Talk about a win-win deal: A new study suggests that sleeping an additional hour each night may reduce the prevalence of adolescent obesity.
Researchers from the Perelman School of Medicine at the University of Pennsylvania discovered that fewer hours of sleep is associated with greater increases in adolescent body mass index (BMI) for participants between 14 and 18-years-old.
Investigators say the findings suggest that increasing sleep duration to 10 hours per day, especially for those in the upper half of the BMI distribution, could help to reduce the prevalence of adolescent obesity.
Study results are available online in the latest issue of Pediatrics.
Previous studies have shown that a correlation exists between short sleep and obesity, but until now few have been able to rule out other variables such as time spent watching television and being physically active.
In the new study, researchers followed more than 1,000 Philadelphia-area high school students from their freshmen through senior high school years.
At six-month intervals, study participants were asked to report their sleep patterns. At the same intervals heights and weights were reported and BMIs were calculated.
Study authors suggest the results could have far-reaching implications and aid in reducing the high levels of adolescent obesity in the United States.
“The psychosocial and physical consequences of adolescent obesity are well-documented, yet the rate has more than tripled over the last four decades,” said lead author Jonathan A. Mitchell, Ph.D. “What we found in following these adolescents is that each additional hour of sleep was associated with a reduced BMI for all participants, but the reduction was greater for those with higher BMIs.
“The study is further evidence to support that getting more sleep each night has substantial health benefits during this crucial developmental period.”
Importantly, the relationship between sleep duration and BMI remained after adjusting for time spent in front of computer and television screens and being physically active.
This finding led to the conclusion that more sleep could contribute to the prevention of adolescent obesity, even if screen time and physical activity guidelines are met.
Based on the results, the authors suggest that increasing sleep from 8 to 10 hours per day at age 18 could result in a 4 percent reduction in the number of adolescents with a BMI above 25 kg/m2.
At the current population level, a 4 percent reduction would translate to roughly 500,000 fewer overweight adolescents.
“Educating adolescents on the benefits of sleep, and informing them of sleep hygiene practices have shown to have little impact on adolescent sleep duration,” said Mitchell.
“One possible solution could be for high schools to delay the start to the school day. 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.”