Later bedtime increases teen girls’ body fat: Experts

ANKARA 

A new study suggests teen girls who prefer to go to bed later are more likely to gain weight than same-age girls who go to bed earlier.

The News Medical Life Sciences website reported a total of 807 teens (418 girls, 386 boys) were part of the study which asked questions about sleeping habits and tracked respondents' movements.

Researchers also calculated the difference between weeknight and weekend bedtimes to estimate their social jet-lag.

“For girls, staying up later was associated with an average 0.58 cm (0.22 inches) increase in waist size and a 0.16 kg/m2 (0.35 pounds) increase in body fat. Each hour of social jet lag was associated with a 1.19 cm (0.46 inches) larger waste size and a 0.45 kg/m2 [0.99 pounds] increase in body fat,” the study found out, according to News Medical Life Sciences.

“Although the researchers found slight associations between these measures and waist size and body fat in boys, they were not statistically significant,” it added.

Previous studies found that adults who preferred to stay up late and had high social jet lag were more likely to gain weight than those who went to be earlier and did not have social jet lag, said experts.

“The researchers undertook the current study to determine if the same associations would be seen in young people,” the report said.

“The researchers concluded that improving sleep schedules may be helpful in preventing obesity in childhood and adolescence, especially in girls,” it added.

The study conducted by researchers at Kaiser Permanente in Oakland, California, and other institutions appear in the JAMA Pediatrics journal published by the American Medical Association.