Sleep Duration and Adolescents' Fat and Carb Intake

Another article in the September edition of the Journal Sleep is about how short sleep durations can change the dietary habits of adolescents. The authors begin by pointing out the lack of data quantifying sleep duration and caloric intake. There is an association between sleep loss and obesity, especially in adults. The question is if it's due to increased caloric intake, decreased physical activity, or the same diet, but just altered metabolism.

The researchers measured sleep times in older adolescents with a watch-like device called actigraphy, which can measure sleep at home. They did this during the weekdays only, as weekend sleep times were too variable. They asked the adolescents to recall what food they had eaten, the portions, the percent of fat and carbohydrate, and snacking. They defined short sleepers as getting less than 8 hours of sleep, which is one hour less than the recommended 9 hours per night for adolescents.

The results showed that the average sleep time was 7.55 +/- 1.14 hours and 34% slept at least 8 hours per night. The median caloric intake was 1917 calories, 51% carbs, and 35% fat. If an adolescent slept <8 hours per night, they tended to be obese rather than non-obese. Also, if the adolescent slept <8 hours per night, they had a 2.7% increase in fat consumption and a 3.7% decrease in carbohydrate consumption than those that slept >8 hours.

Those that slept <8 hours / night had a 2.1 fold increase in the odds of eating a high-calorie snack. For each 1 hour increase in sleep duration, the odds of a high-calorie snack decreased by 21%. This was most prominent in girls.

The authors acknowledge the small differences in fat and carb intake, but point out that small increases tend to accumulate and could increase obesity rate.

As I've said in another post, childhood obesity is not caused by short sleep duration. In my opinion, people who sleep less and are obese have extra weight because they have more wake time to eat. Obestity is caused by increased consumption of high-calorie foods rich in salt, sugar, and fat. The food tastes good, so kids eat it, and eat lots of it. They also don't exercise much, as our society is so sendentary. And thinking that if you get an extra hour of sleep, you can magically shed extra weight without serious dietary change is unrealistic.

Insomnia, Sleep Duration, and Mortality

In the September edition of the Sleep Journal, there is an article about the association of insomnia, sleep duration, and insomnia. The authors followed adult men and women to assess death rates. The study participants were assessed with a comprehensive sleep history and physical exam and one night in the sleep laboratory. Insomnia was defined subjectively as an insomnia complaint that lasted for one year. Sleep duration was defined as short if it lasted less than 6 hours per patient's report.

The results showed that in men, the mortality rate was increased for insomniacs with short sleep duration and this was independent of age, race, obesity, alcohol consumption, smoking, obstructive sleep apnea, or depression. The effect was not mitigated by the presence of high blood pressure or diabetes.

There was no increased mortality in women, whether or not they were short sleepers or had insomnia. Also, the association with sleep duration was only for the subjective report, and not based on the duration of sleep measured objectively in the sleep lab.

This study purports to be the first one to link insomnia with mortality. However, the average follow up was 14 years in the men, meaning their sleep study was done at a time when only airflow was routinely monitored. This means that nasal pressure transducers were not used, and therefore sleep apnea could have been present in these men. Sleep apnea is more prevalent in men which could explain why the mortality rate was increased for men and not women.

I'll concede that some patients with insomnia can have a revved up nervous system, referred to as hyperarousal. This, theoretically, could increase cardiovascular disease. But the results of this study do not prove that insomnia by itself increases mortality. Objective monitoring of sleep duration at home over extended periods of time will help answer this question more completely.

Zeo and Insomnia

I've had a few patients with insomnia try the Zeo. I've even tried it myself. For those unfamiliar, the Zeo is an EEG monitor worn around the head like a headband while trying to sleep. The device will analyze EEG patterns and display your sleep stages for you to review.

I found the headband comfortable enough and the report interesting. I can see where the Zeo could be helpful in some patients. For example, I've had some tell me how their sleep stages changed in response to medication adjustments I made. Some slept deeper or had less dream sleep. I could also see the Zeo help people understand that they might be sleeping more or better than they think they are, as all of us have an imperfect perception of our sleep duration.

The Zeo could also cause more focus on getting the "gold standard" eight hours of sleep per night. I could see some insomniacs becoming more anxious because the Zeo only confirms that they are not sleeping as well or as long as they think they should.

I could see the Zeo being an important tool for diagnosing other sleep disorders in the home as well, especially sleep apnea. A Zeo along with a portable device to measure breathing would be helpful. The entire area of ambulatory monitoring is very exciting to me, as it opens up the possibility of measuring sleep over multiple nights in a patients home environment.

Sleep duration and obesity in children

There was an article by NPR about a recent study published in the Archives of Pediatric and Adolescent Medicine. The researchers surveyed 2000 children about their sleep duration and measured the children's weight over a five year period.

The researchers concluded that children who slept greater than 10 hours per night were less obese than those that slept less than 10 hours per night. Napping during the daytime did not help, implying that nighttime sleep duration is the more important factor. The effect was most prominent in infants and toddlers. The authors of the study hypothesized that children who do not get enough sleep would be too tired to exercise. Also, certain hormones that control appetite can be affected by sleep duration, but this has only been proven in adults.

The article author at NPR lead off the story by stating that in infants and pre-schoolers, a good and long nights sleep may be just as important as diet and physical activity with regards to obesity! This is highly misleading, in my opinion. It takes the focus off the real problem with childhood obesity, which is their poor diet. If it only were that easy - just get more sleep and your overweight child will be thin again. The problem with this study is that it is dependent on parents' report of sleep duration, which is frought with uncertainty. Also, it could be argued that parents who let their children stay up late probably also let them eat too much junk food. I wish the authors of the study had surveyed caloric intake along with sleep duration in these children.

Don't get me wrong. Sleep is very important to kids' physical, emotional, and cognitive development. And too little sleep could play a small role in weight regulation. But lets focus on the real problem with childhood obesity rather than on these minor issues.

How Do You Expect Me To Sleep With All That?

When I ask a patient to undergo a sleep study, I explain to them what is involved so that they can prepare properly. Most of my patients don't mind spending one or two nights away from home. In fact, it's like going to a motel for the night. But I explain that I need to monitor their sleep with multiple wires - on their scalp, face, neck, chest, abdomen, finger, and legs. I imagine some patients immediately think of Pinhead from the movie Hellraiser.



I explain that the sleep study uses no needles, and there will be no pain or blood involved in the process. I let them know that all of the wires are put on with glue, tape, or velcro. I find it helpful to show them a picture of a patient that has the wires placed, so that they can visualize the process.



When patients see the picture, most of them ask, "How do you expect me to sleep with all of those wires on me?" I tell them that almost everyone sleeps on the sleep study. And it's not crucial that I get 8 hours of solid sleep to be able to make a diagnosis. I ask the patient to just do their best - and they usually do.