Recent studies have discovered a strong link between the children ability to learn, their weight and facing sleep difficulties. These three factors have the power to influence each other.
The hypothesis of the study was that having hard time to learn for some children comes from not getting enough sleep and from being overweight. This hypothesis works also vice-versa, learning difficulties being able to put children at a higher risk for obesity and sleep problems.
The study was applied on 351 elementary school children with an average age of 8. It is one of the first studies to use so young children and also one of the first to analyze the interaction between these 3 factors: lack of sleep, intelligence and obesity.
Before this research there was proven and widely accepted that a very important factor in increasing the risk for sleep apnea and for sleep-disordered breathing is obesity.
With an ever-increasing number of studies finding a direct connection between sleep deprivation and weight gain, its difficult to deny the cause-and-effect relationship. People who get at least seven hours of sleep per night tend to have less body fat than people who dont. Hormones are the likely culprits. Normal adults need seven to nine hours of sleep per night, particularly deep sleep and REM (dream) sleep. When we dont get the good quality and proper quantity of sleep, hormone levels are altered, plus we wake up feeling unrested.
Studies have shown that when sleep is restricted, the hormone ghrelin increases and the hormone leptin decreases. Ghrelin tells our brain that were hungry, while leptin tells it weve eaten enough.
In other words, when we dont get enough sleep we feel hungry, even if weve eaten enough.
In another study, healthy young volunteers showed signs of prediabetes when they were restricted to four hours of sleep for six nights in a row.
The stress hormone cortisol also surges when were sleep-deprived. When that happens, we crave high-fat, high-carbohydrate foods (comfort foods) to increase our serotonin levels to calm down,
Also, the negative influence of lack of sleep on learning has been shown and explained.
Analyzing the link between the three factors is complex. So far sleep problems have been overlooked in children with weight and learning difficulties.
The children who took part in the study developed by study researcher Karen Spruyt, PhD, of the University of Chicago Pritzker School of Medicine had no diagnosed learning problem and none was under ADHD treatment.
A part of the study was based on analyzing traits associated with learning in children: memory, working memory, attention, problem solving and planning, through standard intelligence testing. Secondly, they were evaluated for sleep-disordered behavior in a laboratory.
In order to get the results on the interaction between the three factors, the researchers used a widely known method called structural equation modeling. This model showed that the lack of sleep lowered the scores on learning ability tests and increased his risk for obesity. Also, it was shown that low ability scores had an influence on risk for sleeping disorders and obesity. Thirdly, obesity proved to be a key factor in increasing the risk for breathing-related sleep difficulties and lower learning scores on the tests.
Despite these results, as the research in this field is at its beginning, scientist cannot say firmly that there is a dependence between intelligence, obesity and sleep as there are also overweight children with no learning difficulties and normal weight children with sleep or learning problems.