For many people, adolescence and early adulthood is a period filled with late nights and partying. But a new study suggests these late nights may have negative implications for weight management.
Published in the journal Sleep, the study found that the later a teenager or young adult goes to bed on weekdays, the more likely they are to gain weight over time.
The research was conducted by lead author Lauren Asarnow, of the University of California-Berkeley, and colleagues from Columbia University in New York, NY. It is the first observational study to assess the link between bedtimes and body mass index (BMI) among any age group.
According to the National Sleep Foundation, teenagers aged 14-17 should be getting around 8-10 hours of sleep each night, while young adults aged 18-25 should be getting around 7-9 hours of sleep each night.
However, a report from the Centers for Disease Control and Prevention (CDC) reveals that only 31% of high school students report getting at least 8 hours of sleep a night, while almost 30% of adults report sleeping fewer than 6 hours nightly.
It is well known that lack of sleep can affect health. Last month, Medical News Today reported on a study claiming that not getting enough sleep can raise the risk of catching a cold, while another study links inadequate sleep to early signs of heart disease.
For this latest study, Asarnow and colleagues set out to establish whether there is a relationship between the time a person goes to bed and the risk of weight gain.
The team analyzed data of 3,342 youths and young adults who were part of the National Longitudinal Study of Adolescent Health from 1994-2009.
Each participant reported their weekday and weekend bedtimes at three time points: during the onset of puberty, college-age years and young adulthood. Their researchers calculated the BMI of participants at each time point.
The team found that the later an individual’s bedtime between adolescence and young adulthood, the more weight they were likely to gain over a 5-year period; for every hour later a participant went to bed, an increase in BMI of 2.1 kg/m2 was identified.
The researchers were surprised to find these results remained even after accounting for participants’ total sleep duration, screen time and physical activity levels.
Commenting on the findings, Asarnow says:
“These results highlight adolescent bedtimes, not just total sleep time, as a potential target for weight management during the transition to adulthood.”
She adds that teenagers should go to bed earlier in order to “set their weight on a healthier course as they emerge into adulthood.”
Earlier this year, MNT reported on a study published in the journal Pediatrics that found the amount of sleep teenagers are getting each night has fallen over the past 20 years.