A new study found that sleeping late at night may have an impact on bodily changes, particularly, weight gain. With this, people who are conscious of their waistline may have to think twice before engaging in late bedtime routines.
Researchers from the University of California, Berkeley and Columbia University aimed to find a link between bedtimes and Body Mass Index (BMI) among individuals in their adolescent and adulthood stages using data that represent national samples.
BMI is a measure of body fat and is obtained by first identifying the height and weight of an individual in kilograms and meters respectively. The weight is then divided by the square of the height to get the final result. A normal BMI among adults range from 18.5 to 24.9.
The authors reviewed three groups of information from the National Longitudinal Study of Adolescent Health, which contains BMI and bed times of 3,342 individuals from 1994-2009.
The findings of the study, showed that later average bedtime in terms of hours during a workweek was linked to a rise in BMI over time. These results were applicable in both teenagers and adults.
The findings remained the same even after the authors controlled the baseline BMI value and the demographic data of the participants. The effects were also evident in those who sleep for a full eight-hour duration.
The factor that the authors noted to have a significant impact in the results is the consumption of fast food. In the long-term, fast food partially mediated the association between sleep times and BMI. This finding was declared by the researchers alongside the confirmation that frequency of physical workout, television screen time and sleep duration did not weaken the association between BMI and workweek bedtime over a period of time.
The authors admitted that their investigations exude some limitations. For one, the sleep data they reviewed were based on self-reports. Also, the researchers were not able to collate information regarding the participants' full diet details.
In the end, the authors led by Lauren Asarnow, a doctoral student from the University of California, Berkeley, concluded that the findings of their study emphasize that bedtimes may be a possible focus of weight management programs during teenage years and as people transition into adulthood phases.
The complete study was published in the October 2015 issues of the journal Sleep.
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