Lack of sleep in kids linked to cravings and obesity
BY JULIE SEAMERFRIDAY, DECEMBER 21, 2007
Increasing evidence indicates that there is a link between sleeping habits and weight gain.
Studies in this area have been conducted over many years. Now that we are facing a world-wide obesity epidemic, affecting both adults and children, the results of these studies that point to contributing factors, should no longer be overlooked.
Where's the link? And how can sleep reduce fat?!
According to one UK study, when sleep deprived the body undergoes hormonal changes which can lead to cravings for sugar and starchy food. Other studies show that short-term sleep deprivation of 4 hours per night, for approximately 1 week, create alterations in appetite regulation. More specifically, sleep lack significantly reduces the anorexigenic hormone leptin and significantly elevates the orexigenic hormone ghrelin. The result is increased self-rated hunger and appetite 1. These key factors may, in part, mediate the development of obesity – particularly in children.
Sleep loss also elevates the stress hormone cortisol. This hormone is lipogenic, meaning it stimulates the body to make fat. Sleeplessness disrupts human growth hormone – a biological necessity which contributes to fat loss, when in balance.
Investigations into sleep and metabolism have noted a relationship between sleep loss and insulin resistance. Acute total sleep deprivation decreases glucose tolerance and creates a pre-diabetic type of muscle metabolism. Even short-term partial sleep restriction has this tendency. When healthy subjects were allowed to sleep for only 4 hours per night for 6 days, they developed glucose intolerance and insulin resistance 2. These metabolic alterations were reversed after sleep recovery.
In relation to young people, researchers have found that up to a third of 12-16 year old only slept between four and seven hours a night which isn't adequate for growing bodies. While adolescents are a population at particular risk because they physiologically require at least 9.2hours sleep per night 3, yet most are getting significantly less 4, children under 10years also experience the effects of short sleep duration 5-8.
While it seems averse that a key to remaining slim is to remain sedentary, experts are now calling for sleep to be taken as seriously as diet and exercise in the fight against obesity. Studies show that kids who get less than eight hours sleep have a higher rate of obesity than those who get a full 10 hours of sleep.
Behaviours that contribute to lack of sleep among children are playing electronic games, using mobile phones in the bedroom at night, lack of physical activity during the day, and watching too much television. Many children are pushed to take on extra-curricular activities, giving them little time to rest after school, creating a form of hyperactivity that contributes to insomnia. On school nights it's been shown that adolescents lose as much as 120 minutes of sleep nightly, and consequently increase weekend sleep time to compensate. However this doesn't rectify the problem. Even kindergarten children are getting 30 minutes less sleep per night, on average, than they did 30 years ago. Our hectic society affects people of all ages!
How can we encourage kids to balance their lives for better rest at night, and therefore have less risk of becoming overweight? Naturally, nutrition plays a key part. Foods high in the amino acid tryptophan may help. Tryptophan is essential for the production of serotonin – the neurotransmitter that creates feelings of calm, which can contribute to sleepiness. Sources include dried fruits, nuts and bananas.
Calcium and Magnesium are also key minerals involved in relaxing all muscular activity. The old wives tale of drinking a glass of milk at night was not completely without merit, because milk is high in both these nutrients. However therapeutic doses in either tablet or powder form are best (and are devoid of calories!), taken with dinner and half an hour before retiring if still restless. For child-specific supplements, a Naturopath, Chemist or Doctor can help you obtain powdered or liquid minerals, for easier administration and correct dosage.
It is also important to ensure children don't eat dinner too late, and stay away from caffeine in the later parts of the day and evening. Research by the Victorian Cancer Council shows that children who watch more than three hours of television each day are significantly less likely to meet their nutritional requirements or be physically active – both contributors to obesity. During day-light savings make the most of evenings and share a gently family walk after dinner, or get some fresh air out in the yard before bed time. If that means you're all watching less television, it certainly won't hurt.
The emerging science on sleep strongly indicates that insufficient sleep is associated with impairments in performance, cognitive function, health and quality of life, including obesity. The effects of sleep loss are cumulative and sleep is a biological imperative. Strangely, we tend to consider it strength to push ourselves, rather than succumb to slumber. If there were ever a time to ensure your whole family, including the kids, keep active throughout the day, eat well, and bunk in early, for a replenishing night's sleep, it's now!
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