Infants and toddlers who sleep less than 10 hours at night are at high risk of obesity as soon as they reach primary school age. The latest findings by a team of researchers from the Massachusetts General Hospital for Children also confirmed similar evidence from a number of previous studies.
What is the content of the research?
This study processes data that is more comprehensive from the results of face-to-face interviews and continuing questionnaires to mothers and children about children's sleep habits in each age period of 6 months to 7 years. The researcher also considered environmental factors and maternal lifestyle choices, measurements of height and weight of children, as well as total body fat, abdominal fat, lean body mass, and waist and hip circumference of children.
Night sleep deprivation is defined as the duration of sleep less than 12 hours throughout the night for children aged 6 months to 2 years; less than 10 hours a day for children aged 3-4 years; and less than 9 hours a day for children aged 5 to 7 years. Each child's sleep habits from the interviews of mothers are given a sleep score that covers each of these time periods - starting from 0 for children who suffer from chronic sleep deprivation to 13, the best score for the duration of sleep is ideal.
The researchers found that children with the lowest sleep scores had the largest body measurements, reflecting the characteristics of obesity and abnormal body fat deposits for children their age. This association is consistently found in all age categories, so researchers believe that the risk of childhood obesity will remain high and as severe at all ages.
Another study from the University of Washington published in the journal Archives of Pediatrics & Adolescent Medicine found infants and toddlers to age 4 who lack sleep at night, 80 percent more likely to have excess body fat in the next five years than other children who sleep longer. Furthermore, even children who routinely lack sleep at night throughout the school day but manage to make up for a small portion of their sleep on weekends are reported to remain at high risk of obesity - up to three to four times as much. What is the reason?
What does a child lack of sleep with obesity in the future?
Child health observers believe that lack of sleep plays an important role in the blooming of the child's waist line, because it disrupts the body's metabolism and endocrine system.
The condition of lack of sleep causes children to be trapped in a vicious circle where the lack of nighttime sleep causes fatigue during the day. Fatigue makes children hungry so much that they eat more, but are less interested in engaging in physical activity. This leads to a lack of burning of energy, which then leads to obesity, which leads to a return to poor sleep patterns.
Lack of sleep at night disrupts the hormones ghrelin and leptin (two hormones that regulate hunger and appetite) and the body's biological clock, aka circadian rhythm. When the body needs sleep, the body interprets it as hunger, causing the level of leptin to fall while ghrelin levels increase rapidly; this response triggers an overeating pattern and also instructs the body to maintain its fat stores. Then, the circadian clock of a ravaged body will disrupt the regulation of glucose and insulin levels. When these two hormones are chaotic, they are closely related to weight gain, heart disease, and diabetes.
The lack of sleep duration of children is also found to increase cortisol levels, a hormone which one of its functions is regulating the body's energy management; increased cortisol levels have been linked to insulin resistance and higher BMI rates. Other pediatric studies also link bad sleep habits with behavioral problems and learning disabilities.
Then, how long should the child sleep at night?
Regardless of the weight category, the average child in a variety of studies had an eight-hour night's sleep duration during the week - far from the recommendation of 9-10 hours of sleep by the National Institutes of Health and other health groups. The CDC recommends babies aged 1 year to sleep 13-15 hours at night and toddlers aged 3-5 years need 11-13 hours of sleep a night.