A Hidden Benefit of Daylight Saving Time?
By Carol Church, Writer, Family Album
Reviewed by Laura Acosta, MS, RD, CSSD, LD/N, Department of Food Science and Human Nutrition, University of Florida
One mom friend of mine calls “Spring Forward” day her least favorite day of the year. I have to admit– I’m not terribly fond of these biannual clock changes either. Although it’s not as bad as it was when my children were babies and toddlers, the shifts forward or back an hour really throw off my kids’ schedules, leading to difficult evenings and cranky mornings.
Why Do We Have DST?
Like a lot of people, I once had the idea that Daylight Saving Time was for “the farmers,” but it’s actually mainly intended as an energy-saving measure, though it also benefits businesses. When daylight lasts later into the evening, we tend to spend more time outside shopping and engaging in tourism. The extra light in the evenings also offers a possible health benefit: more time to be active outdoors.
In a world where children’s outside play time is endangered and where most children don’t get the 60 minutes of daily exercise recommended by experts, this might be no small thing. In 2014, a team of scientists decided to look into the effect of Daylight Saving Time on children’s activity levels, using a huge sample (23,000 children between the age of 5 and 16) from a wide range of countries.
Does DST Affect Children’s Activity?
All the children wore accelerometers, small devices that collect unbiased data on exercise and movement. Looking at thousands of hours’ worth of data across seasons, the researchers compared the amount of time children spent being physically active at different times of year, controlling for temperature and weather. They particularly focused on a smaller group of about 400 children who were tracked both before the clocks went forward for DST and afterwards.
Small Changes Seen
In most of the studies, children were more active in the evening hours (but not at other times of day) once DST went into effect. This could also be seen in individual children, who got more exercise in the evenings once the clocks changed and more light was available. While the difference was small—a couple of minutes per day—it was not insignificant.
Some groups advocate year-round change, a.k.a. “Permanent Daylight Saving Time.” This would eliminate the disruption of the time change while preserving advantages of DST, including allowing more evening light for children to play.
Applicable in the U.S.?
There’s an important point to be made about the findings of this study, however. Although the increased activity levels were found in 11 of the 15 samples examined, four other samples showed no effects—including the two groups from the United States. Why would this be? The researchers think our higher summer temperatures might have something to do with it, but they aren’t sure. More research is needed.
While I’m still not enjoying my dark morning wake-ups, my family does like having more time to run around, kick the soccer ball, and otherwise enjoy the outdoors after dinner. Why not take advantage of the later daylight hours in your family and try to get your own children active outside during these long spring and summer evenings? It’s one effect of the time change families can really embrace.
Let’s Move Outside—Fun ideas for outdoor family exercise
Goodman, A., Page, A. S., & Cooper, A. R. (2014). Daylight saving time as a potential public health intervention: an observational study of evening daylight and objectively-measured physical activity among 23,000 children from 9 countries. International Journal of Behavioral Nutrition and Physical Activity, 11(84), 1-9. http://www.ijbnpa.org/content/11/1/84
Photo Credits: Maria Teijeiro/Photodisc/Thinkstock