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‘Fall back’ time switch may be harder on larks than night owls

You may have gained an hour over the weekend as we ditched daylight saving time for standard time.

But do you feel more rested?

In theory, you should. After all, you had an extra 60 minutes this morning to get your act together before heading out to work (if you still have a job in this recession, that is). And, if you had wanted to, you could have spent that hour asleep under your comforter, reliving in your dreams the Minnesota Vikings’ great victory yesterday. 

But a small Finnish study published late last year came to an interesting conclusion about the transition out of (in the fall) and into (in the spring) daylight saving time. 

It found that the fall transition was more difficult for morning-type people. Those are the people whose internal biological clocks, including the ones that determine alertness, rev up early in the morning. You know — the people (mea culpa) who are annoyingly chipper at the breakfast table, even without a cup of coffee. 

This finding surprised the study’s authors, as standard time contributes a bonus hour of light to the mornings — the period of the day so beloved by morning people. 

Almost all the participants in the Finnish study — morning and evening people alike — slept less efficiently in the days after the fall time change than after the spring change. (Sleep efficiency = actual sleep time divided by time in bed.) Their sleep was, on average, 54 percent more fragmented and disrupted in the fall compared to 37 percent in the spring. 

But it was the morning people who seemed to feel the effects of that fragmented sleep. 

Of course, evening-type people (those who mumble their way through breakfast but who are wide-eyed at midnight) have their own time-adjustment struggles. But their nemesis is the hour they lose in the spring, when we switch back to daylight saving time. In fact, their biological clocks may never truly adapt to the change. 

A final note: Last year, a Swedish study found a small association between heart attacks and our twice-yearly time shifts. Heart attacks increased for the first three weekdays after the transition to daylight saving time in the spring, but only for one day after the change to standard time in the fall. 

Um, that one day is today. 

So take it easy. And for all you morning people who are feeling a bit sluggish today: Try an extra cup of coffee this morning.

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