Depression is a common disorder that exists along with obstructive sleep apnea (OSA). The exact relationship between the two disorders is not known. OSA may contribute to depression due to sleep loss, sleep disruption, and cognitive effects of intermittent low oxygen levels to the brain. Also, weight gain and sleep disruption from depression could exacerbate OSA. Some, but not all of my patients report that their depression gets better with treatment of OSA.
This study is a meta-analysis of research looking at the effects of CPAP and oral appliances on depressive symptoms (as obtained by depression questionnaires) in adults with OSA. The results showed small improvements in depressive symptoms with OSA treatment. The greatest benefit was seen in those patients with the worse depression scores at baseline.
Wednesday, December 24, 2014
Wednesday, December 17, 2014
Insomnia and mortality
Chronic insomnia is a frequent problem, and several studies have attempted to link insomnia with medical problems, even death. However, it's not clear from these studies that the relationship is as stated. One methodology problem with these studies is the fact that most of them define insomnia based solely on the research subjects' description of their sleep quality. In other words, secondary causes of insomnia are not ruled out with objective testing like sleep studies. This abstract is about research done on subjects with chronic insomnia. I don't have access to the actual article, so my analysis of the study is limited. I can't tell from the abstract if the research subjects had secondary causes of insomnia ruled out with sleep studies.
Researchers used data from a community-based cohort and categorized subjects into having either persistent, chronic insomnia, only intermittent insomnia, or no insomnia. The researchers defined persistent based on the subjects' description of their sleep quality over a six year period. They then determined when the subject died for up to a 20 year period. The researchers also examined levels of a marker of inflammation called serum C-reactive protein (CRP). There were 1409 research subjects - 249 with intermittent insomnia and 128 with persistent insomnia. The results showed that the subjects with persistent insomnia were 58% more likely to die than those without insomnia. Those with intermittent insomnia were not more likely to die than those without insomnia. Of note, most of the deaths were cardiovascular. CRP levels were higher in those with persistent insomnia than in those with either intermittent or no insomnia. The authors noted that CRP levels were associated with increased mortality by themselves. However, adjustment for CRP levels did not notably change the association between persistent insomnia and mortality. Also, the results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives.
Researchers used data from a community-based cohort and categorized subjects into having either persistent, chronic insomnia, only intermittent insomnia, or no insomnia. The researchers defined persistent based on the subjects' description of their sleep quality over a six year period. They then determined when the subject died for up to a 20 year period. The researchers also examined levels of a marker of inflammation called serum C-reactive protein (CRP). There were 1409 research subjects - 249 with intermittent insomnia and 128 with persistent insomnia. The results showed that the subjects with persistent insomnia were 58% more likely to die than those without insomnia. Those with intermittent insomnia were not more likely to die than those without insomnia. Of note, most of the deaths were cardiovascular. CRP levels were higher in those with persistent insomnia than in those with either intermittent or no insomnia. The authors noted that CRP levels were associated with increased mortality by themselves. However, adjustment for CRP levels did not notably change the association between persistent insomnia and mortality. Also, the results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives.
Wednesday, December 10, 2014
Obstructive sleep apnea and exercise capacity
This study is a cross-sectional evaluation of the relationship between obstructive sleep apnea (OSA) and exercise capacity. According to the authors, how OSA affects exercise capacity is not clear, as prior studies have conflicting results. In this study, researchers did sleep studies on participants and put them into two groups. Those with no or mild OSA, and those with moderate or severe OSA. They then measured their exercise capacity and compared the results. The main finding was that OSA was associated with decreased exercise capacity. And more severe OSA was associated with worsening exercise capacity. The mechanism behind why OSA would affect exercise capacity is not clear. The authors speculate that it could be due to changes in energy pathways, changes in muscle fiber structure, and/or changes in blood vessels in muscles - thought to be a result of low oxygen levels associated with OSA.
Wednesday, December 3, 2014
Smoking and sleep
This article describes research about reducing cigarette smoking in your sleep. The study in the article involves using a psychological concept of learning called respondent conditioning - think of Pavlov and his dog, at outlined in this Wikipedia article. The study participants were all smokers who expressed desire to quit. Researchers paired the smell of cigarettes with a foul odor when participants were asleep. Supposedly, the participants unconsciously associated the foul smell with the smell of cigarettes and ended up smoking 30% less. There was no smoking reduction in participants that were exposed only to cigarette smoke when asleep or if the participants were exposed to both smells, but while awake.
Two other interesting points about this study. The first one is that the participants did not remember the smells they were exposed to in their sleep. Also, it appeared that a light stage of non-dream sleep was was the most effective stage of sleep that was associated with reduced smoking. The authors concluded that conditioning can occur in sleep and that this technique may be used in other addictions.
Two other interesting points about this study. The first one is that the participants did not remember the smells they were exposed to in their sleep. Also, it appeared that a light stage of non-dream sleep was was the most effective stage of sleep that was associated with reduced smoking. The authors concluded that conditioning can occur in sleep and that this technique may be used in other addictions.
Wednesday, November 26, 2014
Adenotonsillectomy and asthma in children
Some research studies have demonstrated an association between obstructive sleep apnea (OSA) and asthma. It's not clear why they are linked - it could be that both involve inflammation. OSA is also associated with obesity, which is linked to asthma. The most common treatment for OSA in children is the surgical removal of adenoids and tonsils, referred to as an adenotonsillectomy (AT). This study looked at historical medical and pharmacy records of children with asthma who did and did not have AT. The data in this study was from quite a large database, and the children who had AT were matched with those without AT.
The results showed that asthma flare-ups were worse in children the year prior to AT. However, after AT, asthma flare-ups declined significantly, to levels similar to the kids with asthma who did not receive AT. A similar decrease was seen in asthma medication refills in those children who underwent AT.
The study authors conclude that the presence of OSA can worsen asthma control in children, and that treatment of the OSA with AT may reduce asthma flare-ups. The authors appropriately caution that prospective studies will be needed to establish a causal relationship.
The results showed that asthma flare-ups were worse in children the year prior to AT. However, after AT, asthma flare-ups declined significantly, to levels similar to the kids with asthma who did not receive AT. A similar decrease was seen in asthma medication refills in those children who underwent AT.
The study authors conclude that the presence of OSA can worsen asthma control in children, and that treatment of the OSA with AT may reduce asthma flare-ups. The authors appropriately caution that prospective studies will be needed to establish a causal relationship.
Wednesday, November 19, 2014
Sleep apnea and sex
Studies have shown that obstructive sleep apnea (OSA) increases risk of erectile dysfunction (ED), and treating OSA with CPAP can improve ED. And some of my patients with untreated OSA are just too tired to engage in sex. Finally, some of my patients are hesitant to start CPAP therapy because they worry it will interfere with their sex life. This is usually in my younger patients and some of it is a misunderstanding about when CPAP is worn. Some think it's supposed to be worn whenever they are in their bed, as opposed to just sleeping.
This article discusses research presented at a recent meeting. Researchers asked participants about their sexual quality of life. The participants all has OSA and were prescribed CPAP therapy. The researchers divided the participants into two groups - those that used the CPAP regularly and those that did not. Results showed no difference in sexual quality of life between the two groups. The conclusion was that CPAP did not interfere with the participants sexual satisfaction.
This article discusses research presented at a recent meeting. Researchers asked participants about their sexual quality of life. The participants all has OSA and were prescribed CPAP therapy. The researchers divided the participants into two groups - those that used the CPAP regularly and those that did not. Results showed no difference in sexual quality of life between the two groups. The conclusion was that CPAP did not interfere with the participants sexual satisfaction.
Wednesday, November 12, 2014
Postoperative outcomes in obstructive sleep apnea
Patients with undiagnosed obstructive sleep apnea (OSA) are thought to be at higher risk after an operation than those who have already been diagnosed and are being treated with CPAP therapy. Current practice guidelines recommend screening for obstructive sleep apnea before an operation, and starting CPAP therapy prior to surgery if feasible. Routine monitoring of patients with OSA is recommended after many types of surgery.
This study looked at historical outcomes after surgery that occurred before the implementation of the current practice guidelines. The study included data on adults and compared them to controls at low risk of having sleep apnea. The control patients were matched for the type of surgery, indication for the surgery, and date of the surgery.
The results showed that the risk of cardiovascular complications, primarily cardiac arrest and shock, was increased in undiagnosed obstructive sleep apnea but not diagnosed obstructive sleep apnea. However the risk of respiratory complications, primarily Acute Respiratory Distress Syndrome (ARDS) and acute respiratory failure was increased in both groups without significant difference in risk between them. Also, the results showed that increasing severity of obstructive sleep apnea, age, comorbid disease, and the type of surgery were also important risk predictors for postoperative complications.
The study was not designed to determine whether reduction in cardiovascular complications in those patients diagnosed with OSA was due to CPAP use as usage of CPAP was not measured immediately after surgery.
This study looked at historical outcomes after surgery that occurred before the implementation of the current practice guidelines. The study included data on adults and compared them to controls at low risk of having sleep apnea. The control patients were matched for the type of surgery, indication for the surgery, and date of the surgery.
The results showed that the risk of cardiovascular complications, primarily cardiac arrest and shock, was increased in undiagnosed obstructive sleep apnea but not diagnosed obstructive sleep apnea. However the risk of respiratory complications, primarily Acute Respiratory Distress Syndrome (ARDS) and acute respiratory failure was increased in both groups without significant difference in risk between them. Also, the results showed that increasing severity of obstructive sleep apnea, age, comorbid disease, and the type of surgery were also important risk predictors for postoperative complications.
The study was not designed to determine whether reduction in cardiovascular complications in those patients diagnosed with OSA was due to CPAP use as usage of CPAP was not measured immediately after surgery.
Wednesday, November 5, 2014
Energy drinks and athletes
Energy drinks like Red Bull and Monster are all the rage right now. Apparently, athletes are using them to enhance performance. This study assessed responses to energy drinks compared to placebo in athletes. The results showed athletes increased their "sporting performance by between 3% and 7%." Athletes were also able to up their performance at high intensities. The results also showed that "Energy drinks increase jump height for basketball players, muscle force and power for climbers and trained individuals, swimming speed for sprinter swimmers, hit force and accuracy for volleyball players, and the number of points scored in tennis.”
However, the energy drinks increased the frequency of insomnia, nervousness, and the level of stimulation in the hours following the competition. The researchers attributed all of the positive and negative effects to the caffeine in these energy drinks. The other ingredients did not seem to produce any benefit above the caffeine.
However, the energy drinks increased the frequency of insomnia, nervousness, and the level of stimulation in the hours following the competition. The researchers attributed all of the positive and negative effects to the caffeine in these energy drinks. The other ingredients did not seem to produce any benefit above the caffeine.
Wednesday, October 29, 2014
Tongue fat and sleep apnea
Apparently your tongue is fat. I mean that there is a normal amount of fat within your tongue muscle. And if you have obstructive sleep apnea (OSA), you may have too much tongue fat. At least according to this recent study. Researchers used sophisticated MRI scans to compare the overall volume and amount of fat in the tongues of overweight men with and without OSA. The results showed that the more obese the subject, the larger the tongue and the higher amount of fat in the tongue. There was also a significant association between belly fat and tongue fat. Patients with OSA had more tongue fat than in the control patients. They also had higher tongue volumes and a higher percentage of tongue fat. There was also an association between the sleep apnea severity and the tongue volume as well as amount of tongue fat.
The amount of fat was greatest in the back of the tongue rather than the front of the tongue in the patients with OSA. This makes sense anatomically because the back of the tongue is involved in blocking off the upper airway during sleep apnea. Another interesting finding was that the researchers examined the chewing muscle and it did not have a higher percentage of fat. This means that when patient's have extra weight, it's not deposited uniformly in the neck and head, but only in certain areas.
Finally, the researchers suggest that the increased amount of fat in the tongue in those with OSA can inhibit the way the tongue normally moves out of the way to allow air to flow.
The amount of fat was greatest in the back of the tongue rather than the front of the tongue in the patients with OSA. This makes sense anatomically because the back of the tongue is involved in blocking off the upper airway during sleep apnea. Another interesting finding was that the researchers examined the chewing muscle and it did not have a higher percentage of fat. This means that when patient's have extra weight, it's not deposited uniformly in the neck and head, but only in certain areas.
Finally, the researchers suggest that the increased amount of fat in the tongue in those with OSA can inhibit the way the tongue normally moves out of the way to allow air to flow.
Wednesday, October 22, 2014
Salt water infusion and sleep apnea
Sleep researchers have not worked out exactly how we develop obstructive sleep apnea (OSA). There are several risk factors and anatomical reasons involved. Some researchers have postulated that OSA may be worsened by fluid shifting from the legs to the neck area overnight. In other words, because the legs are generally at the level of the heart while in bed, fluid from the legs moves into the neck area, causing swelling in the upper airway. This narrows the upper airway enough to restrict airflow.
In this article in the Journal Sleep, researchers studied older and younger men to see if giving them IV salt water impacted the level of sleep apnea. The study was limited to men who were not obese and had either no or non-severe OSA. They did sleep studies after giving them the IV salt water. The results showed that the IV salt water worsened OSA significantly in older men, but not younger men. The reason for this was not clear from the study. However, the results have important implications for older men undergoing surgery, since IV fluids are commonly given during and right after surgery.
In this article in the Journal Sleep, researchers studied older and younger men to see if giving them IV salt water impacted the level of sleep apnea. The study was limited to men who were not obese and had either no or non-severe OSA. They did sleep studies after giving them the IV salt water. The results showed that the IV salt water worsened OSA significantly in older men, but not younger men. The reason for this was not clear from the study. However, the results have important implications for older men undergoing surgery, since IV fluids are commonly given during and right after surgery.
Wednesday, October 15, 2014
Hibernation to reduce the cost of manned space flights
Here is a fascinating article about space travel. Apparently, a trip to Mars will take about 6 months. A team at NASA has shown that putting astronauts in a form of hibernation can significantly reduce the cost of a trip, as much less food will need to be brought if the crew is hibernating.
The way it works is that the crew members will be cooled down to 89°F – 93°F by fluid pumped through their noses! The crew will be fed intravenously while they hibernate. The article does not mention how urination is dealt with - catheter maybe? When the crew arrives at Mars, they will be warmed up again and woken up. The article mentions that during hibernation, the crew will be in a "spinning habitat...to offset bone and muscle loss." Sounds like something out of a science fiction movie, only apparently it's very possible to do this now.
The way it works is that the crew members will be cooled down to 89°F – 93°F by fluid pumped through their noses! The crew will be fed intravenously while they hibernate. The article does not mention how urination is dealt with - catheter maybe? When the crew arrives at Mars, they will be warmed up again and woken up. The article mentions that during hibernation, the crew will be in a "spinning habitat...to offset bone and muscle loss." Sounds like something out of a science fiction movie, only apparently it's very possible to do this now.
Wednesday, October 8, 2014
Rising prevalence of obstructive sleep apnea
Obstructive sleep apnea (OSA) is becoming more common in the U.S. When I was a sleep disorders fellow, it was thought that OSA occurred in 2% of women and 4% of men. This article highlights how the rates of OSA have increased in the past two decades. Apparently, OSA now is present in at least 25 million adults in the U.S. and in 26% of adults between the ages of 30 and 70 years old.
The article discusses the complications of untreated OSA too. It does not discuss why the prevalence rates have risen. I suspect more public awareness of the symptoms, more acceptable treatment options, rising obesity rates, and aging population contribute to the increase in OSA rates.
The article discusses the complications of untreated OSA too. It does not discuss why the prevalence rates have risen. I suspect more public awareness of the symptoms, more acceptable treatment options, rising obesity rates, and aging population contribute to the increase in OSA rates.
Wednesday, October 1, 2014
Deep sleep circuit in the brain
There are 4 different sleep stages that humans cycle through at night. Deep sleep is one of those stages, and is typically seen in the first half of the night, at least in adults. Sleep researchers do not know exactly how deep sleep is produced, but it's thought to involve the neurotransmitter GABA, which stands for gamma-aminobutyric acid.
Here is a report of a study involving stimulation of a deep part of the brain (the brainstem) that turns on deep sleep. The technique used to stimulate this area of the brain is different than other methods involving electrical stimulation of the cells in the brainstem felt to be responsible for deep sleep. With electrical stimulation, the problem is that the electrode stimulates everything it touches, including surrounding areas it did not come into contact with. As stated in the article, electrically stimulating cells was like using a sledgehammer, when what was needed was a scalpel. In this study, researchers inserted a harmless virus that incorporated itself precisely into the very cells the researchers were trying to study. The cells were then remotely "turned on" and the animals went right into deep sleep.
This is exciting research as it points to the possibility of developing therapies that enhance deep sleep by targeting only certain brain areas. Hopefully this will lead to treatments with more specific modes of action and less side effects.
Here is a report of a study involving stimulation of a deep part of the brain (the brainstem) that turns on deep sleep. The technique used to stimulate this area of the brain is different than other methods involving electrical stimulation of the cells in the brainstem felt to be responsible for deep sleep. With electrical stimulation, the problem is that the electrode stimulates everything it touches, including surrounding areas it did not come into contact with. As stated in the article, electrically stimulating cells was like using a sledgehammer, when what was needed was a scalpel. In this study, researchers inserted a harmless virus that incorporated itself precisely into the very cells the researchers were trying to study. The cells were then remotely "turned on" and the animals went right into deep sleep.
This is exciting research as it points to the possibility of developing therapies that enhance deep sleep by targeting only certain brain areas. Hopefully this will lead to treatments with more specific modes of action and less side effects.
Wednesday, September 24, 2014
Insomnia and obstructive sleep apnea
I've followed Dr. Barry Krakow's work for years, starting when I was a fellow at Dartmouth. Dr. Krakow is an expert on insomnia, nightmare treatments, and obstructive sleep apnea (OSA). I have a copy of one of his insomnia books, called Sound Sleep, Sound Mind, and I recommend it highly. Besides treating nightmares, Dr. Krakow has brought to the mainstream the common co-existence of insomnia and OSA, and the relationship to each other. Now, he has published an exciting paper in the Mayo Clinic Proceedings, but I don't have access to it - all I have is the abstract.
In this study, Dr. Krakow evaluated over 1200 patients with chronic insomnia. Almost three-fourths of the insomnia patients did not respond to medications for their insomnia. Dr. Krakow studied 942 of them in the sleep lab using the most modern testing equipment, not done in older insomnia studies. Results showed that over 90% of these patients had moderate to severe OSA! The results are somewhat surprising with respect to the percentage of insomnia patients that had undiagnosed OSA. In my clinic, I regularly get patients referred to me for "insomnia" that actually have OSA, and sometimes it is severe. In these cases, treating the OSA usually improves sleep quality significantly such that sleeping pills are no longer needed.
The bottom line is that patients with chronic insomnia that do not respond to medications may benefit from referral to a sleep specialist for evaluation of underlying medical causes of the insomnia, such as OSA.
In this study, Dr. Krakow evaluated over 1200 patients with chronic insomnia. Almost three-fourths of the insomnia patients did not respond to medications for their insomnia. Dr. Krakow studied 942 of them in the sleep lab using the most modern testing equipment, not done in older insomnia studies. Results showed that over 90% of these patients had moderate to severe OSA! The results are somewhat surprising with respect to the percentage of insomnia patients that had undiagnosed OSA. In my clinic, I regularly get patients referred to me for "insomnia" that actually have OSA, and sometimes it is severe. In these cases, treating the OSA usually improves sleep quality significantly such that sleeping pills are no longer needed.
The bottom line is that patients with chronic insomnia that do not respond to medications may benefit from referral to a sleep specialist for evaluation of underlying medical causes of the insomnia, such as OSA.
Wednesday, September 17, 2014
Brain changes before and after CPAP treatment for obstructive sleep apnea
Some studies have shown changes in the white and gray matter of the brain from untreated obstructive sleep apnea (OSA). The gray matter refers to cell bodies in the brain and is generally on the outer surface. White matter is the connections between the cell bodies and some of the supporting cell types - it's deeper in the brain, meaning below the gray matter.
This study sought to evaluate white matter changes and impact on cognition in patients with OSA, and if the changes were reversible with CPAP therapy. The researchers studied 17 patients with severe OSA and compared them to similar patients that did not have OSA. The treated patients were evaluated at baseline, 3 months, and at 12 months - however, the controls were only evaluated at baseline. CPAP use was monitored objectively with downloads from each unit.
Results showed changes in white matter in the untreated OSA patients. There was only limited improvement with 3 months of CPAP, but there was significant improvement at 12 months of CPAP. This is an exciting study because it suggests that the brain damage inflicted by untreated severe OSA may be reversible with regular, prolonged CPAP treatment.
This study sought to evaluate white matter changes and impact on cognition in patients with OSA, and if the changes were reversible with CPAP therapy. The researchers studied 17 patients with severe OSA and compared them to similar patients that did not have OSA. The treated patients were evaluated at baseline, 3 months, and at 12 months - however, the controls were only evaluated at baseline. CPAP use was monitored objectively with downloads from each unit.
Results showed changes in white matter in the untreated OSA patients. There was only limited improvement with 3 months of CPAP, but there was significant improvement at 12 months of CPAP. This is an exciting study because it suggests that the brain damage inflicted by untreated severe OSA may be reversible with regular, prolonged CPAP treatment.
Wednesday, September 10, 2014
Benefit of CPAP use in older people with obstructive sleep apnea
Here is a study about obstructive sleep apnea (OSA) treatment in elderly people. It was done in the UK over 12 months in those 65 years and older with OSA. Subjects were randomized to get CPAP treatment or no CPAP treatment. Those who did not get CPAP received advice on minimizing daytime sleepiness through sleep habits, napping, caffeine use, and weight loss. The main purpose of the study was to see if CPAP use reduced sleepiness levels and if CPAP is cost-effective.
Results showed that subjective sleepiness was reduced to a greater extent in those that received CPAP treatment. As expected, the reduction in sleepiness levels was greatest for those who started out with the highest sleepiness levels. CPAP use reduced healthcare usage, which offset the cost of the CPAP - the authors concluded that CPAP use is cost effective for older patients.
Other outcomes were measured as well. CPAP use did not improve cognitive function or blood pressure. CPAP did improve total cholesterol levels at 3 months, but not at 21 months. Night time urination, and home and driving accidents were not improved with CPAP use.
What is most interesting to me about this study is that CPAP improved sleepiness despite a low amount of CPAP use by the participants. Good CPAP usage is generally defined as using CPAP at least 4 hours per night on 7 out of 10 nights. In this study, usage was about 2 hours per night on average.
Results showed that subjective sleepiness was reduced to a greater extent in those that received CPAP treatment. As expected, the reduction in sleepiness levels was greatest for those who started out with the highest sleepiness levels. CPAP use reduced healthcare usage, which offset the cost of the CPAP - the authors concluded that CPAP use is cost effective for older patients.
Other outcomes were measured as well. CPAP use did not improve cognitive function or blood pressure. CPAP did improve total cholesterol levels at 3 months, but not at 21 months. Night time urination, and home and driving accidents were not improved with CPAP use.
What is most interesting to me about this study is that CPAP improved sleepiness despite a low amount of CPAP use by the participants. Good CPAP usage is generally defined as using CPAP at least 4 hours per night on 7 out of 10 nights. In this study, usage was about 2 hours per night on average.
Wednesday, September 3, 2014
American Pediatric Association "Let Them Sleep" statement
The American Pediatric Association recently released a statement that middle and high school students start school at 8:30 AM or later. Sleep-related research supports the later school start time so that adolescents can get more sleep per night. The recommended amount of sleep for teenagers is 8.5 to 9 hours per night, with the majority of teens not getting close to that. Chronic sleep deprivation has been linked with obesity, diabetes, mental health problems, and reduced academic performance.
The statement goes on to explain that teens lack of sleep is complex and involves homework, extracurricular activities, after-school jobs and use of technology that can keep them up late on week nights. So just delaying school start times may not improve teens' sleep duration if other lifestyle changes are not made. The most obvious one is restricting screen time at night.
The statement goes on to explain that teens lack of sleep is complex and involves homework, extracurricular activities, after-school jobs and use of technology that can keep them up late on week nights. So just delaying school start times may not improve teens' sleep duration if other lifestyle changes are not made. The most obvious one is restricting screen time at night.
Wednesday, August 27, 2014
Astronauts and sleep
This article discusses a study published in the journal Lancet about the sleep patterns of astronauts in space. Since I don't have access to the Lancet article, I don't have all of the details. The article however states that the astronauts are scheduled to get 8.5 hours per day of sleep. On average, they managed to sleep about 6 hours. And 78% of them used sleeping pills about half of the time.
The article goes on to quote someone from NASA who states that the study demonstrates valuable insights into sleep deprivation experienced by astronauts in space. However, I'm not sure it does, but I am basing this on the article, not the actual study. The article doesn't give me any insight, only leads to more questions. Why are astronauts expected to sleep 8.5 hours per night? Who came up with that number? How was sleep measured in the astronauts? Subjective or objective information? For the astronauts that did not sleep the full 8.5 hours, were they sleepy in the daytime? Did they actually exhibit any signs of sleep deprivation? Why did the astronauts take sleep aids? Was it because they were told they needed to sleep 8.5 hours, but most realized they would not be able to do that because the amount of sleep they actually need is less?
The article goes on to quote someone from NASA who states that the study demonstrates valuable insights into sleep deprivation experienced by astronauts in space. However, I'm not sure it does, but I am basing this on the article, not the actual study. The article doesn't give me any insight, only leads to more questions. Why are astronauts expected to sleep 8.5 hours per night? Who came up with that number? How was sleep measured in the astronauts? Subjective or objective information? For the astronauts that did not sleep the full 8.5 hours, were they sleepy in the daytime? Did they actually exhibit any signs of sleep deprivation? Why did the astronauts take sleep aids? Was it because they were told they needed to sleep 8.5 hours, but most realized they would not be able to do that because the amount of sleep they actually need is less?
Wednesday, August 20, 2014
Drowsy driving
Driving while drowsy continues to be a significant problem. It affects drivers of all age. I'm just referring to drivers who fall asleep at the wheel - also drivers who are sleep deprived enough to impair their reaction times on the road. This level of impairment can be difficult for a driver to recognize. Therefore a sleepy driver may push on, continuing to drive because they have not actually fallen asleep.
Here is a link to recent statistics from the National Highway Traffic Safety Association citing that approximately one in four motor vehicle accidents is due to drowsy driving. Someday, sleep researchers may come up with a reliable and simple test of sleepiness that drivers could use to determine if they shouldn't drive. They could take a brief nap first. Although, this all may be moot if Google makes driver-less cars a reality.
Here is a link to recent statistics from the National Highway Traffic Safety Association citing that approximately one in four motor vehicle accidents is due to drowsy driving. Someday, sleep researchers may come up with a reliable and simple test of sleepiness that drivers could use to determine if they shouldn't drive. They could take a brief nap first. Although, this all may be moot if Google makes driver-less cars a reality.
Wednesday, August 13, 2014
Weight gain after tonsil removal for obstructive sleep apnea
Children with obstructive sleep apnea (OSA) can have reduced growth rates. The primary treatment of OSA in children is removing the tonsils adenoids, referred to as an adenotonsillectomy. After this procedure, studies have shown an increase in weight. However, some kids that are overweight before adenotonsillectomy put on even more weight after the surgery.
This study looked at two groups of children, ages 5-10 years old, who had OSA. One group got adenotonsillectomy and the other group received no treatment - just watchful waiting. Sleep studies and height / weight measurements were repeated 7 months later. Results showed that body weight and body mass index (BMI) increased in both groups of patients. This may be because the sleep apnea severity improved in both groups. It's unclear why that happened, especially with the weight gain. I would think that would make the sleep apnea severity worse in the untreated group.
What was remarkable about the study, however, was that after adjusting for baseline weight and other variables, the weight gain experienced by those that had the adenotonsillectomy was significantly greater than the group that received no treatment. In those children who were already overweight at the start of the study, 52% became obese after adenotonsillectomy vs 21% in the group that did not receive treatment. The researchers proposed several mechanisms for weight gain after adenotonsillectomy: increased calories consumed, unhealthy food choices, decreased energy burned due to reduced work of breathing, improvement in blood oxygen levels, and increased growth hormone secretion.
The authors recommend monitoring weight, nutritional counseling, and encouragement of physical activity after adenotonsillectomy for OSA in children.
This study looked at two groups of children, ages 5-10 years old, who had OSA. One group got adenotonsillectomy and the other group received no treatment - just watchful waiting. Sleep studies and height / weight measurements were repeated 7 months later. Results showed that body weight and body mass index (BMI) increased in both groups of patients. This may be because the sleep apnea severity improved in both groups. It's unclear why that happened, especially with the weight gain. I would think that would make the sleep apnea severity worse in the untreated group.
What was remarkable about the study, however, was that after adjusting for baseline weight and other variables, the weight gain experienced by those that had the adenotonsillectomy was significantly greater than the group that received no treatment. In those children who were already overweight at the start of the study, 52% became obese after adenotonsillectomy vs 21% in the group that did not receive treatment. The researchers proposed several mechanisms for weight gain after adenotonsillectomy: increased calories consumed, unhealthy food choices, decreased energy burned due to reduced work of breathing, improvement in blood oxygen levels, and increased growth hormone secretion.
The authors recommend monitoring weight, nutritional counseling, and encouragement of physical activity after adenotonsillectomy for OSA in children.
Wednesday, August 6, 2014
Sleep apnea surgery
Continuous positive airway pressure (CPAP) remains the most effective treatment for obstructive sleep apnea (OSA). As many of you may know, CPAP is not well tolerated and usage of CPAP remains a significant problem. Some patients decide to pursue upper airway surgery for their OSA. However, surgery tends to be the least effective option for adults. In children, surgery is often the treatment of choice - it works quite well in fact. In adults, the more common procedure is called a uvulopalatopharyngoplasty or UP3. This involves removing the tonsils, the uvula, and part of the soft palate. A newer procedure called coblation channeling of the tongue or CCT involves surgically reducing the volume of the tongue. This article discusses research out of Australia showing a combination of UP3 with CCT may be more effective than either procedure alone. This may provide better results to patients who suffer from OSA but can not tolerate CPAP.
Wednesday, July 30, 2014
Sleep-disordered breathing in pregnancy
I've blogged before here, here, and here about pregnancy and breathing disorders in sleep. We know that the prevalence of sleep-disordered breathing (SDB) symptoms increases the further along in the pregnancy. This could be due weight gain and swelling that occurs as pregnancy progresses.
Some studies have shown an association between SDB and pregnancy-related illnesses like high blood pressure, gestational diabetes, and pre-term birth. However, many of these studies relied on subjective assessment of SDB. This study was done to look at the relationship of objectively assessed SDB and certain pregnancy-related illnesses. A home sleep study was performed on pregnant women twice - once between 6 - 20 weeks and again between 28 - 37 weeks. Results showed that 30% of the pregnant women had SDB early pregnancy. However, there was no relationship between SDB and maternal high blood pressure (called preeclampsia), preterm birth, or extremes of birthweight (low or high). There was a relationship between SDB severity and risk of developing gestational diabetes, even after controlling for confounding factors like age, race, body-mass index, hx of chronic high blood pressure, etc.
Despite the observed relationship between sleep-disordered breathing and gestational diabetes, the study authors pointed out that there is no evidence that treatment of the SDB in the short term improves maternal or neonatal outcomes.
Some studies have shown an association between SDB and pregnancy-related illnesses like high blood pressure, gestational diabetes, and pre-term birth. However, many of these studies relied on subjective assessment of SDB. This study was done to look at the relationship of objectively assessed SDB and certain pregnancy-related illnesses. A home sleep study was performed on pregnant women twice - once between 6 - 20 weeks and again between 28 - 37 weeks. Results showed that 30% of the pregnant women had SDB early pregnancy. However, there was no relationship between SDB and maternal high blood pressure (called preeclampsia), preterm birth, or extremes of birthweight (low or high). There was a relationship between SDB severity and risk of developing gestational diabetes, even after controlling for confounding factors like age, race, body-mass index, hx of chronic high blood pressure, etc.
Despite the observed relationship between sleep-disordered breathing and gestational diabetes, the study authors pointed out that there is no evidence that treatment of the SDB in the short term improves maternal or neonatal outcomes.
Wednesday, July 23, 2014
What drowsy drivers do to remain alert
Driving drowsy is a big problem, and a discussion I have with my patients every day. Studies have shown that driving drowsy can be as dangerous as driving drunk. And the combination of alcohol with sleep deprivation is extremely dangerous. When I ask my patients what they do if they feel sleepy while driving, most tell me they do things that studies have shown are not helpful. Examples include rolling down the windows or turning the radio up. The first thing that I say is that if the patient feels sleepy, they should not drive or operate heavy machinery until they feel rested and wide awake. I then explain to them that if they get sleepy while driving, they should switch drivers or pull over to take a nap.
Here is a report on the top things drivers do to remain alert while driving. I got this information from a survey done by DMEautomotive. Some notable responses to what drivers do when they feel sleepy while driving include:
58% drink caffeine (not shown to be helpful)
39% open a sunroof or window (not shown to be helpful)
45% switch drivers (has been shown to be helpful IF the other driver is rested!)
23% pull over and take a nap (this is the THE most helpful thing a drowsy driver can do!)
As stated in the article, the best course of action for drowsy drivers is to pull over and take a nap. The only cure for sleepiness is more sleep! Please be safe on the road.
Here is a report on the top things drivers do to remain alert while driving. I got this information from a survey done by DMEautomotive. Some notable responses to what drivers do when they feel sleepy while driving include:
58% drink caffeine (not shown to be helpful)
39% open a sunroof or window (not shown to be helpful)
45% switch drivers (has been shown to be helpful IF the other driver is rested!)
23% pull over and take a nap (this is the THE most helpful thing a drowsy driver can do!)
As stated in the article, the best course of action for drowsy drivers is to pull over and take a nap. The only cure for sleepiness is more sleep! Please be safe on the road.
Wednesday, July 16, 2014
Sleep loss and psychosis
Sleep deprivation has interesting affects on our mental and physical functioning. For example, sleep deprivation tends to temporarily improve the mood of patients with depression. In fact, too little sleep can result in a manic episode in patients with bipolar disorder. This study showed that one full night of sleep depression can produce symptoms that resemble psychosis. Psychosis is a mental disorder where the person "breaks" with reality, and is part of the disorder called schizophrenia. The most common symptoms are hallucinations and delusions. The results of the study about sleep deprivation are remarkable because the psychotic symptoms occurred after only one night of sleep loss. But don't worry, the psychotic symptoms resolved completely after sleeping the next night. The researchers theorize that psychosis from sleep loss may possibly be used to study mental illness and medications used to treat mental illness.
Wednesday, July 9, 2014
Insomnia and high blood pressure
Primary insomnia means difficulty sleeping not due to another medical or sleep disorder. It's a common problem but has not been conclusively linked with increased risk of medical illness. It has been shown to increase risk of depression. Part of what I do when I treat chronic insomnia is to explain that insomnia by itself is not medically dangerous. The studies that have shown links between insomnia and medical problems have not distinguished primary from secondary insomnia. Insomnia secondary to obstructive sleep apnea (OSA) can increase risk for cardiovascular (CV) disease, but it's the OSA, not the insomnia that is raising the CV risk.
Here is an article confirming what's already known about primary insomnia and high blood pressure. The results showed no link between insomnia and high blood pressure, even for 'severe' insomnia.
Here is an article confirming what's already known about primary insomnia and high blood pressure. The results showed no link between insomnia and high blood pressure, even for 'severe' insomnia.
Wednesday, July 2, 2014
Positional therapy for obstructive sleep apnea
A subset of my patients with obstructive sleep apnea (OSA) have it only on their back. By this, I mean that I've documented with a sleep study that a patient has OSA when sleeping on their back, but no OSA when on their sides. In my experience, this type of OSA is rare and usually only in patients with normal weight. But these patients have a treatment option that does not work in a majority of OSA patients - positional therapy. This means that if the patient can sleep on their sides or stomach only, they greatly reduce their snoring and sleep apnea. The trick is to not sleep on their back - something hard to do if they are asleep! I usually advocate using pillows behind the back to keep the person from rolling onto their side.
The FDA has just cleared an interesting device for positional OSA. It's called Night Shift by Advanced Brain Monitoring. It's a small device worn around the neck at night. It detects position (probably by gyroscope) and causes mild vibrations when the wearer is on their back. The vibrations help the user roll over, but stay asleep. The device vibrates more vigorously if the person is not responding. Their have been some studies on this device and they report improvement in sleep quality, reduction of snoring volume, and reduction of OSA.
The FDA has just cleared an interesting device for positional OSA. It's called Night Shift by Advanced Brain Monitoring. It's a small device worn around the neck at night. It detects position (probably by gyroscope) and causes mild vibrations when the wearer is on their back. The vibrations help the user roll over, but stay asleep. The device vibrates more vigorously if the person is not responding. Their have been some studies on this device and they report improvement in sleep quality, reduction of snoring volume, and reduction of OSA.
Wednesday, June 25, 2014
Human growth hormone and sleep quality
Human growth hormone (HGH) is popular amongst some athletes who use it for performance enhancement. A significant amount of HGH is secreted at night when asleep. Sleep deprivation can reduce HGH levels. HGH levels also naturally decrease with age. HGH can be used to treat certain medical conditions, like Prader-Willi Syndrome, which can cause sleep problems. I've not seen it used however in otherwise healthy people to improve sleep quality.
This study did just that - subjects took HGH at bedtime and reported significant improvement in time to fall asleep. They also had less time awake in the middle of the night and woke more rested in the morning. No reason for why HGH may improve sleep quality is given. Perhaps scientists will discover a novel mechanism of action to help those with reduced sleep quality.
This study did just that - subjects took HGH at bedtime and reported significant improvement in time to fall asleep. They also had less time awake in the middle of the night and woke more rested in the morning. No reason for why HGH may improve sleep quality is given. Perhaps scientists will discover a novel mechanism of action to help those with reduced sleep quality.
Wednesday, June 18, 2014
Sleeping pills and heart failure
Patients with heart failure are at increased risk of having sleep difficulties. Sleep-related breathing difficulties like sleep apnea are also more common in heart failure patients. Here is a study that looked at sleeping pills and heart failure patients. Specifically, the researchers investigated the relationships between drugs prescribed at hospital discharge, going back into the hospital, and cardiovascular events in heart failure patients.
The results showed that sleeping pills increase the risk of cardiovascular events in heart failure patients by 8-fold. The type of sleeping pills that were most risky were the benzodiazepines like valium. At the end of the article, the researchers speculate that benzodiazepine sleep aids could reduce cardiac function or cause respiratory depression, and this could worsen any underlying sleep-related breathing disorders. The latter is certainly possible and underscores the importance of heart failure patients getting evaluated for sleep apnea. Prior to prescribing sleep aids, it's best to rule out sleep-related breathing disorders. If sleep apnea is present, that needs to be treated, rather than just giving sleep aids.
The results showed that sleeping pills increase the risk of cardiovascular events in heart failure patients by 8-fold. The type of sleeping pills that were most risky were the benzodiazepines like valium. At the end of the article, the researchers speculate that benzodiazepine sleep aids could reduce cardiac function or cause respiratory depression, and this could worsen any underlying sleep-related breathing disorders. The latter is certainly possible and underscores the importance of heart failure patients getting evaluated for sleep apnea. Prior to prescribing sleep aids, it's best to rule out sleep-related breathing disorders. If sleep apnea is present, that needs to be treated, rather than just giving sleep aids.
Wednesday, June 11, 2014
Sleep apnea and cardiovascular effects
Obstructive sleep apnea (OSA) is associated with high blood pressure and cardiac arrhythmias. When someone has a sleep apnea event, their heart rate typically slows down. Heart rate then speeds up during the subsequent recovery breaths. It's this repetitive slow-fast cycle during the night that is thought to contribute to arrhythmia. And research has shown that the more oxygen levels decrease during sleep apnea, the greater the risk to the heart and blood vessels. This study was done in a rat model of OSA. The results showed that the low oxygen levels from OSA damaged vital neurons in the rats' brains that regulate blood pressure and heart rate. This could explain why OSA increases risk of high blood pressure and cardiac rhythm problems. More research will be needed to determine if treating OSA can reverse the damage to those neurons.
Wednesday, June 4, 2014
Yawning may cool the brain
I sometimes get asked why we yawn and I am not sure. I was taught that it was to increase oxygen supply to the blood, but research has not demonstrated that definitively. This study showed that yawning may be a way that the brain gets cooled. Specifically researchers studied contagious yawning - that type of yawning which occurs when you see another person yawn. This is in contrast to spontaneous yawning. The results showed that contagious yawning was more common at warm temperatures. However, it was not more common at very hot temperatures, such as in Arizona in the summer.
Wednesday, May 28, 2014
CPAP improves blood sugar control
I've blogged before about how patients with obstructive sleep apnea (OSA) are at increased risk of developing diabetes. I've also written about how treating OSA can improve blood sugar control in diabetics. Here is another study that demonstrates long term use of CPAP (5 years) is associated with better control of blood sugar in diabetics. The study also showed that long term use of CPAP was associated with lower blood pressure and improved quality of life. The study authors concluded that CPAP use is a cost-effective treatment option for OSA.
Wednesday, May 21, 2014
Sudden Infant Death Syndrome
Sudden Infant Death Syndrome (SIDS) is the sudden, unexplainable death of a baby less than a year old. The baby usually dies in its sleep. Rates of SIDS have decreased, perhaps due to public health campaigns that emphasize having infants sleep on their back only. But researchers still don't know exactly why SIDS occurs. This article discusses new research showing that the brains of babies who have died of SIDS have a similar histological pattern to those of children who died of accidental asphyxiation. The research showed that the histological pattern of the SIDS babies was different than that of babies who died from head trauma or infection.
Wednesday, May 14, 2014
CPAP use and high blood pressure
Studies have shown that obstructive sleep apnea (OSA) is linked to high blood pressure (HTN). There was a paper in 2012 that was a meta-analysis showing that CPAP significantly reduced both systolic and diastolic blood pressure (DBP). When the researchers looked closer at the data, they discovered that the reduction in DBP occurred more often when the baseline DBP was high, as well as when the patient was excessively sleepy at baseline. The results did not show that reduction in blood pressure was associated with the OSA severity.
In this study, the researchers went back over the original data to further explore the relationship between blood pressure improvement and CPAP therapy. The results showed that the sole predictor of reduction in blood pressure was the presence of uncontrolled HTN at baseline. Again, OSA severity was not related to the reduction in blood pressure seen with CPAP therapy. Also, excessive sleepiness was not a significant predictor in CPAP reducing blood pressure, in contrast to the prior study.
The researchers concluded that patients with OSA who have uncontrolled HTN would have the largest benefit in their blood pressure with CPAP therapy, despite how severe the OSA or how sleepy the person may or may not be.
In this study, the researchers went back over the original data to further explore the relationship between blood pressure improvement and CPAP therapy. The results showed that the sole predictor of reduction in blood pressure was the presence of uncontrolled HTN at baseline. Again, OSA severity was not related to the reduction in blood pressure seen with CPAP therapy. Also, excessive sleepiness was not a significant predictor in CPAP reducing blood pressure, in contrast to the prior study.
The researchers concluded that patients with OSA who have uncontrolled HTN would have the largest benefit in their blood pressure with CPAP therapy, despite how severe the OSA or how sleepy the person may or may not be.
Wednesday, May 7, 2014
Blood sugar and fat metabolism in narcoleptics treated with sodium oxybate
Narcolepsy is a neurological disorder characterized by excessive sleepiness. It's caused by destruction of a group of neurons in a part of our brain called the hypothalamus. The hypothalamus is important in regulating our hormones, many of which control basic functions like sleep and hunger. Because of the location in the brain, reports have linked narcolepsy to elevated weight and even type 2 diabetes. It's been theorized that patients with narcolepsy have reduced sensitivity to insulin, much like type 2 diabetics.
This study was done to assess both blood sugar and fat metabolism in a small group of narcoleptics and compared them to a matched control group that did not have narcolepsy. They used a sophisticated test to measure both fat and blood sugar metabolism, something that had not been done before in older studies of patients with narcolepsy. The results were interesting in that the researchers found that narcoleptics had increased insulin sensitivity in the periphery - the opposite of what they expected. Liver cell insulin sensitivity and pancreatic function were the same as matched controls. Fat metabolism tended to be lower in patients with narcolepsy, which may explain in part why narcolepsy is linked with being overweight.
The researchers also treated the narcoleptic patients with sodium oxybate, a medicine that improves some of the narcolepsy symptoms. It's taken at night, and improves the patients' sleep quality, although it's not a sleep aid. Interestingly, the sodium oxybate increased fat metabolism, and the narcoleptic patients lost an average of 5.2 kg (11.5 pounds) in the three months of the study. The exact mechanism of the weight loss is not known.
The bottom line is that the results of this study do not support an increased risk of type 2 diabetes in narcoleptics. Also, patients with narcolepsy that are treated with sodium oxybate may lose weight, although the exact mechanism is unclear.
This study was done to assess both blood sugar and fat metabolism in a small group of narcoleptics and compared them to a matched control group that did not have narcolepsy. They used a sophisticated test to measure both fat and blood sugar metabolism, something that had not been done before in older studies of patients with narcolepsy. The results were interesting in that the researchers found that narcoleptics had increased insulin sensitivity in the periphery - the opposite of what they expected. Liver cell insulin sensitivity and pancreatic function were the same as matched controls. Fat metabolism tended to be lower in patients with narcolepsy, which may explain in part why narcolepsy is linked with being overweight.
The researchers also treated the narcoleptic patients with sodium oxybate, a medicine that improves some of the narcolepsy symptoms. It's taken at night, and improves the patients' sleep quality, although it's not a sleep aid. Interestingly, the sodium oxybate increased fat metabolism, and the narcoleptic patients lost an average of 5.2 kg (11.5 pounds) in the three months of the study. The exact mechanism of the weight loss is not known.
The bottom line is that the results of this study do not support an increased risk of type 2 diabetes in narcoleptics. Also, patients with narcolepsy that are treated with sodium oxybate may lose weight, although the exact mechanism is unclear.
Wednesday, April 30, 2014
Insomnia and stroke
Sleep duration and cardiovascular disease gets lots of press, even though the studies are inconclusive. Some speculate a "U" shaped curve where too little sleep and too much sleep is associated with higher risk of cardiovascular disease. It's unclear, but insomnia gets linked to sleep deprivation, and thus the news runs with stories that insomnia can increase risk of cardiovascular disease. I have blogged about it multiple times, here, here, and here. There are relatively few studies that have examined the relationship between insomnia and stroke.
This study is a retrospective cohort study based in Taiwan. They looked at patients with a diagnosis of insomnia, and used a comparison group without insomnia. They excluded those patients with a known diagnosis of obstructive sleep apnea and those with previous diagnosis of stroke. Then they tracked the populations for 4 years to analyze the number of strokes that occurred. There were 21,438 subjects with insomnia diagnoses and 64,314 subjects without insomnia. As expected, prevalence of diabetes, high blood pressure, high cholesterol, depression, anxiety, and atrial fibrillation were all higher in the insomnia population. During the 4 year follow up period, 583 of the insomnia patients developed stroke, whereas 962 of the patients without insomnia developed stroke. The incidence rate was significantly higher in the insomnia patient group than in the group without insomnia.
Again, there are some important limitations in this study, some of which are not addressed by the study authors. One big one is that we really don't know if the patients had primary or secondary insomnia. For all we know, the patients with insomnia and stroke may all have had undiagnosed obstructive sleep apnea. Also, the researchers relied on a diagnosis code for insomnia, but that does not mean these patients had a clinical interview by a sleep physician to determine that diagnosis. We don't know who is making the diagnosis of insomnia or how it is being made. There seems to be too many details left out to make any reasonable conclusions. I do agree with the authors that we need to screen and treat insomnia. It's also important to make an accurate diagnosis.
The reason I harp on this topic is that many of my patients with chronic insomnia inadvertently worsen their insomnia by worrying about the supposed health effects of insomnia. The news media and magazine articles make "insomnia" sound so dangerous. But if these individuals have primary insomnia, then they are not necessarily at increased risk just from the insomnia alone.
This study is a retrospective cohort study based in Taiwan. They looked at patients with a diagnosis of insomnia, and used a comparison group without insomnia. They excluded those patients with a known diagnosis of obstructive sleep apnea and those with previous diagnosis of stroke. Then they tracked the populations for 4 years to analyze the number of strokes that occurred. There were 21,438 subjects with insomnia diagnoses and 64,314 subjects without insomnia. As expected, prevalence of diabetes, high blood pressure, high cholesterol, depression, anxiety, and atrial fibrillation were all higher in the insomnia population. During the 4 year follow up period, 583 of the insomnia patients developed stroke, whereas 962 of the patients without insomnia developed stroke. The incidence rate was significantly higher in the insomnia patient group than in the group without insomnia.
Again, there are some important limitations in this study, some of which are not addressed by the study authors. One big one is that we really don't know if the patients had primary or secondary insomnia. For all we know, the patients with insomnia and stroke may all have had undiagnosed obstructive sleep apnea. Also, the researchers relied on a diagnosis code for insomnia, but that does not mean these patients had a clinical interview by a sleep physician to determine that diagnosis. We don't know who is making the diagnosis of insomnia or how it is being made. There seems to be too many details left out to make any reasonable conclusions. I do agree with the authors that we need to screen and treat insomnia. It's also important to make an accurate diagnosis.
The reason I harp on this topic is that many of my patients with chronic insomnia inadvertently worsen their insomnia by worrying about the supposed health effects of insomnia. The news media and magazine articles make "insomnia" sound so dangerous. But if these individuals have primary insomnia, then they are not necessarily at increased risk just from the insomnia alone.
Wednesday, April 23, 2014
Obstructive sleep apnea and growth hormone
Growth hormone (GH) is secreted at night during our deepest levels of sleep. As the name implies, GH is involved in growth of our bodies. Too much GH as a child can result in a condition called acromegaly. The actor Richard Kiel, who played the character Jaws in two of the James Bond movies, has this condition. Too little GH can also negatively impact cardiovascular health as well as effect carbohydrate, fat, and lipid metabolism. GH is part of a group of hormones that include Insulin-like growth factor-1 (IGF-1) and IGF-1 binding proteins.
Obstructive sleep apnea (OSA) could reduce GH secretion due to the brief arousals from sleep, especially deep sleep. OSA can also affect GH levels by the repetitive oxygen level drops. It's been theorized that regular CPAP use may reverse the effects of OSA on GH. Previous studies have been inadequate to answer this question definitively. This study sought to determine if long term CPAP affects GH levels.
Researchers performed a randomized, double-blind, sham-controlled parallel group study. The participants were all men with moderate to severe OSA. They were randomized to receive either 12 weeks of real or sham CPAP. At the end of the 12 week period, all participants were put on real CPAP for another 12 weeks. The results showed that GH secretion was higher in those treated with real CPAP for 12 weeks compared to sham CPAP. Interestingly, the increase in GH was not due to improvements in the amount of deep sleep. Instead, the improvements in GH were associated with reduction in the oxygen level drops. Another interesting result was that the participants used real CPAP only 3.6 +/- 1.9 hours per night and the sham CPAP only 2.8 +/- 2.1 hours per night. Since most people sleep 7-8 hours per night, that amount of CPAP usage is low, yet the therapy still seemed to have a positive effect on GH.
Obstructive sleep apnea (OSA) could reduce GH secretion due to the brief arousals from sleep, especially deep sleep. OSA can also affect GH levels by the repetitive oxygen level drops. It's been theorized that regular CPAP use may reverse the effects of OSA on GH. Previous studies have been inadequate to answer this question definitively. This study sought to determine if long term CPAP affects GH levels.
Researchers performed a randomized, double-blind, sham-controlled parallel group study. The participants were all men with moderate to severe OSA. They were randomized to receive either 12 weeks of real or sham CPAP. At the end of the 12 week period, all participants were put on real CPAP for another 12 weeks. The results showed that GH secretion was higher in those treated with real CPAP for 12 weeks compared to sham CPAP. Interestingly, the increase in GH was not due to improvements in the amount of deep sleep. Instead, the improvements in GH were associated with reduction in the oxygen level drops. Another interesting result was that the participants used real CPAP only 3.6 +/- 1.9 hours per night and the sham CPAP only 2.8 +/- 2.1 hours per night. Since most people sleep 7-8 hours per night, that amount of CPAP usage is low, yet the therapy still seemed to have a positive effect on GH.
Wednesday, April 16, 2014
Sleep is the new frontier of medicine
This week I am just posting a link to an article that discusses how sleep is the new frontier in medicine. It's a nice review of the importance of sleep, and how sleep affects so many different aspects of our physical and mental health.
Wednesday, April 9, 2014
Sleep loss and metabolic syndrome
Metabolic syndrome is a chronic disorder characterized by abdominal obesity, impaired blood sugar metabolism, high cholesterol, and high blood pressure. Here is an article about sleep loss and it's affect on our metabolism. The article is a review of the observational studies that examine the relationship between sleep deprivation and metabolic syndrome. The authors discuss some of the studies that show that acute sleep loss is linked with obesity, type 2 diabetes, cholesterol problems, high blood pressure, and even death. Of note, some of the studies show increased rates of some of these issues when people report sleeping less than or more than a specified "normal" amount of sleep. So it's not just sleep loss that is linked to problems, including mortality.
The authors note that sleep loss can affect appetite, food intake, physical activity levels, and energy expenditure. Again, these are short term studies and the reasons for the changes are not entirely clear. Results sometimes are conflicting, such as some studies showing higher levels, and other studies showing lower levels of appetite regulating hormones.
The authors conclude that sleep loss may be a "promising target for the prevention, and probably the treatment, of the metabolic syndrome and its components." Perhaps that is the case, but telling people to get more sleep is unlikely to improve their metabolic syndrome. It's certainly more complicated than that. Diet and exercise are just as important, and most likely much more so than just getting more sleep. I concede that insufficient sleep may contribute a small part to metabolic syndrome, but more long term studies are needed. And I agree with the authors when they conclude that ongoing and future studies will show whether interventions to improve sleep duration and quality can prevent or even reverse adverse metabolic traits."
The authors note that sleep loss can affect appetite, food intake, physical activity levels, and energy expenditure. Again, these are short term studies and the reasons for the changes are not entirely clear. Results sometimes are conflicting, such as some studies showing higher levels, and other studies showing lower levels of appetite regulating hormones.
The authors conclude that sleep loss may be a "promising target for the prevention, and probably the treatment, of the metabolic syndrome and its components." Perhaps that is the case, but telling people to get more sleep is unlikely to improve their metabolic syndrome. It's certainly more complicated than that. Diet and exercise are just as important, and most likely much more so than just getting more sleep. I concede that insufficient sleep may contribute a small part to metabolic syndrome, but more long term studies are needed. And I agree with the authors when they conclude that ongoing and future studies will show whether interventions to improve sleep duration and quality can prevent or even reverse adverse metabolic traits."
Wednesday, April 2, 2014
9/11 and sleep apnea
Here is an article about how workers who were first responders to 9/11 have elevated risk of sleep apnea and post-traumatic stress disorder (PTSD). The article does not go into detail about the mechanism of action. I wonder if the rate of sleep apnea is higher due to localized inflammation in the upper airway due to the particulate matter inhaled at the scene. I could also envision higher rates of pulmonary disease from inhalation of particulates, but that was not mentioned in the article.
Wednesday, March 26, 2014
Blood sugar control and obstructive sleep apnea
Human sleep can be divided into two different stages, non-REM sleep and REM sleep. During REM sleep is when most dreaming occurs. And while we dream, our brain temporarily paralyzes our muscles to minimize potential harm that would occur if we acted out the dreams we had. However, when the throat muscles get paralyzed in REM sleep, the throat becomes even more floppy, and obstructive sleep apnea (OSA) can be more severe. In some patients, the difference in OSA severity from NREM to REM is quite striking - some patients have OSA confined almost exclusively to those periods of REM sleep.
Some sleep researchers feel that OSA confined only to REM sleep may not be as serious as OSA that is present in both stages of sleep, as I have blogged about before. But in my experience, patients that treat their REM sleep-related OSA often have an improved quality of life.
This article showed that the more severe the OSA is in REM sleep, the worse control of diabetes. It's not clear why that would be, but the findings do not support the thinking that REM sleep OSA is less serious. The study authors point out that since most REM sleep occurs in the second half of the night, patients who don't use their CPAP all night may be at greater risk of having less control of their blood sugars.
Some sleep researchers feel that OSA confined only to REM sleep may not be as serious as OSA that is present in both stages of sleep, as I have blogged about before. But in my experience, patients that treat their REM sleep-related OSA often have an improved quality of life.
This article showed that the more severe the OSA is in REM sleep, the worse control of diabetes. It's not clear why that would be, but the findings do not support the thinking that REM sleep OSA is less serious. The study authors point out that since most REM sleep occurs in the second half of the night, patients who don't use their CPAP all night may be at greater risk of having less control of their blood sugars.
Wednesday, March 19, 2014
Weight loss and obstructive sleep apnea
Most people I see already know that obstructive sleep apnea (OSA) is related, at least in part, to elevated weight. Many of my patients start coming to my clinic for help after their OSA symptoms have worsened. Almost all of them report weight gain that occurred as the OSA symptoms worsened. Part of my treatment options, at least for mild to moderate OSA is weight reduction. Easier said than done, however. And if my patient has severe OSA, weight loss alone may not be enough to eliminate their OSA.
This study confirms what I said above. It showed that even moderate weight loss, if maintained, can eliminate mild OSA. The key here is maintaining the weight loss. Many of my patients are able to temporarily drop weight, only to regain it again.
This study confirms what I said above. It showed that even moderate weight loss, if maintained, can eliminate mild OSA. The key here is maintaining the weight loss. Many of my patients are able to temporarily drop weight, only to regain it again.
Wednesday, March 12, 2014
Obstructive sleep apnea and multiple sclerosis
Multiple sclerosis (MS) is a neurological disease thought to be an autoimmune disorder. It causes a variety of symptoms, with a common one being fatigue. Obstructive sleep apnea (OSA) also can cause fatigue. This study sought to examine the relationship between fatigue, MS, and OSA. It was performed at University of Michigan's Neurology Department. MS patients were surveyed about OSA and fatigue. Results showed that 1 out of 5 MS patients reported a diagnosis of OSA. This is higher in the general population. Also, the researchers found that an even higher proportion of MS patients were at risk for having OSA based on a commonly administered questionnaire (the STOP-Bang). Finally, OSA was a predictor of fatigue after adjusting for other clinical and sleep related predictors of fatigue.
What the results mean is that neurologists and other physicians who care for patients with MS should not use the MS as the only reason for a patient's persistent fatigue. OSA could be contributing and the patient may benefit from a sleep evaluation. OSA is treatable and some of the fatigue may improve with OSA therapy.
What the results mean is that neurologists and other physicians who care for patients with MS should not use the MS as the only reason for a patient's persistent fatigue. OSA could be contributing and the patient may benefit from a sleep evaluation. OSA is treatable and some of the fatigue may improve with OSA therapy.
Wednesday, March 5, 2014
Obstructive sleep apnea and cardiovascular disease
Research has shown that obstructive sleep apnea (OSA) increases risk of cardiovascular disease - possibly by multiple pathways - repeated oxygen level drop offs, broken up sleep, chronic hyperactivity of central nervous system, and systemic inflammation. However, the studies have looked only at the apnea-hypopnea index (AHI) as a marker for OSA severity. AHI is good for this, as it tells me how many times per hour your airway collapsed, but it does not tell me about oxygen levels or sleep quality. So researchers did this study to address this issue. Specifically, they studied >10,000 people with a wide variety of OSA severity. They examined the relationship between OSA related variables and cardiovascular outcomes as well as all-cause mortality. They even controlled for traditional cardiovascular risk factors like gender, age, body mass index, etc. The results were surprising - the AHI did not correlate with cardiovascular outcomes when controlling for the potential confounders. However, other related variables did correlate - things such as amount of time asleep with oxygen saturations < 90%, the number of awakenings, mean heart rate, total sleep time, and presence of excessive daytime sleepiness. Specifically, the time spent asleep with oxygen saturations less than 90% increased risk of cardiovascular event or death by 50%.
Wednesday, February 26, 2014
Restless legs syndrome and parkinson disease
I was taught that Restless legs syndrome (RLS) is not related to Parkinson Disease (PD), even though they can be treated with similar medications. However, here is a study that shows a potential relationship between RLS and PD. Researchers studied almost 23,000 men with self-reported RLS and documented PD. The results showed that RLS symptoms were associated with higher risk of developing PD during the first 4 years of follow up. This relationship was only statistically significant in the men with severe RLS symptoms, occurring 15 or more times per month.
The researchers speculate that RLS may be an early feature of PD, and be a distinct entity from RLS that is not associated with PD.
The researchers speculate that RLS may be an early feature of PD, and be a distinct entity from RLS that is not associated with PD.
Wednesday, February 19, 2014
Sleep fragmentation and cancer
Some studies have linked obstructive sleep apnea (OSA) to cancer. This study shows that sleep fragmentation in mice was associated with larger, more aggressive tumors than mice that did not have sleep fragmentation. Since I don't have access to the full article, it's unclear how the sleep fragmentation was produced. Also, OSA can cause sleep fragmentation but also low oxygen levels, and low oxygen could be linked to tumors. Either way, it's thought that OSA causes a systemic inflammatory response, and this may be what is linked to cancer.
Wednesday, February 12, 2014
Low testosterone and sleep apnea
Foxnews has two articles about low testosterone (here and here). The diagnosis is being made more frequently and many more men are receiving testosterone therapy. I'm not writing about this topic to weigh in on the supposed controversy, but just to point out that neither article mentions the fact that obstructive sleep apnea (OSA) can be related to low testosterone. Specifically, untreated OSA may reduce testosterone levels. Also, OSA causes fatigue and sleepiness, and thus could mimic the symptoms of low testosterone. Therefore, if you suspect you have low testosterone or are diagnosed with low testosterone by your doctor, consider getting evaluated for obstructive sleep apnea if you snore regularly or have witnessed pauses in your breathing.
Wednesday, February 5, 2014
L-Carnitine and narcolepsy
Narcolepsy is a sleep disorder that causes excess sleepiness. Recently, a study has shown that narcolepsy may be associated with low levels of a compound called carnitine, which is involved in fatty acid metabolism. This study looked at the effects of supplementing L-carnitine in 28 patients with narcolepsy. The study was a randomized, double-blinded, cross-over, and placebo-controlled design that lasted 16 weeks. The participants took 340 mg of L-carnitine in the morning and 170 mg of L-carnitine in the evening. The participants were allowed to take traditional medications for narcolepsy. The primary outcome measure was the patient's subjective assessment of their sleepiness, which was based on the total time the person reported they dozed off during the daytime as recorded in their sleep logs. Of note, there was no objective measurement of sleepiness, such a multiple sleep latency test.
Results showed a statistically significant reduction in subjective dozing time when participants took L-carnitine. Specifically, participants dozed for 49 +/- 34 minutes / day on L-carnitine versus 58 +/- minutes per day on placebo. This may be statistically significant, but I wonder how clinically significant it is. Researchers reported no side effects to the L-carnitine.
The researchers also noted that low carnitine levels may be seen in chronic fatigue syndrome, and that it's been reported that L-carnitine supplementation resulted in significant improvement in fatigue severity after two months of use.
Results showed a statistically significant reduction in subjective dozing time when participants took L-carnitine. Specifically, participants dozed for 49 +/- 34 minutes / day on L-carnitine versus 58 +/- minutes per day on placebo. This may be statistically significant, but I wonder how clinically significant it is. Researchers reported no side effects to the L-carnitine.
The researchers also noted that low carnitine levels may be seen in chronic fatigue syndrome, and that it's been reported that L-carnitine supplementation resulted in significant improvement in fatigue severity after two months of use.
Wednesday, January 29, 2014
Melatonin and Prostate Cancer
Melatonin is the hormone produced by your brain when it gets dark - it tells your brain it's time to sleep. This study analyzed levels of a melatonin metabolite in the urine of older men from Iceland. The results showed that melatonin metabolite levels were lowest in those that reported sleep aid use, trouble falling asleep, or trouble staying asleep. And those men that had the highest levels of the metabolite had a 75% decreased risk of advanced prostate cancer.
The article does not discuss possible mechanisms, and more studies are needed before melatonin is recommended to ward off prostate cancer.
The article does not discuss possible mechanisms, and more studies are needed before melatonin is recommended to ward off prostate cancer.
Wednesday, January 22, 2014
Using your smartphone to evaluate snoring and obstructive sleep apnea
In sleep medicine, there is a push to move the diagnosis of sleep apnea from the sleep lab to the patient's home. Home sleep studies are done routinely in certain regions of the US - the northeast and west coast, specifically.
Smartphones can do many things these days. These researchers from Japan developed an app for an Android phone that can monitor snoring and even obstructive sleep apnea. The app did this by measuring sound from the patient. Snoring was measured in a similar way that it is done in a sleep lab. But sleep apnea was measured in a novel way - by counting the number of "dips" in sound during recording. The app was tested alongside a standard in-lab sleep study and found to be relatively accurate.
The authors point out that the study has limitations...the first being that the subjects who tested the app were suspected of having sleep apnea. So more research is needed to see if this app would work in the general population as a screening tool. Also, how would the smartphone react if the patient and their bedpartner were snoring? Perhaps the bedpartner could sleep in a separate room for a night to allow the app to evaluate only the patient. The last limitation was that the correlation between sleep apnea severity detected by the app and the in-lab sleep study was not as good when the patient has mild to moderate sleep apnea. It was more accurate for severe sleep apnea.
The authors propose that an app like this could be used less for diagnosis, and more for monitoring changes in snoring as patients change their sleeping position or lose weight. In a commentary after the original article, it was suggested that the app could be used in combination with the phone's accelerometer to alert a patient that they are on their back and snoring. The patient would then roll on their sides again. I can envision an app like this combined with a wire that measures oxygen levels and pulse rate to make a diagnosis at home. This could be an even cheaper home study than what is available now.
Smartphones can do many things these days. These researchers from Japan developed an app for an Android phone that can monitor snoring and even obstructive sleep apnea. The app did this by measuring sound from the patient. Snoring was measured in a similar way that it is done in a sleep lab. But sleep apnea was measured in a novel way - by counting the number of "dips" in sound during recording. The app was tested alongside a standard in-lab sleep study and found to be relatively accurate.
The authors point out that the study has limitations...the first being that the subjects who tested the app were suspected of having sleep apnea. So more research is needed to see if this app would work in the general population as a screening tool. Also, how would the smartphone react if the patient and their bedpartner were snoring? Perhaps the bedpartner could sleep in a separate room for a night to allow the app to evaluate only the patient. The last limitation was that the correlation between sleep apnea severity detected by the app and the in-lab sleep study was not as good when the patient has mild to moderate sleep apnea. It was more accurate for severe sleep apnea.
The authors propose that an app like this could be used less for diagnosis, and more for monitoring changes in snoring as patients change their sleeping position or lose weight. In a commentary after the original article, it was suggested that the app could be used in combination with the phone's accelerometer to alert a patient that they are on their back and snoring. The patient would then roll on their sides again. I can envision an app like this combined with a wire that measures oxygen levels and pulse rate to make a diagnosis at home. This could be an even cheaper home study than what is available now.
Wednesday, January 15, 2014
CPAP and Parkinson's Disease
Patient's with Parkinson's Disease often have difficulty staying asleep. They are also sleepy. This can be due to the disease or some of the Parkinson's medications. Obstructive sleep apnea (OSA) is also common in Parkinson's Disease. This may be due, in part, to loss of neuromuscular control of the upper airway muscles - allowing the throat to collapse easier.
This study looked at patients with Parkinson's Disease that had OSA. They gave the patients CPAP and placebo CPAP, monitored nightly use, and measured sleepiness objectively. The results showed that CPAP deepened sleep and reduced daytime sleepiness. Patients were able to use the CPAP consistently despite having the motor control problems common in Parkinson's Disease. Interestingly, CPAP use did not reduce the amount of time spent awake after initially falling asleep. The authors point out that this points to the inherent sleep difficulties of Parkinson's patients, even after their OSA is treated.
This study looked at patients with Parkinson's Disease that had OSA. They gave the patients CPAP and placebo CPAP, monitored nightly use, and measured sleepiness objectively. The results showed that CPAP deepened sleep and reduced daytime sleepiness. Patients were able to use the CPAP consistently despite having the motor control problems common in Parkinson's Disease. Interestingly, CPAP use did not reduce the amount of time spent awake after initially falling asleep. The authors point out that this points to the inherent sleep difficulties of Parkinson's patients, even after their OSA is treated.
Wednesday, January 8, 2014
Sleep and Our Health
Here is an interesting summary article about the importance of sleep and our health. The author discusses how sleep affects memory, the endocrine system, the immune system, and psychiatric disorders. The author uses quotes from a Harvard sleep researcher, Dr. Stickgold, who explains some of the recent findings about sleep and health.
I thought his description of dream importance was a little confusing. In the beginning, he suggests dreams are "much, much less important" than once thought. Then he describes how dreams help us remember and organize recent events. Perhaps he means dreams are less important with regard to analysis of the unconscious?
I thought his description of dream importance was a little confusing. In the beginning, he suggests dreams are "much, much less important" than once thought. Then he describes how dreams help us remember and organize recent events. Perhaps he means dreams are less important with regard to analysis of the unconscious?
Thursday, January 2, 2014
Sleep and technology
This article discusses the findings from the National Sleep Foundation's Sleep in America Poll from 2011. Some of the questions involved sleep quality and use of technology in the hour leading up to trying to sleep. The results showed that using stimulating technology that was interactive, like video games, cell phones, and computers was more disruptive to sleep than passive technology like watching TV or listening to music. The authors speculate that using stimulating technology may prevent the natural withdrawal of the sympathetic nervous system activity that is needed for sleep onset.
The implications of this research are intriguing. The results challenge, at least in part, that using passive technology in the bed can disrupt sleep. What seems to be most disruptive to sleep is stimulating technology. These findings could be extrapolated to other stimulating activities performed in the hour before bedtime, whether technology is involved or not. So perhaps the rule that the bed should be used for sleep only needs to be modified - it's possible that passive activity is not necessarily going to disrupt sleep. This goes along with my clinical experience in treating patients with chronic insomnia. Some of them have been going to sleep with the TV on in their bedroom since middle or high school. Yet their insomnia does not start for several years later, often in their late 20's. In these individuals, watching TV in the bedroom may not negatively impacting sleep quality as once thought.
The implications of this research are intriguing. The results challenge, at least in part, that using passive technology in the bed can disrupt sleep. What seems to be most disruptive to sleep is stimulating technology. These findings could be extrapolated to other stimulating activities performed in the hour before bedtime, whether technology is involved or not. So perhaps the rule that the bed should be used for sleep only needs to be modified - it's possible that passive activity is not necessarily going to disrupt sleep. This goes along with my clinical experience in treating patients with chronic insomnia. Some of them have been going to sleep with the TV on in their bedroom since middle or high school. Yet their insomnia does not start for several years later, often in their late 20's. In these individuals, watching TV in the bedroom may not negatively impacting sleep quality as once thought.
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