There is one more reason to keep Daylight Saving Time. A new study reveals that Daylight Saving Time benefits children because the extra daylight increases their physical activity, which, in turn, makes them healthier.

Researchers from the London School of Hygiene & Tropical Medicine and the University of Bristol studied more than 20,000 children between the ages of 5 and 16 in nine countries, including parts of Europe and the U.S. Researchers fitted each child with an accelerometer that measured their body movements before and after sunset.

The results showed that children had activity levels 15 to 20 percent higher on days when the sun set after 9 p.m than they had on days when the sun set before 5 p.m. This was even more pronounced with European and Australian children, even after researchers added in factors such as weather conditions and temperature.

The second part of the study followed 439 children in countries that participate in changing the clocks twice every year. Their activity levels were higher during Daylight Saving Time, which offers more daylight hours in the afternoon, than without it.

"This study provides the strongest evidence to date that, in Europe and Australia, evening daylight plays a role in increasing physical activity in the late afternoon and early evening - the 'critical hours' for children's outdoor play," says Dr. Anna Goodman, lead author of the study. "Introducing additional daylight savings measures would affect each and every child in the country, every day of the year, giving it a far greater reach than most other potential policy initiatives to improve public health."

Recently, the concept of changing the clocks is a controversial one. The idea itself is a throwback to World War I, when governments, including that of the U.S., decided that seasonal changes like this saved fuel. The government repealed the law after the war, but it returned in World War II and has remain unchanged to this day.

This study is just one of many recommending we keep Daylight Saving Time year-round. In 2008, the U.S. Department of Energy found that extending Daylight Saving Time by just four weeks saved about .5 percent electricity per day in the U.S. (enough power for 100,000 households).

Another study shows that changing the clocks back and forth also affects human health, and that switching the clocks in spring causes a 25 percent increase in heart attacks shortly after.

With a clock change happening on Sunday, these studies suggest we should re-think if we really need Daylight Saving Time, or if it, like many other things in modern civilization, is nothing more than an outdated tradition.