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A new study led by researchers from the General Hospital of Children of Massachusetts (MGHfC) and Harvard Medical School has found that preferences and patterns of synchronization of the sleep of adolescents should be considered risk factors for obesity and the health cardiometabólica, and that the effects are greater in the girls than in the guys.

it Is known that the poor quality and short sleep duration increases obesity and cardiometabolic risk in children. However, what has rarely been studied is how the sleep time and the own preferences of teenagers about when to sleep and participate in other activities that may influence their risk of obesity and poor health cardiometabólica.

“beyond the quality and quantity, time is a vital component of the dream, because it determines whether the circadian clock of an individual, the internal time of the sleep-wake cycle is synchronized with the rhythms of their daily activities ,” says Elsie Taveras, chief of the Division of Pediatrics at MGHfC and the lead researcher of a new study published in “JAMA Pediatrics”.

“This is particularly important for adolescents whose preferences night-time and academic demands often result in hours of irregular sleep that can cause a misalignment circadian”, he adds. “Our research found that the “owls” night owls, teenagers who prefer going to bed late but have to get up early to go to school, had an increased waist circumference and increased abdominal adiposity that the “larks of morning”, those who prefer to go to bed early and get up early to start their day.”

The researchers emphasized the need of consistent patterns of sleep-wakefulness during the week, including weekends, to reduce the risk of obesity and promote the health cardiometabólica.

The research team studied 804 children who were part of Project Viva, an innovative cohort study initiated 20 years ago by researchers at the Harvard Pilgrim Health Care Institute that followed mothers and children from the Boston area to characterize the factors from early life that influence the long-term health.

The importance of biological clocks

the scientists examined The cronotipos (preferences evening versus morning), and the “jet lag “social” (differences in hours of sleep between school and free days) in children 12 to 17 years of age. The cronotipos night and the greater jet lag social is associated with a greater adiposity .

“A great variability in patterns of sleep during the week can alter the normal physiology, resulting in obesity and cardiometabolic risk,” says lead author Elizabeth Cespedes Feliciano, formerly in the School of Public Health at Harvard Chan and is now a research scientist at the Kaiser Permanente Division of Research in Northern California.

“Our study supports the importance of biological clocks to influence the risk of obesity. We observed stronger associations with adiposity for girls compared to boys. Although the reasons for this difference are not fully understood, may include influences biological and socio-cultural , ” explains Feliciano.

According to the researchers, to help teens address the effects of the cronotipos and the social calls of “jet lag” for family initiatives, clinical and community. “Families should encourage consistency in the sleep schedules of their children and schedules of bed and wakefulness, as well as improvements in their sleep hygiene by limiting the electronic media and the use of caffeine in the evening,” says Feliciano.

schools can also play an important role in the enact policies that delayed the start times of the morning and by facilitating students to spend time during the school day to academic activities or sports that you are shedding each time more in the evening, says Taveras.

In his words, from a clinical point of view, doctors should begin to include cronotipos and “jet lag” social in its preventive advice. “You should be aware of laimportancia to encourage adolescents to follow sleep schedules constants on weekdays and weekends. Adolescent girls and the “owls” can take advantage especially of keep sleep schedules consistent”, he concludes.

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