Less sleep linked to weight problems in childhood

Chaput JP et al. Relationship between short sleeping hours and childhood overweight/obesity: results form the ‘Quebec en Forme’ Project. International Journal of Obesity. Published online 14 March 2006.

The less a child sleeps, the more likely he or she is to become overweight, according to researchers.

To assess the relationship between short sleep duration and obesity-related variables in children, researchers from Universite Laval, Quebec, collected data from 422 school children aged five to 10. Their weight, height, and waist circumference were measured and the children classified as normal, underweight, overweight or obese, according to body mass index (BMI) per age. Data on the children’s lifestyle and socioeconomic status was obtained through parental phone interviews.

Through BMI measurement, the researchers determined that 20% of boys and 24% of the girls were overweight. Children who slept less than 10 hours a night were 3.5 times more at risk of being overweight than those who slept 12 or more hours. No other factor analysed in the study had as much of an impact on obesity than time spent sleeping.

Hormone production is thought to explain the relationship between sleep and obesity. ‘Lack of sleep lowers the level of leptin, a hormone that stimulates metabolism and decreases hunger’, say the authors. ‘In addition, short nights of sleep boost the concentration of ghrelin, a hormone that increases hunger.