Currently, much attention is focused on the obesity epidemic in the United States, including an alarming rise in childhood obesity. A new study has found an association between child obesity and decreased hours of sleep. The findings were published online on November 4 in the journal Pediatrics by researchers at the University of Rhode Island, Indiana University, University of Tennessee, and Children’s National Medical Center in Washington DC.
The researchers designed a study to evaluate the effect on children’s sleep duration. The data was derived from self-reported food intake and measured weight. The investigators also measured the levels of leptin and ghrelin, which are appetite-regulating hormones. Ghrelin is a hunger-stimulating hormone that is produced mainly by stomach and pancreatic cells. Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of leptin, which is a hormone produced by adipose (fatty) tissue; leptin induces satiation (a feeling of fullness when present at higher levels.
The study group comprised 37 children. Aged 8 to 11; 27% of the children were either overweight or obese. During the first week, the children slept their typical amount at home for one week. During the second week, half the children decreased their bedtime by 1.5 hours for one week. During the third week, the other half of the study group decreased their bedtime by 1.5 hours, while the remainder resumed their normal sleep interval. The children were required to daily report what they ate during the past 24 hours. They were also subjected to food reinforcement, meaning that they earned reward points for eating healthy foods. Each morning, fasting levels of leptin and ghrelin were measured. In addition. They were weighed.
The researchers noted that the children experienced a 2 hour, 21 minute difference in their sleep duration (the difference between the increased and decreased sleep interval). During the period when the children slept longer, they consumed on average 134 less calories per day; in addition, their fasting leptin levels were lower. The longer sleep period also resulted in a 0.22 kilogram (0.5 pound) decrease in weight. However, no difference was found in fasting ghrelin levels or food reinforcement.
The authors concluded that increased sleep duration among school age children resulted in decreased reported food intake, a decrease in weight, and lower fasting leptin levels. They recommended that further study should be conducted in regard to sleep duration and child obesity.
Take home message:
This is a valid study in that the children were randomized to sleep less for one week; then the two groups were switched in regard to sleep intervals. However, the study is limited by the small number of subjects and short duration of study. Thus, a larger period, for a longer period of time should be conducted. Meanwhile, make sure that your kids are getting an adequate sleep period each time. In addition, an adequate amount of sleep might help mom and dad shed those extra pounds.