They Stole My Morning… Again! (DST Rant)

Daylight Saving Time has to be one of the dumbest social conventions of all time! It’s just a bad idea that should be abolished!! DST doesn’t save energy, negatively impacts the health of millions, and robs me of an extra hour of daylight every morning!

I thought I’d review some recent evidence here. I’ve added emphasis to the most important bits. Decide for yourself!

Changing to daylight saving time cuts into sleep and increases workplace injuries. Barnes CM, Wagner DT.

J Appl Psychol. 2009 Sep;94(5):1305-17. doi: 10.1037/a0015320.

The authors examine the differential influence of time changes associated with Daylight Saving Time on sleep quantity and associated workplace injuries. In Study 1, the authors used a National Institute for Occupational Safety and Health database of mining injuries for the years 1983-2006, and they found that in comparison with other days, on Mondays directly following the switch to Daylight Saving Time-in which 1 hr is lost-workers sustain more workplace injuries and injuries of greater severity. In Study 2, the authors used a Bureau of Labor Statistics database of time use for the years 2003-2006, and they found indirect evidence for the mediating role of sleep in the Daylight Saving Time-injuries relationship, showing that on Mondays directly following the switch to Daylight Saving Time, workers sleep on average 40 min less than on other days. On Mondays directly following the switch to Standard Time-in which 1 hr is gained-there are no significant differences in sleep, injury quantity, or injury severity.

Daylight saving time shifts and incidence of acute myocardial infarction–Swedish Register of Information and Knowledge About Swedish Heart Intensive Care Admissions (RIKS-HIA).
Janszky I, Ahnve S, Ljung R, Mukamal KJ, Gautam S, Wallentin L, Stenestrand U.

Sleep Med. 2012 Mar;13(3):237-42. doi: 10.1016/j.sleep.2011.07.019. Epub 2012 Jan 30.

Our data suggest that even modest sleep deprivation and disturbances in the sleep-wake cycle might increase the risk of AMI across the population. Confirmation of subgroups at higher risk may suggest preventative strategies to mitigate this risk.

Lost sleep and cyberloafing: Evidence from the laboratory and a daylight saving time quasi-experiment.
Wagner DT, Barnes CM, Lim VK, Ferris DL.

J Appl Psychol. 2012 Sep;97(5):1068-76. doi: 10.1037/a0027557. Epub 2012 Feb 27.

The Internet is a powerful tool that has changed the way people work. However, the ubiquity of the Internet has led to a new workplace threat to productivity-cyberloafing. Building on the ego depletion model of self-regulation, we examine how lost and low-quality sleep influence employee cyberloafing behaviors and how individual differences in conscientiousness moderate these effects. We also demonstrate that the shift to Daylight Saving Time (DST) results in a dramatic increase in cyberloafing behavior at the national level. We first tested the DST-cyberloafing relation through a national quasi-experiment, then directly tested the relation between sleep and cyberloafing in a closely controlled laboratory setting. We discuss the implications of our findings for theory, practice, and future research.

The human circadian clock’s seasonal adjustment is disrupted by daylight saving time. Kantermann T, Juda M, Merrow M, Roenneberg T.

Curr Biol. 2007 Nov 20;17(22):1996-2000. Epub 2007 Oct 25.

A quarter of the world’s population is subjected to a 1 hr time change twice a year (daylight saving time, DST). This reflects a change in social clocks, not environmental ones (e.g., dawn). The impact of DST is poorly understood. Circadian clocks use daylight to synchronize (entrain) to the organism’s environment. Entrainment is so exact that humans adjust to the east-west progression of dawn within a given time zone. In a large survey (n = 55,000), we show that the timing of sleep on free days follows the seasonal progression of dawn under standard time, but not under DST. In a second study, we analyzed the timing of sleep and activity for 8 weeks around each DST transition in 50 subjects who were chronotyped (analyzed for their individual phase of entrainment). Both parameters readily adjust to the release from DST in autumn but the timing of activity does not adjust to the DST imposition in spring, especially in late chronotypes. Our data indicate that the human circadian system does not adjust to DST and that its seasonal adaptation to the changing photoperiods is disrupted by the introduction of summer time. This disruption may extend to other aspects of seasonal biology in humans.

Social jetlag and obesity.
Roenneberg T, Allebrandt KV, Merrow M, Vetter C.

Curr Biol. 2012 May 22;22(10):939-43. doi: 10.1016/j.cub.2012.03.038. Epub 2012 May 10.

Obesity has reached crisis proportions in industrialized societies. Many factors converge to yield increased body mass index (BMI). Among these is sleep duration. The circadian clock controls sleep timing through the process of entrainment. Chronotype describes individual differences in sleep timing, and it is determined by genetic background, age, sex, and environment (e.g., light exposure). Social jetlag quantifies the discrepancy that often arises between circadian and social clocks, which results in chronic sleep loss. The circadian clock also regulates energy homeostasis, and its disruption-as with social jetlag-may contribute to weight-related pathologies. Here, we report the results from a large-scale epidemiological study, showing that, beyond sleep duration, social jetlag is associated with increased BMI. Our results demonstrate that living “against the clock” may be a factor contributing to the epidemic of obesity. This is of key importance in pending discussions on the implementation of Daylight Saving Time and on work or school times, which all contribute to the amount of social jetlag accrued by an individual. Our data suggest that improving the correspondence between biological and social clocks will contribute to the management of obesity.

Why Daylight Saving Time Should Be Abolished

I ranted about this last March. Since then Scientific American has made Daylight Savings Time number one on their list of Human Creations the World Would Be Better Off Without.

This week-end SA editor David Biello added his voice to the growing consensus that DST should be abolished.

DST is an ill-conceived anachronism and a bumbling attempt at social engineering. It’s major raison d’être is energy conservation, but there is growing evidence it has just the opposite effect. In their 2008 study of DST in Indiana, Kotchen and Grant concluded…

Our main finding is that—contrary to the policy’s intent—DST results is an overall increase in residential electricity demand.

Times have changed and it is time to stop messing with the clock twice a year!

Get Rid of Daylight Saving Time! (Rant)

I’m sitting in my office at 7am and it is completely dark outside. Why?  We have “sprung forward” on that biannual experiment called Daylight Saving Time. They’ve stolen my morning again, the bastards! DST is an anachronism that should be abandoned. According to Wikipedia…

Modern DST was first proposed in 1895 by the New Zealand entomologist George Vernon Hudson, whose shift-work job gave him leisure time to collect insects, and made him aware of the value of after-hours daylight.

1895? New Zealand?! Bug collecting?!! What on earth were we thinking?

In my view the first few hours of daylight are precious. I try to be “solar” and get up with the sun each day. Problem is, they keep moving the goal posts back and forth. If you live in Florida in the summer this is particularly unfair. Early morning is the only part of the day that is clement and suited for activities outdoors in the fresh air! Old Ben Franklin had the right idea, “If you want to save energy, get up earlier!

There is little evidence that DST saves energy (or anything else for that matter). It does favor certain sports and retail interests, but honestly, are those minor concerns enough to subject an entire society to such disruption twice a year?