According to a new study, going late at night to sleep could be linked to weight gain over time. Scientists analyzed data taken from more than 3,300 teens and young adults during 15 years. The study was published in the journal Sleep this October, and it was made by UC Berkeley.

Data was taken from the National Longitudinal Study of Adolescent Health, which has been studying teenager behaviors in the U.S. since 1994. They focused on puberty, college years and young adulthood, according to a Berkeley press release.

Xiao Hao Guangdong 4-year-old little chubby’s weight is over 60kg. Credit:

The study reveals that every hour people went to bed late, there was a 2.1 increase in BMI (body mass index). This index is calculated based on weight and height of the person. Also, researchers added that exercise, total sleep time and recreational time involving sedentary activities like watching tv didn’t affect the results.

A healthy BMI range is estimated to be between 18.5 and 24.9. A BMI of 25 to 29.9 is considered overweight, while a BMI of 30 or greater constitutes obesity, according to information provided by The National Institutes of Health, CBS News says.

“Obesity is obviously growing among adolescents and adults, and there’s also an epidemic of lack of sleep and later bed time preference in teens,” study author Lauren Asarnow, a doctoral candidate at the University of California, Berkeley, told CBS News.

According to the Center for Disease Control and Prevention, more than 30 percent of the U.S. kids and adolescents are obese, and it is related to other conditions like heart diseases and diabetes.

Bedtime management in adolescents is crucial to weight management, the researchers say. “Conceivably, if you’re going to bed an hour later, over time you could be shifting BMI categories from normal to overweight,” Asarnow said. “So even a two-point increase could be clinically significant,” according to CBS News.

Scientists believe that this results could be related to the fact that the more late you stay awake, the more vulnerable you are to eat junk food at nights and skip the day breakfast, a behavior associated with weight gain. Also, they point out that it could affect the metabolism.

According to Tech Times, “the American Academy of Sleep Medicine recommends that teens get a little over nine hours of sleep at night”, although statistics prove that adolescents don’t follow that advice.

“The good news is sleep is a highly modifiable [activity],” she said. “If you could shift bedtime in the teenage years, you can create good sleep habits and maybe prevent weight gain over time”, Asarnow concludes on the study according to CBS News.

Source: UC Berkeley