As Daylight Saving Time approaches, do its benefits outweigh its hazards?

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NEW YORK -- For the 100th time, many nations of the world, including our own of course, will switch to daylight saving time on Sunday. However, the springing forward comes with risks and hazards, as well as benefits.

A look at the history of the time shifting practice, as well as its effects, offers insight into the level of practicality of daylight saving time, or DST.

First, though, confirming terms is helpful. The practice of setting clocks ahead an hour is called daylight savinG time, not "daylight savingS," as many people erroneously call it. It provides an extra hour of daylight at the end of the work and school day.

"It just feels good," said Sergio Esquivel about the benefits of a longer evening. By contrast, though, a Brazilian tourist pointed out the challenge of DST at the other end of the day. "It's hard to wake up in the morning," she said.

That's the least of the problems associated with the changeover to DST every year. As a study published in the New England Journal of Medicine pointed out in 2008, the moving of clocks forward shows an increase in heart attacks in the days after the time shift, at a variety of hospitals monitored over the course of many years.

The study also showed that setting clocks forward negatively affects the duration and quality of sleep. That, in turn, according to other research, can cause an increase in injuries at workplaces and can contribute to more traffic crashes.

However, said David Prerau, PhD, those results are "just for the first day or two or three" after the transition to DST.

Prerau wrote the book, literally, about daylight saving time. As he points out in Seize the Daylight: the Curious and Contentious Story on Daylight Saving Time, increased evening daylight is helpful to most of the 1.5 billion people who spring forward every year.

He said that his research has shown that DST "reduces energy use, decreases traffic accidents and increases public health" over the course of the eight months in which daylight saving time is in effect.