October 24, 2007
Humans Do Not Adjust To Daylight Savings Time

If I was king one of the things I'd do is abolish Daylight Savings Time (though I'd ban car lock and car alarm horn beeping first). In my view Daylight Savings Time is a manifestation of the modern tendency of humans to try to deny their biological nature. No, we can't just en masse shift our sleep cycles without some cost to be paid. I like it when science produces evidence that confirms my intuitions. Well, here is some scientific evidence for the idea that Daylight Savings Time is a bad idea.

In a large survey, which examined the sleep patterns of 55,000 people in Central Europe, Roenneberg’s group now shows 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, they analyzed the timing of sleep and activity for eight weeks around each of the two DST transitions in 50 people, taking into account each individual’s natural clock preferences, or “chronotypes,” ranging from morning larks to night owls. They found that the timing of both sleep and peak activity levels readily adjust to the release from DST in autumn, but that the timing of activity does not adjust to the start of DST in spring, especially in those who like to stay up late and sleep in.

“While we generally think that the time changes enforced by the DST transitions are ‘only an hour,’ they have far more drastic effects if viewed in the context of the circadian clock’s seasonal changes,” Roenneberg said. “This seemingly small hour translates to a repeat of 10 weeks in the annual progression of the relationship between our sleep-wake cycle and dawn—four weeks in spring and six weeks in autumn. In effect, it’s as if the entire population of Germany, for example, is transported to Morocco in spring and back again in autumn.”

Indeed, “after taking the seasonal adjustment into account, our results show that the human circadian clock does not adjust to the DST transition,” Roenneberg said. “This is especially obvious in the late chronotypes in spring when one looks at their daily activity patterns. Essentially, their biological timing stays on standard, winter time, while they have to adjust their social schedules to the advanced clock time throughout the summer.”

A lot of high school kids are probably the ones most in need of escape from what some adults foolishly think is a good idea. Forcing kids to adhere to schedules that make them really sleepy in class is a big waste.

Share |      Randall Parker, 2007 October 24 10:11 PM  Brain Sleep

Evil Sue said at March 8, 2009 11:21 AM:

How do we abolish daylight savings altogether. It is an outdated idea that serves no good purpose whatsoever. I do not understand why no one changes it. I do not understand why people don't band together to change it permanently. No matter how you slice it there will always be 24 hours in a day.

Jitka Grubner said at March 12, 2009 8:03 AM:

A great site with a lot of information about this subject is www.standardtime.com. There is also a new site starting up www.enddst.org.
I hope we can ban DST soon it drives me nuts twice a year and spoils springtime for me every year.

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