According to a recent study published online on April 8, 2013, in Pediatrics, more sleep may help to prevent obesity in teenagers.
The researchers recruited students in Philadelphia entering their first year of high school and followed them from age 14 to 18 years until graduation to study changes in body mass index (BMI). Students reported their height, weight, and hours of sleep every 6 months.
An increase of just 1 hour of sleep was associated with a decrease in body mass index, especially in adolescents with higher BMIs. Even after adjusting for time spent sitting in front of the computer and television, the correlation between increased sleep and decreased BMI remained.
The authors suggest that increasing sleep to 10 hours per day at age 18 years could reduce the number of adolescents with a BMI above 25 kg/m2 by 4%.
“One possible solution could be for high schools to delay the start to the school day,” said lead author Jonathan A. Mitchell, PhD, postdoctoral fellow in the Center for Clinical Epidemiology and Biostatistics at Penn Medicine. “Previous research has shown that delaying the start of the school day even by 30 minutes results in a 45-minute per day increase in sleep. Since our study shows increasing sleep by an hour or more could lead to a lower BMI, delaying the start of the school day could help to reduce obesity in adolescents.”