Children are particularly prone to unhealthy habits and behaviors, thanks in no small part to commercials heavily advertising fast- and unhealthy food. In fact, childhood obesity, according to the Centers for Disease Control and Prevention, has more than doubled in children (quadrupled in adolescents) over the last 30 years. The silver lining is that children are inspired to get up and outside for exercise when the sun sets later. So British researchers investigated how much of a difference it would make if daylight savings (DST) applied all year long.

DST — the designated times people adjust their clocks to “fall back” (coming up this Sunday, Nov. 2) or “spring ahead” — used to be mandatory when first passed as a law in 1918. It wasn’t very popular, so in 1919, the law was overturned and became optional. Clocks don’t actually determine when the sun rises and sets, but it does give the illusion it rises or sets earlier or later. And we’ve all enjoyed sweet summertime: increased time equals increased sunlight equals increased fun and (if you choose) exercise.

Knowing this, British Parliament proposed shifting clocks forward by an additional hour year round, which they presumed would add an average of 200 extra waking daylight hours per year. Current research looks back on this bill, citing that it lacked sufficient evidence regarding physical activity. This prompted researchers to cull children’s physical activity data already logged in The International Children’s Accelerometry Database courtesy of 20 studies previously conducted in just as many countries. As the database title suggests, physical activity was recorded through waist-worn accelerometers.

With over 20,000 sets of data, researchers determined a later hour of sunset was associated with increased daily activity. An analysis of that analysis revealed it was in “the late afternoon and evening that the duration of evening daylight was most strongly associated with hourly physical activity levels.” Yet, when adjusting for weather conditions, children living in mainland Europe, England, and Australia were averaging more physical activity during this time compared to children living in North and South America. The difference may have to do with higher temperatures in certain areas inhibiting summertime activity.

“This study provides the strongest evidence to data that, in European and Australian settings, evening daylights plays a causal role in increasing physical activity in the later afternoon and early evening—a period which has been described as the ‘critical hours’ for children’s physical activity,” researchers concluded. “In these settings, it seems possible that additional daylight saving measures could shift mean population child physical activity levels by any amount, although small in absolutel terms, would not be trivial relative to what can feasibly be achieved through other approaches.”

The recommended daily amount for children’s exercise is 60 minutes. This seems like a lot, but the American College of Sports Medicine suggests playful activities, like walking, balking, dancing, jumping rope, basketball, Frisbee, and skating can get kids moving while this whole DST gets sorted out.

Source: Goodman A, Page A, Cooper A. 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. 2014.