Longer sleep time and earlier weekday bedtime are associated with better insulin sensitivity in obese teens, reports a new study. The findings of the study are published in The Journal of Pediatrics.
Researchers at Children's Hospital Colorado (Children's Colorado) have identified a connection between overweight and obese teens' sleep health and their insulin sensitivity.
In what is believed to be the first study to use an objective measurement of circadian rhythm salivary melatonin to examine associations of sleep health with insulin sensitivity in adolescents, researchers found that shorter sleep duration, later weekday bedtimes and later circadian timing of sleep were associated with reduced insulin sensitivity in a cohort of adolescents with overweight/obesity during the school year.
"Knowing that traditional weight management interventions, in general, tend to be less effective for adolescents, we sought to look at alternative prevention and intervention measures, including how sleep health might play a role," continued Simon. "Though a connection between short and delayed sleep and insulin resistance has been demonstrated in adults, it had not been studied extensively in adolescents."
Thirty-one adolescents between the ages of 14 and 19 with a body mass index (BMI) in the 90th percentile or higher for their age/sex were recruited for the study from Children's Colorado's weight management and other specialty clinics. Participants wore an actigraphy monitor, a watch-like device worn on the wrist that measures sleep duration and timing, for one week. After seven days, fasting labs and a three-hour oral glucose tolerance test were used to measure participants' insulin sensitivity. They also stayed overnight at Children's Colorado's Clinical and Translational Research Center and provided saliva samples regularly to measure melatonin levels, a marker of circadian rhythm. Participants were in dim light throughout the visit to avoid the impact of light exposure on melatonin.
Study results showed that, when comparing participants who slept less than 6.6 hours per night with those who slept at least 6.6 hours per night, the participants with more sleep had better insulin sensitivity. When analyzing melatonin and insulin sensitivity, better alignment between measures of circadian rhythms and actual bedtimes and waketimes was also associated with better insulin sensitivity.
Although further research is needed to understand better the physiology underlying these observations, the study indicates the potential for sleep and circadian interventions or delayed school day start times as recommended by the American Academy of Pediatrics as a possible means for improving metabolic health for this population.