A good laugh and a long sleep are the best cures in the doctor’s book, so goes an Irish saying. A recently published study, in the journal Pediatrics, proves that the Irish were unleashing pearls of wisdom when they recommended a long sleep.
The study, headed by a Temple University professor, was an attempt to draw a correlation between the amount of sleep school children have and the children’s weight and food intake.
As you may be aware, childhood obesity has been skyrocketing over the years, and in the US, 17% of children have developed obesity. A confluence of factors, such as super-sized portions, sugary drinks and general inactivity, have been implicated in the surge in the prevalence of childhood obesity. However, the role of other factors, such as the duration of sleep, have not been fully investigated, even though previous studies have often found a causal relationship between sleep and obesity.
The purpose of this study then was to find out how sleep, or lack thereof, could be a contributing factor in childhood obesity.
A Crossover Study
To evaluate the effect that the length of sleep had on food intake, weight, and the hormones ghrelin and leptin (regulators of appetite and craving), the researchers conducted a crossover study.
A total of 37 children, aged between 8 and 11 years, took part in the three week study. 10 of these kids were either overweight or obese at the time of the study.
The children began their first week sleeping on their normal schedules and in the following week, they were randomly assigned to a longer or a shorter sleeping timeframe. The length of time that was added or removed from their normal sleeping time was 1 ½ hours. The crossover happened in the third week, when children who had shorter sleeping times were switched to the longer sleeping time and vice versa.
Throughout the duration of the study, the children reported the foods consumed, and were also weighed. Samples were also taken to determine the levels of ghrelin and leptin.
More Sleep, Less Eaten
There were some interesting observations made from the study. For one, it was found that the children who slept more ate 134 less calories every day. Furthermore, they also weighed 0.5 lbs. less compared to when they slept a shorter while. Of importance too was the fact that leptin levels were found to be lower in them. The amount of leptin in circulation is directly proportional to the quantity of adipose in the body, therefore low levels mean the amount of fat deposits were also low. There were no differences in the level of ghrelin.
The results from this study were thus very clear; by some mechanism, sleeping longer seems to induce a sense of satiation that results in the child consuming less food.
By the way, the importance of proper sleep is not only limited to children; it is also important in adults, as a previous Canadian study has shown that sleep alone could contribute to some weight loss. Furthermore, the lack of it has been shown to be detrimental to proper brain function, including making food choices. A study conducted last year found that sleep deprived individuals would tend to high-calorie foods and were largely incapable of choosing healthier alternatives, due to an impairment of the frontal lobe, the brain region where complex decisions are made.
Moreover, sleep deprivation increases the levels of ghrelin, which is known to stimulate hunger, and a craving for energy rich foods. With these hormone raging, and the brain muddled, one can consume greater than needed quantities of calories without even feeling sated.
So, when it’s bedtime, make sure the child goes to sleep; you are significantly and positively impacting his health by giving him all the sleep he needs.