Here is an interesting article about a research study that received lots of media attention. The researchers studied the sleeping patterns of three traditional societies in Africa and South America - apparently their lifestyles resemble ancient hunter-gatherers. Results showed that the three groups slept 6 hours and 25 minutes per night on average. The sleep duration was similar between the three groups. Despite getting only 6'25" of sleep per night, the participants did not complain of feeling sleepy in the daytime and very rarely took naps.
A surprising result was that natural light did not affect the timing of sleep, as all three groups fell asleep on average 3.3 hours after sunset - which is the time when the temperature was falling. Even more interesting was that all of the group members woke up when the temperature was at its lowest.
Of note, insomnia was extremely rare - two of the groups did not even have a word for it!
Wednesday, October 28, 2015
Wednesday, October 14, 2015
Sleep and heart disease
Certain sleep disorders such as obstructive sleep apnea have been linked with cardiovascular disease. This article reviews research about sleep duration and quality and coronary artery disease. I only have access to the article and the abstract. Researchers asked subjects to rate their sleep quality and the amount of sleep they get. The results showed that those who slept 5 or less hours, or 9 or more hours, had increased rates of coronary artery calcification and stiffness - both of which are early signs of coronary artery disease.
As far as I can tell, sleep quality and duration were assessed via questionnaire. There was no sleep study or other objective sleep duration measurement such as actigraphy. So it could be that some of the subjects had poor sleep quality from un-diagnosed obstructive sleep apnea, and that could account for some of the increased rates in coronary artery disease.
As far as I can tell, sleep quality and duration were assessed via questionnaire. There was no sleep study or other objective sleep duration measurement such as actigraphy. So it could be that some of the subjects had poor sleep quality from un-diagnosed obstructive sleep apnea, and that could account for some of the increased rates in coronary artery disease.
Wednesday, September 30, 2015
CPAP use, obstructive sleep apnea, and cardiac function
Studies have shown that obstructive sleep apnea (OSA) can negatively impact cardiac function, especially if the OSA is severe. And studies have shown that treating severe OSA with CPAP can improve cardiac function. However, studies have not shown clearly that treating milder cases of OSA provides significant cardiac benefit.
This study looked at patients with mild-to-moderate OSA with mild cardiac dysfunction. Patients were minimally symptomatic with regards to OSA as well. Patients were either given CPAP for 6 months or given no CPAP. Compliance with CPAP was determined based on the CPAP download. The results did not show any convincing change in cardiac function or structure after 6 months of CPAP usage. There was no dose response effect with CPAP usage either, meaning that there still was no change in cardiac function in those that used CPAP the longest per night.
The researchers concluded that CPAP use in patients with mild OSA and mild cardiac dysfunction may not be as helpful as traditional cardiac dysfunction treatments like blood pressure medications.
This study looked at patients with mild-to-moderate OSA with mild cardiac dysfunction. Patients were minimally symptomatic with regards to OSA as well. Patients were either given CPAP for 6 months or given no CPAP. Compliance with CPAP was determined based on the CPAP download. The results did not show any convincing change in cardiac function or structure after 6 months of CPAP usage. There was no dose response effect with CPAP usage either, meaning that there still was no change in cardiac function in those that used CPAP the longest per night.
The researchers concluded that CPAP use in patients with mild OSA and mild cardiac dysfunction may not be as helpful as traditional cardiac dysfunction treatments like blood pressure medications.
Wednesday, September 23, 2015
Obstructive sleep apnea may disrupt the blood brain barrier
The blood brain barrier is like a wall that has holes in it. It allows good substances to cross from the blood vessels into the brain. At the same time, it keeps out harmful substances like bacteria and some toxins. According to this article, researchers think that some illnesses may result from the breakdown of the blood brain barrier.
The article discusses a research study showing that untreated obstructive sleep apnea (OSA) can breakdown the blood brain barrier. The researchers think that the low oxygen levels associated with OSA are responsible for the breakdown. But the breakdown may be what causes some of the symptoms of OSA, such as memory or mood problems. The researchers also think that repairing the blood brain barrier may improve these symptoms in patients with OSA. I also wonder if treating the OSA repairs the blood brain barrier - more studies will be needed to figure that out.
The article discusses a research study showing that untreated obstructive sleep apnea (OSA) can breakdown the blood brain barrier. The researchers think that the low oxygen levels associated with OSA are responsible for the breakdown. But the breakdown may be what causes some of the symptoms of OSA, such as memory or mood problems. The researchers also think that repairing the blood brain barrier may improve these symptoms in patients with OSA. I also wonder if treating the OSA repairs the blood brain barrier - more studies will be needed to figure that out.
Wednesday, September 9, 2015
Magnetic stimulation may improve nighttime bedwetting
Nighttime bedwetting, also called nocturnal enuresis, can cause family problems and embarrassment to the person suffering with it. Obviously all of us start out life as a bedwetter, but most develop nighttime control at around 5 or 6 years of age. The causes of enuresis are variable, with some cases being the result of obstructive sleep apnea (OSA). Treating the OSA improves the nocturnal enuresis.
This study evaluated the effect of magnetic stimulation on nocturnal enuresis. Researchers put the magnet over the subjects lower back, just above the tailbone. The magnet was turned off and on rapidly 5 times per week. The results showed significant reduction in nocturnal enuresis frequency. Sham magnetic stimulation also showed a reduction in nocturnal enuresis frequency that was almost as large as the real magnetic stimulation. However, the frequency of enuresis returned to baseline after the sham magnetic therapy was stopped. In the real magnetic stimulation group the effect persisted a month after therapy was stopped.
This study evaluated the effect of magnetic stimulation on nocturnal enuresis. Researchers put the magnet over the subjects lower back, just above the tailbone. The magnet was turned off and on rapidly 5 times per week. The results showed significant reduction in nocturnal enuresis frequency. Sham magnetic stimulation also showed a reduction in nocturnal enuresis frequency that was almost as large as the real magnetic stimulation. However, the frequency of enuresis returned to baseline after the sham magnetic therapy was stopped. In the real magnetic stimulation group the effect persisted a month after therapy was stopped.
Wednesday, August 26, 2015
Sleep-related breathing disorders, functional disorders, and anxiety disorders
Here is a fascinating article (at least to me) about a possible link between sleep-related breathing disorders like obstructive sleep apnea and other disorders. The other disorders are classified as "functional", meaning no etiology is agreed upon, such as fibromyalgia, chronic fatigue syndrome, and migraines. The other disorders include anxiety disorders like panic attacks and post-traumatic stress disorder (PTSD).
The researcher that is discussed in article is Dr. Gold at Stony Brook University and has published research studies on this topic. His theories about how mild OSA disorders can worsen functional and anxiety disorders is not without controversy. However, if further research confirms his theories, treatment for OSA may also help these difficult-to-treat disorders.
The researcher that is discussed in article is Dr. Gold at Stony Brook University and has published research studies on this topic. His theories about how mild OSA disorders can worsen functional and anxiety disorders is not without controversy. However, if further research confirms his theories, treatment for OSA may also help these difficult-to-treat disorders.
Wednesday, August 19, 2015
Sleep and memory
Research has shown that sleep is connected to memory. This article discusses research about that topic. I don't have access to the original research study, only the summary article provided in the link. The study setup had participants learn made-up words prior to a night of sleep or the same amount of time awake. The participants were then asked to recall the words after a period of sleep or wakefulness.
The results showed that when compared to wakefulness, sleep helped the participants recall forgotten words. One of the researchers concluded that "sleep almost doubles our chances of remembering previously unrecalled material. The post-sleep boost in memory accessibility may indicate that some memories are sharpened overnight. This supports the notion that, while asleep, we actively rehearse information flagged as important."
The results showed that when compared to wakefulness, sleep helped the participants recall forgotten words. One of the researchers concluded that "sleep almost doubles our chances of remembering previously unrecalled material. The post-sleep boost in memory accessibility may indicate that some memories are sharpened overnight. This supports the notion that, while asleep, we actively rehearse information flagged as important."
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