Daylight Savings Time, Is It Good for Us?

Photo: Ileana Johnson 2015

As my body struggles each spring to cope with the Daylight Savings Time (DST), I wonder if it is beneficial to humans and what effect does it have if any on loss of productivity due to sleep deprivation, on health, and potential accidents. Who decided first that it was a good idea to turn clocks forward one hour in spring and wind them back in the fall? Did it save significant amounts of energy and thus money?

At 2 a.m. on the second Sunday in March until 2 a.m. on the first Sunday in November, all states except Arizona, Hawaii, and territories, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the Virgin Islands observe DST. Seventy other nations around the world also follow DST.

Benjamin Franklin, then Minister to France, proposed in 1784 to reset the clocks when the sun came up and people were still sleeping, saving one million francs per year in candles.

A British builder, William Willett, proposed in 1907 to move hours of work and recreation more closely to daylight hours, cutting back on artificial light. The bill he proposed in Parliament did not pass.

To conserve fuel, Germany started DST on May 1, 1916. During the war, most of Europe also adopted DST.

In the U.S., DST was not formally adopted until March 19, 1918, establishing both standard time zones and summer DST to start on March 31, 1918. Because the idea was unpopular, Congress abolished DST after the war, overriding President Woodrow Wilson’s veto. Some states observed DST until WW II. At that time, President Franklin Roosevelt established “War Time” on February 9, 1942 which ended on the last Sunday in September 1945. The following year, many states adopted summer DST.

According to the Congressional Research Service, the Uniform Time Act of 1966 (P.L. 89-387) established federal regulation across the country because the transportation industry needed consistency in time observance. Clocks were to be set forward one hour on the last Sunday in April at 2 a.m. and set back on the last Sunday in October. An entire state could exempt itself from the law, including states that were located in split time zones, as long as the entire state would follow the same time. Arizona exempted itself in 1968 and in 1972 the act was amended to allow states split in different time zones to be exempted or be entirely included in DST. The Department of Transportation became the law’s enforcer.

The OPEC oil embargo of 1973 prompted Congress to have a trial period of year-round DST in order to conserve energy and fuel. Benefits advertised were more recreation, reduced light and heating demand, reduced crime, and reduced auto accidents. Many worried about children going to school in the dark. After the trial period, in 1975 the whole country returned to DST.

The DOT found that “modest overall benefits might be realized by a shift from the historic six-month DST (May through October) in areas of energy conservation, overall traffic safety and reduced violent crime” when the DST was proposed to be changed to March-November.

Beth Cook wrote that the DOT reported, “These benefits were minimal and difficult to distinguish from seasonal variations and fluctuations in energy prices.” (March 9, 2016, CRS, R44411, p. 2)

Cook also wrote, “Congress then asked the National Bureau of Standards (NBS) to evaluate the DOT report. In an April 1976 report to Congress, Review and Technical Evaluation of the DOT Daylight Saving Time Study, NBS found no significant energy savings or differences in traffic fatalities. It did find statistically significant evidence of increased fatalities among school-age children in the mornings during the four-month period January-April 1974 as compared with the same period (non-DST) of 1973. NBS stated that it was impossible to determine, what if any of this increase was due to DST. When this same data was compared between 1973 and 1974 for the individual months of March and April, no significant difference was found for fatalities among school-age children in the mornings.” http://www.fas.org/sgp/crs/misc/R44411.pdf

The Uniform Time Act of 1966 was modified in 1986 to change DST to first Sunday in April through last Sunday in October and in 2005 when Congress changed DST to second Sunday in March and ending it the first Sunday in November. Congress also asked the Department of Energy (DOE) to report on the impact of extended DST on energy consumption. DOE sent this report to Congress in 2008. (Fred Sissine, CRS RL32860, Energy Efficiency and Renewable Energy Legislation in the 109^th Congress)

Cook enumerated some studies on energy savings, health, and safety:

-          Department of Energy (DOE) studies in 2006 and 2008 revealed that ”Total potential electricity savings benefits of DST are relatively small, 0.01 percent to 0.03 percent of total annual U.S. energy consumption.” http://www1.eere.energy.gov/ba/pba/pdfs/epact_sec_110_edst_report_to_congress_2008.pdf

-          “There is general consensus that DST does contribute to an evening reduction in peak demand for electricity, though this may be offset by an increase in the morning.” (M.B. Aries and G.R. Newsham (2008), “Effect of Daylight Saving Time on Lighting Energy Use: A Literature Review,” Energy Policy, 36(6), 1858–1866.)

 

-          “Our main finding is that, contrary to the policy’s intent, DST increases electricity demand.” A trade off was identified between “reducing demand for lighting and increasing demand for heating and cooling.” http://environment.yale.edu/kotchen/pubs/revDSTpaper.pdf

-          A. Huang and D. Levinson, studying the effects of DST on vehicle crashes in Minnesota, found in 2010 that “the short term effect of DST on crashes on the morning of the first DST is not statistically significant.” http://nexus.umn.edu/papers/daylightsavingstime.pdf

 

-          T. Lahti et al found in their 2010 study, “Our results demonstrated that transitions into and out of daylight saving time did not increase the number of traffic road accidents.” (T. Lahti et al., 2010, “Daylight Saving Time Transitions and Road Traffic Accidents,” Journal of Environmental and Public Health, 657167)

 

-          Y. Harrison found in his 2013 that “The start of daylight saving time in the spring is thought to lead to the relatively inconsequential loss of 1 hour of sleep on the night of the transition, but data suggest that increased sleep fragmentation and sleep latency present a cumulative effect of sleep loss, at least across the following week, perhaps longer. The autumn transition is often popularized as a gain of 1 hour of sleep but there is little evidence of extra sleep on that night. The cumulative effect of five consecutive days of earlier rise times following the autumn change again suggests a net loss of sleep across the week. Indirect evidence of an increase in traffic accident rates, and change in health and regulatory behaviors which may be related to sleep disruption suggest that adjustment to daylight saving time is neither immediate nor without consequence.”  http://europepmc.org/abstract/MED/23477947

 

-          MR Jiddou et al in their 2013 study, “Incidence of Myocardial Infarction with Shifts to and From Daylight Savings Time,” The American Journal of Cardiology, 111(5), 631-635,  stated, “Limited evidence suggests that Daylight Saving Time (DST) shifts have a substantial influence on the risk of acute myocardial infarction (AMI). Previous literature, however, lack proper identification necessary to vouch for causal interpretation. We exploit Daylight Saving Time shift using non-parametric regression discontinuity techniques to provide indisputable evidence that this abrupt disturbance does affect incidence of AMI.”

If savings in electricity are relatively small, cumulative sleep deprivation has been demonstrated which could result in productivity loss and traffic accidents, and potential health effects, why are we embracing DST? Wouldn’t following nature’s biological clock be more beneficial to our wellbeing?