the same time. Without a common time how could trains run on schedule? Britain was the first to use a standard time. Dr. William Wollaston (1766-1828) is credited with coming up with the idea that was then popularized by Abraham Osler (1808-1903). The Great Western Railway was the first to adopt London Time and by 1847 most British railroads had done the same. By 1855, most clocks in Britain were set to Greenwich Mean Time (GMT) though the legal system held out and didn’t adopt GMT until 1880 causing all sorts of curious peculiarities that seem perfectly suited for the British to have tolerated. The image that the train conductor’s vest pocketed time-piece that is still ingrained in our minds, a remnant of that period of change when ‘railroad time’ first trumped local time.

William Lambert first proposed time standardization and time zones in the U.S. back in 1809. Yet his idea wasn’t adopted until 1883. Detroit held out longest, keeping their local time, 28 minutes later than Central Standard Time, until 1900.

Daylight Savings Time:
During the First World War, Germany and Austria initiated DST on April 30, 1916, moving their clock hands one hour ahead to conserve energy. The rest of Europe, Canada and Australia immediately copied the Germans. The U.S. held out until 1918. DST was unpopular in our country and was repealed in 1919.

Roosevelt re-instituted year-round Daylight Saving Time from February 1942 to September 1945. It was a free for all from 1945 to 1966 with states and localities making their own decisions whether to observe DST. Confusing? You bet, especially for TV, radio, trains, and airlines.

In 1974, Nixon signed into law the Emergency Daylight Saving Time Energy Conservation Act and implemented the Daylight Saving Time Energy Act setting clocks ahead. Congress amended the Act, and Standard Time returned in October 1974. Daylight Saving Time resumed on February 23, 1975 and ended on October 26, 1975. Looking back it all appears rather arbitrary, almost chaotic.


These days in most of the United States Daylight Saving Time begins at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. That would be this morning.

There are problems coming to light with this entire DST business. First off it’s dangerous and second it doesn’t ‘save’ anything.

In 2004 the Journal of the American College of Cardiology published an article on the ‘Effect of sleep loss on C-reactive protein, an inflammatory marker of cardiovascular risk.’ In simple terms missing sleep triggers an inflammatory reaction, a reaction that we now know increases risk of having a heart attack or stroke.

When we shift into and out of DST we disrupt our circadian clocks. Actually it’s more complicated than that. Although work and school schedules follow the clock, biological rhythms stick with the sun and don’t adjust like we pretend they do.[2] Messing with internal clocks is trouble. Even waking on time for work on Monday mornings is a problem.

Back in 2005 the European Journal of Epidemiology reported that men were more likely to have heart attacks on Mondays than any other day of the week. “The odds ratio (OR) of sudden cardiac death on Monday compared to other days of the week was 1.20 ….. The excess mortality due to the Monday peak amounted to 4.9 per 1000 deaths. The Monday peak was more pronounced in non-hospitalized ….. than in hospitalized patients …..” [3]

So when you feel like everything is an up hill slog through mud on a Monday morning, well, your heart agrees with you.


Real concern about DST started, just before a ‘time shift’ when, on October 30, 2008, the New England Journal of Medicine published an article, “Shifts to and from Daylight Saving Time and Incidence of Myocardial Infarction.” Imre Janszky of the Karolinska Institute carefully evaluated Swedish medical records and found, “The incidence of acute myocardial infarction was significantly increased for the first 3 weekdays after the transition to daylight saving time in the Spring…. In contrast, after the transition out of daylight saving time in the autumn, only the first weekday was affected …..”

Jansky explains this phenomenon; “The most plausible explanation for our findings is the adverse effect of sleep deprivation on cardiovascular health. According to experimental studies, this adverse effect includes the predominance of sympathetic activity and an increase in pro-inflammatory cytokine levels. Our data suggest that vulnerable people might benefit from avoiding sudden changes in their biologic rhythms.”

“… people in Western societies are chronically sleep deprived, since the average sleep duration decreased from 9.0 to 7.5 hours during the 20th century. Therefore, it is important to examine whether we can achieve beneficial effects with prolonged sleep.”

Noting the prior reports of higher infarction risk on Mondays were explained as simply associated, “with the mental stress of starting a new workweek and the increase in activity,” Jansky provides another explanation, “… that there is another, sleep-related component in the excess incidence of acute myocardial infarction on Monday. Sleep-diary studies suggest that bedtimes and wake-up times are usually later on weekend days than on weekdays; the earlier wake-up times on the first workday of the week and the consequent minor sleep deprivation can be hypothesized to have an adverse cardiovascular effect in some people. This effect would be less pronounced with the transition out of daylight saving time, since it allows for additional sleep.”

Sleep deprivation and attempts to suddenly shift circadian rhythm create inflammatory reactions in the body makes sense. That these changes can be measured in mortality still is surprising. [4]


Though this association with DST and heart attack risk is new, according to a 2001 paper, safety experts knew already to expect increased car accidents during shifts both into DST in the spring and out of it in the fall.[5]

Not all research agrees with this. A 2010 summary of traffic accident data from Minnesota tells us the opposite. “Daylight saving time can lead to fewer crashes on roads by providing better visibility for drivers.”[6] Well then is the opposite true? Does switching to Standard Time wreck havoc?

While it is becoming clear that DST isn’t good for us physiologically, the rationale that DST saves energy and money has also fallen behind. In an op-ed piece in the November 20, 2008 New York Times Matthew Kotchen and Laura Grant from the university of California, Santa Barbara, talked about their research that disproves this idea.[7] In Ben Franklin’s time it was relevant to calculate candle wax spared from using “sunshine rather than candles” but his calculations have also fallen behind and lost relevance.

Kotchen and Grant conducted “… a study in Indiana, where daylight time was instituted statewide only in 2006. Before that year, daylight time was in effect in just a handful of counties. This change of policy offered a unique, natural experiment to measure the overall effect on residential electricity consumption.”

They found, “that daylight time caused a 1 percent overall increase in residential electricity use….. Daylight time costs Indiana households an average of $3.29 a year in higher electricity bills, or about $9 million for the whole state.”

Why such an increase?
“…[while] daylight time reduces demand for household lighting, it increases demand for heating in the early spring and late fall (in the mornings) and, even more important, for cooling on summer evenings. Benjamin Franklin was right about candles, in other words, but he did not consider air-conditioners.”

They point out that, “In regions of the United States where demand for air-conditioning is greater than in Indiana, this spike in cooling costs is likely to be even greater.”[8]

Their article was based on a paper they have written for the National Bureau for Economic Research.


So if DST increases heart attack incidence, perhaps increases car accidents, and costs us more in energy consumed, why do we do this? There doesn’t seem to be a good reason, it’s just something we tried and turns out doesn’t work. Franklin’s candle wax calculation were written half in jest, not so much as a practical suggestion, but more as a critique of life in Paris where the well off rarely got out of bed before noon. It may prove to unmake this tradition or perhaps the energy saving that could result from repealing the DST laws may make it a no-brainer.

In the meantime, come April, it would make sense to address the increased health risks associated to changing to DST, at least with our high risk patients. The easiest fix would be to make the change gradually, for example, changing the alarm at daily ten-minute increments for a week rather than the full hour on one day. I plan to tell our front desk to start my patient appointments later for a few days.


Ben Franklin’s letter:
http://www.webexhibits.org/daylightsaving/franklin3.html

2004. Journal of the American College of Cardiology published and article on the ‘Effect of sleep loss on C-reactive protein, an inflammatory marker of cardiovascular risk.’ http://content.onlinejacc.org/cgi/content/abstract/43/4/678?ijkey=3dd2b39a00b5b0cb5f33f0c47e9416cd91a6d225&keytype2=tf_ipsecsha

Jansky’s article in NEJM: http://content.nejm.org/cgi/content/full/359/18/1966

References:

1. Franklin, Ben. Letter to the Editor of the Journal of Paris, 1784

2. Kantermann T, Juda M, Merrow M, Roenneberg T. The human circadian clock's seasonal adjustment is disrupted by daylight saving time. Curr Biol. 2007 Nov 20;17(22):1996-2000. Epub 2007 Oct 25.

3. Witte DR, Grobbee DE, Bots ML, Hoes AW. Excess cardiac mortality on Monday: the importance of gender, age and hospitalisation. Eur J Epidemiol. 2005;20(5):395-9.

4. Imre Janszky. Shifts to and from Daylight Saving Time and Incidence of Myocardial Infarction. NEJM. Vol. 359:1966-1968, Oct 30, 2008, Num 18.

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

6. Huang A, Levinson D. The effects of daylight saving time on vehicle crashes in Minnesota. J Safety Res. 2010 Dec;41(6):513-20. Epub 2010 Nov 25.

7. New York Times November 20, 2008 Op-Ed Contributor
What’s the Point of Daylight Time?
By MATTHEW J. KOTCHEN and LAURA E. GRANT

8. New York Times
November 20, 2008
Op-Ed Contributor
What’s the Point of Daylight Time?
By MATTHEW J. KOTCHEN and LAURA E. GRANT

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