Among concerns that the obesity epidemic is taking over the U.S. population, a new study highlights the link between weight gain and late bedtime hours.
The study, published in the latest issue of the Sleep journal and led by doctoral candidate with the University of California, Berkeley, Lauren Asarnow, is of outmost importance for teens transitioning into adulthood and young adults.
The main finding of the study relates to the fact that late bedtime hours may lead to a worrying 2.1 points increase in body mass index (BMI).
Thus, the extensive study highlights the link between weight gain and late bedtime hours and spans 15 years of data gathering, from 1994 to 2009. Over 3,300 teens, as well as young adults were included in the study. Over the 15-year timeframe the participants self-reported their bedtime hours, the level of exercise, time spent sitting and fast food consumption. The report came in every five years.
Thus, the three data sets collected over the research period was analyzed in addition to each participant’s BMI calculated at the time of each report. Factors as socioeconomic status, age, sex, ethnicity and race were accounted for.
The results indicated that for each hour added to bedtime hours, the participants’ BMIs increased by over 2 points.
According to Asarnow:
“Conceivably, if you’re going to bed an hour later, over time you could be shifting BMI categories from normal to overweight. So even a two-point increase could be clinically significant”.
What surprised the research team was that neither of factors that would be expected to be linked to the increase in BMI actually seemed to play a role. Neither too much time spent sitting, in front of a computer, a TV or otherwise, nor exercise or lack of exercise thereof impacted BMI. Late bedtime hours were the only factor that accounted for the spike in BMI, associated with increased consumption of fast food or junk food.
The study cannot provide an explanation as to the link between weight gain and late bedtime hours. Yet, according to Asarnow, there some clues are embedded in speciality literature and are related to behavior and metabolic patterns.
The study stems from the Sleep and Mood Research Clinic with the University of California, Berkeley.
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