Withdrawal of CPAP for two days in patients with obstructive sleep apnea

In patients with obstructive sleep apnea (OSA), no matter the severity, I tell them to use their CPAP every time they sleep. This provides the best results of their therapy. Of course, not everyone can or will use it EVERY night. I explain that the CPAP is not curing their OSA. However, using CPAP nightly for weeks or months on end can mildly reduce the severity, especially if they already have severe OSA. Here is a study demonstrating just that effect. They studied patients initially in the lab to make the diagnosis. Then they used the CPAP continuously for 4 months on average. Then they went two nights without the CPAP and had repeat sleep studies. The results showed that for those with mild to moderate OSA, there was no difference in OSA severity, objective sleepiness, subjective sleepiness, or sleep architecture when off the CPAP. However, in the ones with severe OSA, there was a mild improvement in OSA severity - but they still had severe OSA! But subjective and objective sleepiness levels were no different. The authors think (and I agree) that treating severe OSA for a few months may reduce inflammation in the upper airway enough to mildly reduce the OSA severity. But, because they still have severe OSA, they continue to feel sleepy when not using their CPAP. So use your CPAP every time you sleep if you want to feel as good as you can.

Mattress buying tips and myths

I don't know much about mattresses. But someone told me that buying a mattress is like buying shoes. You get what you pay for. You may sleep better on a more expensive mattress, just like your feet may be more comfortable in more expensive shoes. And since you spend about one-third of your life on a mattress, better make it a good and comfortable one. This article discusses how to buy a mattress. One interesting thing is that the author says mattresses double in weight every 10 years from dust mites - living and dead ones. That's enough to give someone insomnia!

Yoga may improve restless legs syndrome

This article demonstrates in a small group of women with restless legs syndrome (RLS) improved with regular yoga. There is no control group, so it's not clear that the yoga itself improved their RLS. In many patients, RLS symptoms wax and wane, so some of the improvement may be regression toward the mean - the RLS may have gotten better with time alone, and the yoga may not have anything to do with it. Also, exercise has been shown to help RLS - not just yoga.

Exercising close to bedtime may not disturb sleep

This article discusses results of a National Sleep Foundation poll showing that exercise close to bedtime does not interfere with sleep. The article discusses that it is not true that exercise close to bedtime will disrupt sleep. I completely agree. I used to be a long distance runner. In high school and high school, I would run late at night after work. I slept like a baby. But the article misses the important point about exercise and insomnia. For those with chronic insomnia, exercise close to bedtime can worsen insomnia.

This article could be about anything you hear about sleep - don't drink caffeine before bedtime, watch TV in bed, sleep in on the weekends, take naps. All of these are fine to do...IF you don't have insomnia. If you do have insomnia, than the above activities can worsen the insomnia. So in you "good" sleepers, go ahead and workout close to bedtime. For you chronic insomniacs, you also need to exercise, but do it in the morning, or no later than late afternoon.

Swine Flu Vaccine and Narcolepsy

Narcolepsy is a sleep disorder that causes excess sleepiness. It's not a common disorder, and can be hard to diagnose. There have been several news reports about the link between a flu vaccine given in Europe and narcolepsy. This report shows that there may be a link between the two. Researchers think that the immune system may be involved in development of narcolepsy, and that the vaccine tricks the immune system in predisposed individuals. However, correlation does not equal causation. More, larger studies are needed to show that narcolepsy may have been caused by this vaccine.

Obstructive sleep apnea, stroke, and atrial fibrillation

Obstructive sleep apnea (OSA), stroke, and atrial fibrillation are related. OSA can increase risk of stroke. So can atrial fibrillation. OSA can make it harder for cardiologists to control atrial fibrillation. Here is a study that studied these three conditions. They monitored people with OSA to see if they had a stroke. In those that did have a stroke, atrial fibrillation was much more common. This suggests a relationship between atrial fibrillation and OSA in stroke development. And this relationship was true after adjusting for common conditions like age, diabetes, body mass index, etc.

Sleep loss can affect gene expression

This article got some press, so I thought I would comment on it. Researchers took 26 healthy people, and allowed them six or less hours of sleep per night for a week. They then kept them up for 40 hours straight and then let them sleep as much as they want, up to 10 hours per night for another week. I can only see the abstract, so some of the details are unknown. From blood samples, researchers determined that 711 different genes were altered during the sleep deprivation period. The blood samples were taken 3 hours apart as the participants stayed up for 40 hours straight. It's not clear why they did this - it could alter the results. The genes that were affected play a part in metabolism and our internal body clock. However, some of the genes affected have no known function. From the abstract, it's not clear that the genes were altered by the week of deprivation or the 40 hour total sleep loss.

Chemicals involved in the sleep of seals

Apparently, seals are able to sleep in the water. But only half their brain sleeps at a time in the water. On land, their whole brain sleeps. This article discusses research findings involving two chemicals in the brain involved in seal sleep. Acetylcholine is high in the side of the brain still awake whereas serotonin is equal on both sides. Unfortunately, sleep in humans is still more complex than just these two neurochemicals. Other important ones are orexins, histamine, norepinephrine, and dopamine. But this research may allow sleep scientists to help figure out how the neurochemicals are related and involved in sleep, so that one day we may be able to better understand and treat sleep disorders.

Simple changes in the ICU can reduce delirium

This article discusses research showing that better sleep can reduce delirium in ICU patients. Many patients in an intensive care unit get delirious - a brain disorder that leaves the patient confused, sleepy, inattentive. It can be dangerous and hard to treat. Getting too little sleep can exacerbate delirium. ICU's are not known for their good sleep environment with constant interruptions by staff to assess these really sick patients. This research showed that simple environmental changes were able to reduce delirium by 54%. The interventions included turning off televisions, turning off room and hallway lights, limiting the number of staff visits to patient rooms overnight for drawing blood and giving medications to reduce interruptions, reducing overhead pages and minimizing unnecessary equipment alarms. The patients also were offered eye masks, ear plugs, and tranquil music. In the final stage, a new medication guideline was introduced that discouraged giving patients certain commonly prescribed drugs for sleep, such as benzodiazepines, that are known to cause delirium.

One night of complete sleep loss can affect eating behavior

Here is another study about eating and sleep. Researchers continue to try to blame sleep loss on the obesity epidemic, and I continue to be skeptical. Sleep loss may be a small factor, but eating habits and lack of exercise are much bigger contributors. In this study, researchers took healthy young men and monitored their eating habits after a normal night of sleep and then after staying up entirely for a single night. The results showed that the men who were sleep deprived tended to eat greater proportions of energy dense snacks. Their meal portions were the same. The authors conclude that total sleep deprivation can increase food intake, especially energy dense food. This may be true, but it's a long stretch to say this is responsible for obesity. These were non-obese men with only one night of sleep deprivation. We need larger studies in people who are chronically, but partially sleep deprived. This study of only one night of total sleep deprivation does not add much to the discussion of sleep deprivation and obesity.

Should you get enough sleep? Of course. Is more sleep going to help you lose weight? Only if you change what you eat and exercise.

Periodic limb movements in sleep, heart abnormalities, and hemodialysis

Periodic limb movements in sleep (PLMS) are repetitive, small leg jerks that occur during sleep, usually without any memory of it happening. However, PLMS can fragment sleep and have been linked to increased cardiovascular risk factors. Restless legs syndrome (RLS) is linked to PLMS - most RLS patients have PLMS. RLS and PLMS are common in hemodialysis patients. And hemodialysis itself is linked to cardiovascular disease. This study sought to determine if patients with RLS and PLMS on hemodialysis had a deterioration in heart structure and function compared to those RLS patients without PLMS.

Researchers used a cutoff value for the PLMS that puts them in the moderate to severe amount - this is most likely to be clinically significant. Results showed that resting heart rate and blood pressure (BP) were similar in those with and without PLMS. The minimum systolic BP (referring to the 120 in "120 over 80" for example) was higher in the PLMS group. Also, the percent reduction of BP during sleep, compared to being awake, was 50% smaller in the PLMS group. This means that those with PLMS did not experience as much a dip in BP during sleep - something that could lead to high blood pressure in the daytime. The mass of the left side of the heart was greater in PLMS group, but both groups had hearts that could pump out the same amount of blood per beat.

The authors concluded that PLMS can alter the structure of the heart, but not necessarily its function. They feel that PLMS do this by raising blood pressure during sleep. The heart gets larger when it has to pump against a higher blood pressure, which can lead to the results obtained in this study. Of note, the RLS itself was not associated with the heart structure changes.

What does this mean? It means that patients with RLS on hemodialysis may need to be studied for PLMS. More studies will be needed though to find out if treating PLMS improves results.

Oral appliances for obstructive sleep apnea lower blood pressure

Oral appliances are a type of mouth guard worn at night when asleep to treat obstructive sleep apnea (OSA). I use them in patients with mild to moderate OSA, and in those with severe OSA but who don't respond to CPAP. OSA is strongly associated with high blood pressure (HTN), and CPAP has been shown to help reduce HTN by treating OSA. There have not been many studies showing that oral appliances reduce blood pressure when used to treat OSA. This paper pooled data from 7 studies that measured blood pressure changes in OSA patients using an oral appliance. The results showed that in those with mild to moderate OSA, an oral appliance modestly improved blood pressure, and results were comparable to CPAP.

Nightmares and beliefs about sleep are related to suicidal thoughts

This article in the Journal of Clinical Sleep Medicine discusses the relationship between nightmares, beliefs about sleep and insomnia, and suicidal thoughts. Apparently, studies have shown that insomnia symptoms are related to near lethal suicide attempts. Nightmares are also linked to suicidal thoughts and completions.

This study gave questionnaires to patients that presented with suicidal thoughts or attempts. Insomnia symptoms were common in these patients. Nightmares were also present. These symptoms remained significant even after adjusting for the effects of depression - which can increase risk of suicide and insomnia. The researchers analyzed these patients thoughts and beliefs about sleep and insomnia - such as, "if I don't sleep well, I will not be able to function at all the next day."

The findings suggest that the insomnia symptoms themselves were not the determining factor for suicidal thoughts - it was the thoughts about the consequences and causes of insomnia that was related to suicidal thoughts. Nightmares also increased the risk of being suicidal. This makes sense. Many people wouldn't mind insomnia as much if they felt it didn't impact their daytime functioning or possibly affect their health. The researchers noted a sense of hopelessness about insomnia - meaning these insomniacs did not think they ever would sleep better. And therefore, their daytime functioning and how they felt in the daytime would never improve. It reminds me of patients that deal with chronic, unrelenting pain - they can become hopeless about ever living a life without pain.

Unlike chronic pain, however, insomnia can get better with behavioral therapy. Recognizing this is important for physicians and mental health workers, so that they can refer their at risk patients with insomnia for appropriate treatment.