More time in gym class cuts likelihood of obesity

Increasing the amount of time elementary school students spend in gym class reduces the probability of obesity, said a study posted online May 9 in the Journal of Health Economics.

Adding 60 minutes of physical education in school per week decreases the risk of obesity among fifth-graders by 4.8%, the study said. There was no evidence that more time in gym class negatively affects academic achievement test scores.

The study represents some of the first evidence of a causal effect of PE on childhood obesity, researchers said. They found, however, that while increasing time in gym class reduces weight among boys it had no significant effect on girls. One possible reason for that difference is that more PE time tends to increase boys’ physical activity levels outside school, such as in organized sports, but often results in girls watching more TV at home, said the study (link). Future studies should further examine that issue, researchers said.

Researchers assessed state policies on elementary school physical education and examined data from the Early Childhood Longitudinal Study, Kindergarten Cohort for 1998-2004. That sample of children was followed from kindergarten (1998-99) through fifth grade (2003-04).

All schools should provide students access to at least 60 minutes per day of vigorous or moderate-intensity physical activity, more than half of which should be accomplished during school hours, said an Institute of Medicine report issued May 23 (link).

The IOM recommends that elementary school students spend an average of 30 minutes per day in physical education class, and middle and high school students spend an average of 45 minutes per day in PE. Other opportunities for physical activity could include recess, academic lessons that require students to move around and promoting biking or walking to school, the report said.