The obesity pandemic is claiming its presence even among youngest of children and is clearly on the rise. The potential interrelationships between sleep and obesity have gained recent attention.
A new study published in Pediatrics, the Journal of the American Academy of Pediatrics, said young children who skimp on sleep both during the week and on the weekends may be at an increased risk of becoming obese.
According to lead researcher Dr. David Gozal of the University of Chicago in Illinois, children who sleep the least could be four times more likely to develop an unhealthy body weight.
"If a child has a tendency to be obese but gets adequate sleep, he is more likely to be protected than if he is not sleeping as much as he needs. Catch-up sleep is better than nothing and can help, but we don't think it can offer complete protection."
For the study, researchers used a special sleep monitoring bracelet on 308 children in Louisville, Kentucky.
Before the study the young subjects were identified as normal, overweight, or obese based on their body mass index (BMI) scores, a measure of body fat based on height and weight. They followed the group, which ranged in ages from 4 to 10 years old, for one week.
Children slept 8 hours per night, on average, regardless of their weight categorization. A nonlinear trend between sleep and weight emerged.
For obese children, sleep duration was shorter and showed more variability on weekends, compared with school days. For overweight children, a mixed sleep pattern emerged.
Fasting morning plasma levels of glucose, insulin, lipids, and high-sensitivity C-reactive protein also were measured for a subsample. Obese children whose shorter sleep duration and more-variable sleep wake timing had the unhealthiest blood profiles.
Parents, and doting grandparents, here’s enough reason to enforce your little one's bed times or risk obesity and metabolic dysfunction.
BMI for children and teens? Click here to find out how BMI is calculated and interpreted.Journal Reference:
Karen Spruyt, Dennis L. Molfese, and David Gozal. Sleep Duration, Sleep Regularity, Body Weight, and Metabolic Homeostasis in School-aged Children. Pediatrics 2011; 127: e345-e352. Click here to download the full paper.
The researchers believe that lack sleep contributes to obesity by wreaking havoc on metabolism and the endocrine system -- and this is especially true when the body is young and still growing. Dr Gozal said there are numerous studies where sleep deprivation has been shown to disrupt levels of gherlin and leptin, two hormones which regulate hunger and appetite. When the body craves sleep, it interprets it as hunger causing leptin levels to crash and ghrelin levels to spike; this in turn, seems to trigger overeating and may also signal the body to cling to fat stores more tenaciously.
Other studies indicate that poor sleep can throw off the body's biological clocks -- also known as circadian rhythms -- particularly the clock that regulates glucose and insulin, two hormones that when out of balance, are closely associated with weight gain, heart disease and diabetes. Sleep deficit has also been found to elevate levels of cortisol, a hormone that among other things regulates how the body uses energy; elevated cortisol levels have been linked to insulin resistance and a higher BMI.