School children are not getting enough physical activity during the school day, largely because few states require it, researchers reported.

In a cross-sectional analysis of nearly 1,800 schools in 47 states, only 6% of states required a daily recess period, according to Sandy Slater, PhD, and colleagues at the University of Illinois at Chicago.

And only 13% of states required that students get the recommended 150 minutes a week of physical education, Slater and colleagues reported online in Archives of Pediatrics & Adolescent Medicine.

Despite the lack of strong state policies, Slater and colleagues reported, 69.9% of the 1,761 schools in the sample reported daily 20-minute recess periods.