Less evening light could reduce childen’s activity levels, according to a meta-analysis by the London School of Hygiene and Tropical Medicine and the University of Bristol in the UK that makes a case against setting the clocks back in autumn.

Lead study author Anna Goodman and her team worked with 15 studies in nine countries that examined a total of 23,188 children aged 5-16 years who wore Actigraph accelerometers to measure their body movement. Data was collected between 1997 and 2009.

The researchers then took into account the time of sunset and the local weather characteristics in the place where the data had been collected.

The research team was most interested in the data of 439 of the children because it had been submitted either immediately before or immediately after a spring-forward-fall-back time change.

After adjusting for weather, they found that longer evening daylight was associated with increased physical activity, and most strongly in boys.

According to their data, they say foregoing that hour of sleep in the fall would only result in two minutes of increased physical activity per day. This represents, however, a five percent increase in physical activity for children estimated to be spending 33 minutes a day on physical activity, and should be perceived as a step in the right direction, say the researchers.

The study was published in the International Journal of Behavioral Nutrition and Physical Activity.