Sleep and Obesity

In my latest child care book, Obesity Prevention for Children: Before It’s Too Late: A Program for Toddlers and Preschoolers, I discuss the interesting relationship between sleep and obesity. Quoting from the book:

“You would think that a child who slept less and stayed up longer would be burning more calories, and would therefore have less of a chance to become overweight. Wrong! Just the opposite is true. Poor sleep habits have been proven to be associated with childhood obesity. A study of preschool children found that those who slept less than 8 hours per night had an increased rate of obesity, and that the risk of obesity increased as sleep time decreased. Another study showed that children who slept less than 9 hours a night had 1.5 times the risk of being obese as compared to the children who slept more than 11 hours each night. A large-scale study of 7,000 3-year-old children concluded that sleeping less than 10.5 hours each night was associated with obesity at 7 years of age.”

I recall discussing the relationship between sleep and obesity with the mother of 3-year-old Rebecca. “It doesn’t make any sense, Dr. Eden. If Becky sleeps less, she will have more time to run around and burn up calories.” I had to explain to her that it just doesn’t work that way.

The exact reason for the association of sleep and obesity has not been proven as yet, but the correlation itself is a fact. One very interesting study from the University of Illinois identifies sleep duration as one of the most important risk indicators for obesity. 

In another study, 329 parent/child pairs were evaluated to determine the greatest risk factors in developing obesity (the children were 2-5 years old). The results showed that there was a 2.2 times greater risk of becoming overweight or obese among children who slept 8 hours or less each night. The conclusion to be drawn by this investigation and others suggests that early childhood is the developmental period when sleep behavior, particularly lack of sufficient sleep, increases the obesity risk.

So: how much is enough sleep for your preschooler? According to the American Academy of Pediatrics, 2-5 year olds require a minimum of 11 hours per day. Children who meet this requirement lower their risk for obesity.

But some preschoolers are better sleepers than others. Many resist bedtime, figuring out all sorts of ways to stay up. This is perfectly normal behavior; just remember that adequate sleep is very important, not only in relation to obesity, but also to prevent fatigue during the day. Insufficient sleep can impair cognitive functioning and increase behavior problems. (The sleep deprivation I suffered during my pediatric residency days made me a pretty cranky fellow most of the time, according to my wife, but what is my excuse these days?)

A number of behavioral and environmental factors may contribute to inadequate sleep. Among the most common are:
1.      Irregular bedtime and wake time
2.      Inappropriate napping habits
3.      Vigorous physical activity close to bedtime
4.      Noisy or un-darkened sleep environment
5.      TV in bedroom

(Again, we strongly advise that you never put a TV in your young child’s bedroom. Not only will it act as a deterrent to a good night’s sleep, but it helps lead to child obesity, independent of the total TV viewing time.)

Your job is to create an environment conducive to ensuring sufficient sleep. This means a cool, quiet, dark room – without a TV. A dark room is very important; melatonin, the brain’s neurotransmitter which regulates the sleep/wake cycle, is triggered by darkness and makes people drowsy. TV has a spectrum of blue light that is a potent suppressor of melatonin, and can easily disrupt sleep schedules. Try to avoid active physical activity for at least one hour before bedtime. I know that this is often difficult to achieve, but do the best you can. A regular bedtime routine or ritual is a must. How about a warm bath, reading a story, a good night hug and kiss, a tuck in, and lights out? The nature of the ritual is up to you; what is important is that you are consistent each night. Your preschooler must learn to fall asleep without you around.

I didn’t follow my own advice when our son was four years old. Often tired myself, I would lie down in his bed next to him to wait for him to fall asleep. Bad idea; I usually fell asleep first!