Protein, Carbohydrates, and Alertness

There are a group of cells, small but important, in your lateral hypothalamus that contributes to daytime alertness. Loss of these cells is thought to be responsible for the sleep disorder narcolepsy. A group of researchers studied these neurons and the effect of carbs versus protein on their firing rates. They have already shown that carbs inhibit their firing, which could possibly explain 'sugar crashes', where you get sleepy soon after eating sugary foods.

During the current study, the results showed that protein activated the cells, meaning that protein could help keep you awake. Also, protein blocked the effects of sugar on the cells, meaning that you might be less sleepy from eating sugar if you ate it with protein. This makes sense, as diabetics are taught to eat protein with each meal, which could help reduce the negative effects of carbohydrates on insulin levels.

I wonder if people who do low carb, high protein diets are more alert than those on more traditional western diets or high carb diets. That would be an interesting study.

Long-Term Use of Provent for Obstructive Sleep Apnea

CPAP is the most effective and widely used treatment for obstructive sleep apnea (OSA). Recently a new device, called Provent (see picture) has been shown to be safe and effective in the short term treatment of OSA. It works by limiting exhalation through the nose, which results in a buildup of back pressure in the upper airway. This pressure holds the upper airway open during sleep.

In the Journal of Clinical Sleep Medicine is a study of long term Provent use in OSA. Of note, it is a 12 month extension of the short-term open label study done earlier. See my earlier post from March 2011 on this short term study. Thirty-four patients were analyzed at the 12 month time point.

The median use for the entire night was 89%. The results showed significant improvements in the severity of OSA when using Provent at 12 months. The median time spent snoring while wearing Provent was reduced by 74%. The Provent group also had significant reductions in the level of daytime sleepiness. For those patients that wore Provent at the 3 month mark and had a positive response to it, there was continued benefit at the 12 month mark. The authors concluded that Provent is an effective treatment option for many OSA patients.

Provigil and Physician Alertness

Physicians in certain specialties often stay up most or all of the night when they are on call, and then have to work the entire next day. This is very taxing mentally and physically. However, it is controversial whether this acute sleep deprivation affects how physicians perform at their job. Some say it puts patients at risk for errors, while others say it has little effect on experienced physicians.

Provigil (or Modafinil) is a stimulant medication approved for shift work disorder, narcolepsy, and excessive sleepiness associated with obstructive sleep apnea. It can help workers stay alert on their overnight shift. A study was done in London on 39 male physicians where they were given either 200mg of Provigil or a placebo after one night of sleep deprivation. They were given cognitive tests and asked to use a surgery simulator program to gauge their skills.

Results showed that those doctors that used Provigil did better on the cognitive testing, including working more efficiently, planning, working memory, had less impulsivity, and were better able to redirect their attention. However, no improvements were seen in the surgical simulator program. The study authors concluded that Provigil might help sleep deprived physicians to process information better, think more flexibly, and make decisions under pressure. However, it might not improve their performance on basic procedural tasks. I wonder if because these tasks have been done so often that they could do them well whether they are rested or not.

Insomnia and Heart Attack

Insomnia is a prevalent disorder, but there has not been much data linking it to physical disorders, like cardiovascular disease. Insomnia has been associated with the development of certain psychiatric disorders, most likely being depression. There is an abstract in the journal Circulation that assessed the risk of having a heart attack (aka 'MI' for myocardial infarction) in patients that have insomnia. The study was out of Norway and included 52,610 patients that were followed for an average of 11.4 years and assessed for incidence of MI and difficulty sleeping. The researchers adjusted the data for age, gender, marital status, education, shift work, blood pressure, lipids, diabetes, body mass index, physical activity, smoking, and alcohol consumption.

The results showed that patients who reported trouble falling asleep most nights over the previous month had a 45% higher risk for MI. Patients that reported difficulty staying asleep had a 30% increase risk for MI. And waking up unrefreshed more than once a week was associated with a 27% higher risk of MI.

The researchers do not know why difficulty sleeping would contribute to higher risk of MI. I noticed that one variable they did not account for was whether the patients had obstructive sleep apnea (OSA) or other cardiac or lung diseases that could contribute to insomnia and/or raise the risk of having an MI. OSA in particular is a common cause of chronic insomnia and several studies have linked it to heart attacks. Bottom line: If you have chronic insomnia, talk to your doctor or a sleep physician...your heart might thank you.

Sleep Disturbance in Breastfed verses Formula-Fed Babies

My wife breastfed our children because we were taught it is healthier than formula feeding. I never heard that breastfeeding could permanently disrupt sleep in the baby and mother - but apparently this is common knowledge. However, research presented at the 2011 American Academy of Pediatrics National Conference and Exhibition showed that the sleep disturbance in breastfed babies is temporary.

Researchers gathered data from questionnaires and compared the sleep habits of 89 breastfed infants to 54 formula-fed infants at baseline and at follow up visits at 3, 6, 12, and 18 months later. At baseline, the breastfed infants woke up more at night and were less likely to wake up in their own bed (I guess meaning the mom brought the infant to her room to sleep). The breastfed infants also took more daytime naps than the formula-fed infants. But at the six month follow up, the only difference was that the breastfed infants were less likely to wake up in their own bed. By nine months, all differences in sleep had disappeared, and these persisted for the 12 and 18 month follow ups.

The study lead author said that the results should be reassuring to parents that want to breast feed, but have heard that it can permanently disrupt sleep more than formula feeding. Currently, the American Academy of Pediatrics recommends breastfeeding as long as possible and at least to 12 months.

Sleep Duration in Tokyo Versus Other Major Cities

I saw a report about sleep deprivation from the World Sleep Federation, which occurred in Kyoto in October 2011. The report was about a joint study between Stanford University and Ajinomoto Compnay, a Japanese foodmaker that sells a sleep supplement called Glyna. The study was a survey of 180 office workers, aged 30 to 60, from Tokyo, Paris, New York, Shanghai, and Stockholm. The Tokyo office workers averaged only 6 hours of sleep each night, with the National Sleep Foundation recommending 7 to 9 hours as ideal. Only 23% reported getting more than 7 hours of sleep each night. The workers attributed their sleep difficulties to work and personal stress, outdoor noise, the weather, and other reasons. The Tokyo workers got 36 minutes less sleep than New Yorkers and 54 minutes less than Parisians.

It could be that the Tokyo workers really do get the least amount of sleep among the 5 cities surveyed. It also could be that Japanese workers are getting more sleep than they think, and are just especially poor at judging their own sleep amounts. Or, there could be bias in this study since it was sponsored by a company that makes a product to help people sleep. If the Japanese really are getting that little sleep, could it be that their culture values sleep deprivation because it could mean they are spending more time at work? Unfortunately, sleep deprivation is unhealthy and perhaps an educational campaign might improve sleep duration in all office workers.

Restless Legs Syndrome and High Blood Pressure in Middle-Age Women

Restless legs syndrome (RLS) is a neurological disorder characterized by an urge to move the legs while resting in the evening. It gets more common with age. It can lead to insomnia and more recent studies are linking it to cardiovascular disease, as I have blogged about here and here.

Now there is a study in Hypertension: The Journal of the American Heart Association about RLS and high blood pressure (HTN) in middle aged women. Researchers conducted a cross-sectional study of 65,544 nurses aged 41-58 years old who reported RLS symptoms based on self-administered questionnaires. Women with diabetes and arthritis were excluded as these conditions can mimic RLS symptoms. Information about blood pressure values and HTN was collected via questionnaires. Adjustments were made for age, race, body mass index, physical activity, menopausal status, smoking, use of analgesics, and intake of alcohol, caffeine, folate, and iron. Compared to women without RLS symptoms, the odds were 1.2 times higher of having HTN if the women had RLS symptoms. And the more often the women had RLS symptoms, the higher the reported blood pressure values.

The results of this study are interesting, but caution is warranted. Since all of the data is from self-reported questionnaires, it can be difficult to make concrete conclusions. We don't know if the women really had RLS or one of the many mimics, since they were not examined by any physicians. Also, we don't know if the women had limb movements in sleep which could be more important for HTN than RLS by itself. Finally, we don't know if the women had sleep apnea, which would have required a sleep study. Sleep apnea is a strong risk factor for HTN and could contribute to the results seen because sleep apnea can bring on or worsen RLS. Bottom line: If you have RLS symptoms, please talk to your doctor or a sleep physician.

Oropharyngeal Examination to Predict Sleep Apnea Severity

In obstructive sleep apnea (OSA), there have been few physical exam findings that accurately correlate with the risk of having OSA. Elevated body mass index (BMI), increased neck circumference, male gender, older age, and elevated blood pressure all relate to increased risk of OSA. Other characteristics, such as the shape of the back of the mouth, have not been strongly predictive of OSA. However, in the October edition of the Archives of Otolaryngology - Head & Neck Surgery is a study about a certain way sleep physicians classify the level of crowding in the back of the mouth. It's called the Friedman tongue position (FTP), after Dr. Friedman, an ENT surgeon who does research in this area. The picture at the top left shows the FTP classification, with level 1 (upper left picture) being the least crowded and level 4 (lower right) being the most crowded. In my experience, the more crowded the back of the mouth (as in levels 3 & 4), the higher risk of having significant upper airway collapse while asleep that results in OSA.

In the study, researchers assessed 301 patients with an average age of 51 who presented to a sleep lab for suspected OSA. On physical exam, these study subjects were 71.1% were male, had a mean BMI of 29.8, and a neck circumference of 40.5 cm. Results of their sleep study showed that 94% had some degree of OSA - meaning that the population studied was relatively high risk. Subjects with FTP levels of 2 and 3 accounted for 74.1% of the whole population studied. And 14.3% had an FTP level 1, with 11.6% having an FTP level 4. In the first analysis, researchers found that the size of the tonsils, the size of the uvula, BMI, neck circumference, nasal airflow, and age were related to OSA severity. However, in the multiple regression model, only the FTP score showed a relevant relationship to OSAS severity.

The study authors concluded that since the FTP score is almost the only measurement related to OSA severity, a simple oropharyngeal examination can provide key information on this issue. And, since researchers think that almost 80% of patients with OSA have not been diagnosed, I think the FTP level could be an easy screening tool for primary care physicians to assess the potential risk of OSA and get their patients treated.