Teens who regularly sleep late on weeknights have a higher risk of weight gain in comparison to their peers who sleep more normal hours according to research by a team from UCLA.
The study is the first of its kind to find a link between the time of sleep and weight gain among teenagers and even adults that are healthy. The results of the study were published in the October issue of the journal Sleep.
The study found that exercise, screen time, and the number of hours teenagers slept did not mitigate the rise in BMI. BMI (body mass index) is the measure of a person’s weight in kilograms divided by the square of height in meters. A healthy adult BMI range is estimated to be between eighteen and twenty five.
Data from the National Longitudinal Study of Adolescent Health, which has tracked the influences and behaviors of U.S. teenagers since 1994 was analyzed by he study, mainly looking at three time periods, the onset of puberty, young adulthood and college-age years, the study compared the bedtimes and BMI of teenagers from 1994 to 2009.
The results of the study suggest that adolescents who go to bed earlier will “set their weight on a healthier course as they emerge into adulthood,” Asarnow said. Adolescents in the study reported their bedtimes and sleep hours while researchers monitored their BMI.
The researchers analyzed longitudinal data from a nationally representative cohort of more than 3,300 youths and adults, and found that for every hour of sleep they lost, they gained 2.1 points on the BMI index, a significant increase that usually took place over a period of five years.
“These results highlight adolescent bedtimes, not just total sleep time, as a potential target for weight management during the transition to adulthood,” said Lauren Asarnow, lead author of the study and a doctoral student in UC Berkeley’s Golden Bear Sleep and Mood Research Clinic.
Surveys show that many teenagers do not get the recommended nine hours sleep a night, and report having trouble staying awake at school. The human circadian rhythm, which regulates physiological and metabolic functions, normally switches to a later sleep cycle at the onset of puberty.
According to an article from the Sleep Foundation, teens tend to have irregular sleep patterns during a week, they typically stay up late and sleep in late on the weekends which can affect their biological clocks and hurt the quality of sleep. Many teens suffer from treatable sleep disorders, such as narcolepsy, insomnia, restless legs syndrome or sleep apnea.