A lack of sleep doesn’t just leave you cranky and spoiling for a fight. Researchers at The Ohio State University Institute for Behavioral Medicine Research say it also puts you at risk for stress-related inflammation.
This type of inflammation is associated with higher risk of cardiovascular disease, diabetes, arthritis, and other diseases.
“We know sleep problems are also linked with inflammation and many of the same chronic illnesses. So we were interested to see how sleep-related to inflammation among married couples, and whether one partner’s sleep affected the other’s inflammation,” says Stephanie Wilson, PhD, lead researcher on the study, in a release.
Results of the study were published in the journal Psychoneuroendocrinology.
The research team recruited 43 couples that completed 2 study visits. Each time, the couples provided blood samples and said how many hours they had slept the previous two nights. Then researchers had the couples try to resolve a topic that sparks conflict in their marriage. Blood samples were taken again following the discussion.
“We found that people who slept less in the past few nights didn’t wake up with higher inflammation, but they had a greater inflammatory response to the conflict. So that tells us less sleep increased vulnerability to a stressor,” Wilson says.
If both partners got less than 7 hours of sleep the previous 2 nights, the couple was more likely to argue or become hostile. For every hour of sleep lost, the researchers noted that levels of two known inflammatory markers rose 6%. Couples who used unhealthy tactics in their disagreement had an even greater inflammatory response—about a 10% increase with each hour of less sleep.
“Any increase isn’t good, but a protracted increase that isn’t being addressed is where it can become a problem,” Wilson says. “What’s concerning is both a lack of sleep and marital conflict are common in daily life. About half of our study couples had slept less than the recommended 7 hours in recent nights.”
“Part of the issue in a marriage is that sleep patterns often track together. If one person is restless, or has chronic problems, that can impact the other’s sleep. If these problems persist over time, you can get this nasty reverberation within the couple,” says Janice Kiecolt-Glaser, PhD, senior author and director of the Institute for Behavioral Medicine Research.
Researchers were encouraged to see that there was a protective effect if one of the partners was well rested, or discussed conflict in a healthy way. They tended to neutralize the disagreement that might be stirred by the sleep-deprived partner.
“We would tell people that it’s important to find good ways to process the relationship and resolve conflict—and get some sleep,” Kiecolt-Glaser says.
Updated July 6th 2017
A study of U.S. adults in 19 states and the District of Columbia revealed that 4.2 percent of drivers fell asleep behind the wheel within the previous month before being surveyed, the Centers for Disease Control Prevention reported Thursday.
The revealing report showed the dangers of not getting enough sleep and operating a vehicle. People who said they snored or slept less than six hours a day were more likely to report sleeping while driving.
The National Highway Traffic Safety Administration (NHTSA) said that 2.5 percent of all fatal motor crashes and 2.0 percent of all non-fatal crashes involved drowsy driving, according to the authors.
The AAA Foundation for Traffic Safety estimates that more than 16 percent of fatal crashes involve a drowsy driver.
However, the percentage could be as high as 33 percent since data collection can be difficult.
The CDC surveyed 147,076 people 18 and older in Arkansas, California, Connecticut, Delaware, Georgia, Hawaii, Illinois, Kansas, Louisiana, Maryland, Michigan, Minnesota, Missouri, Nebraska, Nevada, New York, Oregon, Texas and Wyoming in 2009 and/or 2010 using the agency’s ongoing Behavioral Risk Factor Surveillance System (BRFSS).
Survey takers were asked whether they had fallen asleep while driving — otherwise known as drowsy driving — in the last 30 days, how often they dozed off during the day, how rested they felt and about their regular sleeping habits.
Men were more likely to sleep while driving than women (5.3 percent versus 3.2 percent), while younger drivers were more likely to doze off then older ones (more than 4.9 percent of the 18-44 year old group compared to 1.7 percent of the 65 and older group).
Non-Hispanic whites were less likely to admit to driving while drowsy (3.2 percent versus 6.1 percent of non-Hispanic blacks, 5.9 percent of Hispanics and 6.0 percent of all other races/ethnicities).
Kent Smith DDS, D-ABDSM President at American Sleep And Breathing Academy
Updated July 17th 2017
AHI stands for apnea-hypopnea index which is a scale that indicates if you have apnea, a potentially serious sleep disorder in which breathing repeatedly stops and starts.
The AHI is an important calculation made based on the results of a standard overnight sleep study called a polysomnogram or in home sleep apnea testing. As part of these tests, there are sensors placed in the nose or near the mouth that measure air movement.
There are also belts positioned across the chest and stomach that stretch as breathing occurs. Apnea events occur when the airway becomes completely obstructed and no airflow is detected by the nose and mouth despite effort occurring as measured by the chest and abdominal belts.
If the airflow is reduced only partially, but by at least 30 percent as estimated based on a graph of the signal, it is called a hypopnea.
These events are thought to be significant when they occur in the context of two other events: oxygen level drops or arousals from sleep. The oxygenation of the blood is measured with an oximeter, a small sensor that shines a red light through the fingertip.
When the oxygen level falls, this is called a desaturation, and drops of at least 3 percent are problematic. Standard sleep studies also record arousals from deep to light sleep and even awakenings with an electroencephalogram (EEG). These awakenings may fragment sleep, make it unrefreshing, and lead to daytime sleepiness.
Apneas and hypopneas are interpreted as disruptive when paired with either oxygen desaturations or arousals.
The AHI is an averaged measure. It is calculated by taking the total number of significant apnea or hypopnea events divided by the total amount of time spent asleep in hours.
In other words, it is the number of times per hour of sleep (or recording) that the airway partially or completely collapsed, leading to significant drops in the oxygen levels of the blood or arousals from a deeper to a lighter stage of sleep.
If your AHI is 15, this means that, on average, 15 times per hour of sleep your breathing was compromised and this led to adverse consequences.
There are some sleep facilities that use other measures to assess this degree of severity. The respiratory-disturbance index (RDI) may be used if a measurement of airway resistance with a pressure esophageal manometer is also included in the study.
The oxygen-desaturation index (ODI) attempts to calculate the number of apnea or hypopnea events per hour that lead to an oxygen drop of at least 3 percent.
This is thought to be important in assessing the risk of long-term cardiovascular (high blood pressure, heart attack, and heart failure) or neurocognitive (stroke and dementia) consequences.
If your sleep study does not contain these more specific measures, this is nothing to worry about.
How does the numeric value as reported by an AHI correlate with the severity of sleep apnea? Although the standards are widely accepted throughout the field of sleep medicine, the cutoffs for each classification are admittedly somewhat arbitrary. Based on research, the following groupings are used in adults:
In general, these measures are of added significance if there is evidence of other adverse effects from sleep apnea, including an elevation in the Epworth sleepiness scale above 10, a marker of excessive daytime sleepiness.
This information can further be useful as you consider treatment options. For example, mild to moderate sleep apnea may be treated with continuous positive airway pressure (CPAP) as well as with oral appliances.
Positional therapy and other interventions may also be reasonable. Moreover, surgical treatments may be more effective at curing the condition in people with less severe sleep apnea.
There is some controversy regarding people who have a milder degree of sleep apnea. Along this spectrum may be pre-menopausal women (who are protected by the hormones estrogen and progesterone) or people of normal body weight who, rather than having overt sleep apnea, may instead have upper airway resistance syndrome (UARS).
It should additionally be noted that children may have sleep apnea diagnosed at a far lower AHI. Typically, the AHI is thought to be abnormal when it is greater than 1 (though this threshold was previously 2). This is complicated by developmental changes that occur in puberty.
Adolescents who have already gone through their major growth spurt may be best assessed using the adult classification. This assessment and determination is best made based on the clinical judgment of your child’s sleep specialist.
The AHI can also be useful to monitor your response to continuous positive airway pressure (CPAP) therapy. The goal is to be in the normal range, with fewer than 5 events per hour, but a lower number is better. It is often possible to optimize the settings to get the AHI down to 1 or 2.
If you have further questions about what the AHI means to you, speak with your doctor about the test results and the best treatment options to address your needs.
Updated 1st July 2017
Poor sleep may make us more likely to eat more and gain weight, according to preliminary research results.
Swedish scientists say poor sleep quality and fewer hours in bed can stimulate production of a hormone that makes us feel hungry.
They say it can also affect the way the body generates energy from food.
Modern Living: An increasing number of people are encountering sleep problems in our modern, 24/7 world. A number of studies have focused on how sleep loss can affect the body's ability to metabolize energy.
Christian Benedict from Uppsala University, who led the study, says the underlying cause of increased obesity risk from sleep disruption remains unclear, although it could be caused by changes in appetite, metabolism, motivationm physical activity, or a combination of factors.
He and his group have made a number of studies into the effect on energy metabolism caused by sleep loss. "Following sleep loss, normal-weight men prefer larger food portions, seek more calories, exhibit signs of increased food-related impulsivity, experience more pleasure from food, and expend less energy," he tells us.
Hunger Hormones: The latest findings, presented at the European Congress of Endocrinology in Lisbon, suggest that sleep loss seems to favour hormones that make us feel hungry.
"Our studies also indicate that sleep loss shifts the hormonal balance from hormones that promote fullness (satiety), such as the intestinal hormone glucagon-like peptide 1, to those that promote hunger, such as the stomach hormone ghrelin," says Christian Benedict.
Sleep restriction also increased levels of endocannabinoids, which are also linked to appetite, the findings suggest.
The researchers say that sleep loss also affects the balance of gut bacteria, which has been widely implicated as key for maintaining how our bodies process food into energy.
Other Health Factors: According to Mr Benedict: "My studies suggest that sleep represents an important pillar of metabolic health, including weight maintenance.
"However, it must be borne in mind that our health depends on an interplay of a variety of modifiable factors (e.g. exercise, diet, regular health checks) and non-modifiable factors (e.g. your genes), and not only sleep. In other words, sleeping about 7 hours, as recommended by sleep experts, won’t benefit your health if your lifestyle is otherwise a mess."
The study results should be treated with caution as they have yet to be published in a peer-reviewed journal.
Updated 28th June 2017
Many studies have explored the effects of light on the circadian rhythms of plants and animals, including humans. But few have looked at the direct effects of light on sleep.
Researchers at the California Institute of Technology set out to determine how and why light directly affects sleep. Scientists wanted to know why darkness is soporific, and why brightness can disrupt deep sleep. Testing in Caltech labs revealed a light-sensitive neural protein key in maintaining the proper balance between wakefulness and sleep.
“Researchers had previously identified the photoreceptors in the eye that are required for the direct effect of light on wakefulness and sleep,” said researcher David Prober, a professor of biology at Caltech, but we wanted to know how the brain uses this visual information to affect sleep.”
In the lab, researchers tagged the brain protein prokineticin 2, or Prok2, with bioluminescent markers in zebrafish models. Zebrafish follow a diurnal sleep-wake pattern similar to humans. They’re also translucent, making it easy to monitor neural activity.
Scientists engineered several zebrafish to over-express the Prok2 protein. The fish with an excess of Prok2 were more likely to fall asleep during the day and wake up at night. These effects were dependent on external light, not circadian rhythm.
Zebrafish with mutated Prok2 receptors showed the opposite effects. Their sleep-wake patterns were less influenced by light.
“Though diurnal animals such as zebrafish spend most of their time asleep at night and awake during the day, they also take naps during the day and occasionally wake up at night, similar to many humans,” Prober said. “Our study’s results suggest that levels of Prok2 play a critical role in setting the correct balance between sleep and wakefulness during both the day and the night.”
In follow up tests, researchers found Prok2 influences other proteins important to sleep patterns — including the protein galanin, which is active in a sleep-promoting brian region called the anterior hypothalamus.
Light and darkness proved less disruptive to the sleep patterns zebrafish that were engineered to over-express Prok2 but under-express galanin.
Prober and his colleagues shared the results of their experiments in the journal Neuron.
Updated June 27, 2017
Stress during the workday can lead to overeating and unhealthy food choices at dinnertime, but there could be a buffer to this harmful pattern. A good night’s sleep can serve as a protecting factor between job stress and unhealthy eating in the evening, indicates a new study co-authored by a Michigan State University scholar.
The study, published online in the Journal of Applied Psychology, is one of the first to investigate how psychological experiences at work shape eating behaviors. “We found that employees who have a stressful workday tend to bring their negative feelings from the workplace to the dinner table, as manifested in eating more than usual and opting for more junk food instead of healthy food,” said Chu-Hsiang “Daisy” Chang, MSU associate professor of psychology and study co-author.
“However, another key finding showed how sleep helped people deal with their stressful eating after work,” she added. “When workers slept better the night before, they tended to eat better when they experienced stress the next day.” The research involved two studies of 235 total workers in China. One study dealt with information-technology employees who regularly experienced high workload and felt there was never enough time in the workday.
The second study involved call-center workers who often got stressed from having to deal with rude and demanding customers. In both cases, workday stress was linked to employees’ negative mood while on the job, which in turn was linked to unhealthy eating in the evening, said Yihao Liu, co-author and assistant professor at the University of Illinois.
The study proposed two potential explanations, Liu said. “First, eating is sometimes used as an activity to relieve and regulate one's negative mood, because individuals instinctually avoid aversive feelings and approach desire feelings,” he said. “Second, unhealthy eating can also be a consequence of diminished self-control. When feeling stressed out by work, individuals usually experience inadequacy in exerting effective control over their cognitions and behaviors to be aligned with personal goals and social norms.”
Chang said the finding that sleep protects against unhealthy eating following workday stress shows how the health behaviors are related. “A good night's sleep can make workers replenished and feel vigorous again, which may make them better able to deal with stress at work the next day and less vulnerable to unhealthy eating,” she said. To address the problem, companies should emphasize the importance of health management for their employees and consider sleep-awareness training and flexible scheduling.
Companies should also reconsider the value of food-related job perks, which have become very common. “Food-related perks may only serve as temporary mood-altering remedies for stressed employees,” Chang said, “and failure to address the sources of the work stress may have potential long-term detrimental effects on employee health.” The paper is titled “Eating your feelings? Testing a model of employees’ work-related stressors, sleep quality and unhealthy eating.”
Updated June 26 2017
Preliminary data from two studies suggest that mild-to-moderate obstructive sleep apnea is associated with an increased risk of developing hypertension and diabetes.
“We found that even mild sleep apnea was strongly associated with increased risk of developing hypertension by 4 times compared to individuals without sleep apnea,” says principal investigator and lead author Alexandros N. Vgontzas, MD, professor in the Department of Psychiatry at Pennsylvania State University College of Medicine, in a release. “Similarly, moderate sleep apnea was associated with increased risk of developing diabetes by almost 3 times compared to individuals without sleep apnea.”
Results also show that these associations were strongest in young and middle-aged adults.
“In young and middle-aged adults, our findings suggest that early detection and treatment of mild-to-moderate sleep apnea is warranted in order to prevent future cardiometabolic disease,” says lead author and postdoctoral scholar Yun Li, MD. “Given the stronger association of sleep apnea with metabolic abnormalities in this age group, emphasis should be placed on yearly monitoring of indices of metabolic symptoms and lifestyle interventions, such as weight control, healthy diet, regular exercise, and stress management.”
While previous research has established that severe sleep apnea increases the risk of hypertension and diabetes, data regarding mild-to-moderate sleep apnea were unclear.
Both studies involved the Penn State Adult Cohort, a random general population sample of 1,741 adults. Participants completed a detailed medical history interview at baseline and were evaluated in a sleep center during an overnight sleep study. Those without hypertension or diabetes at baseline were followed up after 10 years.
Updated June 8th 2017
Trouble sleeping may take a bigger toll on women than on men, a new study from Australia finds.
Women in the study were more likely than men to have sleep disorders that made them feel tired during the day, the researchers found. And women were also more likely to have trouble with memory and concentration due to sleepiness.
"We found that females were more likely to have sleeping disorders associated with daytime sleepiness," study co-author Dr. John Malouf, the founder of the SleepGP sleep clinic in Coolangatta, Australia, said in a statement. "Females were also likely to feel more affected by the burden of their symptoms.
In the study, which was published in May in the Journal of Clinical Sleep Medicine, the researchers looked at data on nearly 750 adults in Australia who had sought medical care for sleep problems between April 2013 and January 2015. At the time, the people filled out questionnaires about their sleep and overall health.
For example, the questionnaires asked if the people ever had trouble falling asleep and if they felt excessively tired or sleepy during the day. One question asked if the people had trouble concentrating during the day because of sleepiness. In addition, the researchers wanted to know if the participants or their partners snored.
One-third of all people in the study said that they had trouble falling asleep at night, though this was more common among the women than the men. Nearly half of the women reported problems falling asleep compared with just 27 percent of men.
The women in the study also reported more problems during the day as a result of their sleep problems at night.
For example, nearly half of the women in the study, 49 percent, said they had sleep problems that caused daytime sleepiness, while 37 percent of the men in the study said the same. The researchers also found that 77 percent of the women felt excessively sleepy or tired during the day, compared with 66 percent of the men.
Daytime sleepiness had a significant effect on the women's ability to concentrate during the day; 89 percent of the women said they had trouble concentrating because they were tired, compared with 74 percent of men. And 80 percent of women said that being sleepy led to memory problems, compared with 58 percent of men, the study found.
The reasons behind these differences between the sexes are unclear, and more research is needed to explore possible reasons, the researchers said. However, previous studies have suggested that hormonal factors as well as anatomical and physiological differences between men and women may play a role, the study said.
Women in the study also seemed to be more affected by their partners' snoring, the research said. Snoring men were more likely to keep their partners awake than snoring women were.
This was particularly apparent when the researchers asked the participants if their snoring had ever forced their partners out of the bedroom. The scientists found that 63 percent of the men who said their snoring kept their partners awake also said that the snoring forced their partners from the room; 54 percent of the women who said their snoring kept their partners awake also said that the snoring forced their partners out of the room.
Though the reasons behind the findings on snoring are unclear, it is possible that women are simply more sensitive to their partners' snoring and men have a higher tolerance for their partners' snoring, the researchers said.
Updated June 4th 2017
Your brain starts to eat itself if it hasn't had enough sleep, according to a new study.
Researchers studied lab mice, and found that 'clean-up' cells were more active in their brains when they were sleep-deprived.
The cells, known as astrocytes, act like mini Hoovers in the brain, sweeping up cells as the brain's connections become weak and break apart.
'We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,' said author Michele Bellesi.
According to the research team at Italy's Marche Polytechnic University, the seemingly alarming process is actually a positive thing.
The cells, known as astrocytes, act like mini Hoovers in the brain, sweeping up cells as the brain's connections become weak and break apart, according to Italian researchers
'Our synpases are like old pieces of furniture,' Bellesi said. 'and so they probably need more attention and cleaning.'
But he added that sleep-deprived brains showed ominous signs of activity that leads to Alzheimer's.
In sleep-deprived mice, brain cells called microglials were more active.
'We already know that sustained microglial activation has been observed in Alzheimer's and other forms of neurodegeneration,' Michele said.
The news comes on the heels of research that showed having too little sleep could put people at risk from heart disease.
The study found that having less than six hours sleep a night was associated with a higher risk of death in people with metabolic syndrome – a combination of diabetes, high blood pressure and obesity.
Researchers said the effect was particularly strong in those with elevated blood pressure or poor glucose metabolism.
People with a common cluster of risk factors for heart disease and diabetes were around twice as likely to die of heart disease or stroke as people without the same set of risk factors if they failed to get more than six hours of sleep, according to the study published in the Journal of the American Heart Association.
For those who got more sleep, the risk of death was more modest.
The study is the first to measure sleep duration in a laboratory rather than relying on patient reports, and the first to examine the impact of sleep duration on the risk of death in those with a common cluster of heart disease risk factors.
The researchers randomly selected 1,344 adults with an average age of 49 who agreed to spend one night in a sleep laboratory.
Based on their test results, 39.2 per cent of the participants were found to have at least three of the risk factors, that when clustered together are known as the metabolic syndrome.
For the study, the cluster included body mass index (BMI) higher than 30 - the standard definition of being obese, as well as elevated total cholesterol, blood pressure, fasting blood sugar and triglyceride levels.
During an average follow-up of 16.6 years, 22 per cent of the participants died.
Compared to people without the same cluster of risk factors, those with metabolic syndrome who clocked more than six hours of sleep time in the lab were about 1.49 times more likely to die of stroke during the follow-up period.
But those who slept less than six hours in the lab were about 2.1 times more likely to die of heart disease or stroke.
Updated May 27th 2017
A new study suggests that men and women are affected differently by sleep disorders.
Results show that women are more likely than men to have more severe symptoms of depression, trouble sleeping at night, and excessive daytime sleepiness. Women also have a higher degree of difficulty concentrating and remembering things due to sleepiness or tiredness. In contrast, male snoring was more likely than female snoring to force bed partners to sleep in different rooms.
"We found that females were more likely to have sleeping disorders associated with daytime sleepiness," said co-author Dr. John Malouf, founder of SleepGP sleep clinic in Coolangatta, Queensland, Australia. "Females were also likely to feel more affected by the burden of their symptoms."
The main purpose of the study was to understand the differences in functional status between the sexes when they present to primary care providers with sleep problems.
"What was surprising about the results was that while men and women tended to present at a similar age, their symptoms and the effect on their lives differed markedly," said lead author Allegra Boccabella, research associate at SleepGP clinic. "We didn't expect there to be differences across the board in terms of the different aspects of people's lives."
Study results are published in the May 15 issue of the Journal of Clinical Sleep Medicine.
Boccabella and Malouf conducted a retrospective clinical audit of 744 patients who received sleep-related health care from 7 private general practices in Australia between April 2013 and January 2015. Patients completed a variety of sleep-related questionnaires, including the Epworth Sleepiness Scale (ESS), the Snoring Severity Scale (SSS), and the Functional Outcomes of Sleep Questionnaire 10.
According to the authors, understanding how the symptoms reported by women differ from those of men can help medical professionals manage sleep disorders more holistically.
"If we can identify the ways that their lives are affected, we can help produce better outcomes for the patient," said Boccabella.
American Academy of Sleep Medicine.
Updated May 26th 2017
Children who are known to frequently snore may be suffering from some health issue including tonsil enlargement, septum deviation, adenoids.
Different health organizations and their researches have stated various reasons which lead to snoring. According to the ENT experts, whenever our brain undergoes imbalance, it causes snoring to bring out regularity in brain functioning as snoring changes the breathing pattern. Respiratory problems, such as infection can also be one of the many reasons behind snoring according to the National Sleep Foundation at the United States.
According to a new study published in the Laryngology and Otology, one must keep a check how frequent the snoring in their child is to catch health issues before they get huge. In this study carried out, a research on a thousand children was conducted for six years period. The research concluded that the children who breathed heavily, from mouth or who had regular frequent snoring issues were more prone to health problems like cognitive dysfunctioning, behavioral problems and were highly vulnerable to develop ADHD symptoms.
It is highly recommended that monitoring of the snoring is regularly carried to know the nature of it, and if it is found to be frequent enough, medical help is advisable to prevent multiple health issues which this prolonged snoring syndrome makes children vulnerable to. Evaluating sleep accurately can help in curing this, like if the child sweats while sleeping; it is because it is unable to breathe smoothly which leads to struggle in breathing thus causing sweat.
The remedies to this include an elevated head support while sleeping, preventing child’s contact with objects like pets and soft toys since these objects may cause allergic reaction and respiratory concerns in child’s body and most importantly a regular check on the snoring frequency and regularity.
Updated May 21 2017
New research shows that a recently discovered mechanism that removes waste products from the brain is mainly active during sleep. This revelation could transform scientific understanding of what sleep is for, and how it works and offers new directions for brain disease treatments.
The team, from University of Rochester Medical Center (URMC), write about their findings in the latest online issue of Science.
Lead author Dr. Maiken Nedergaard, co-director of URMC's Center for Translational Neuromedicine, says:
"This study shows that the brain has different functional states when asleep and when awake. In fact, the restorative nature of sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness."
The purpose of sleep has puzzled scientists and philosophers for millennia. While more recent research shows sleep can help with storing and consolidating memory, this alone does not balance the huge disadvantages it poses.
From a survival point of view, sleep is rife with risk - all creatures are at their most vulnerable during sleep, especially when predators are around. But if sleep has no biological function, then could it just be an evolutionary glitch?
In 2012, Nedergaard and colleagues reported that by using new imaging technology on mice, they had discovered a previously unrecognized system that drains waste from the brain.
In a paper published in Science Translational Medicine they dubbed this the "glymphatic system," because it acts like the body's lymphatic system but is managed by brain cells known as glial cells.
The glymphatic system clears away toxins or waste products that could be responsible for brain diseases, such as Alzheimer's disease and other neurological disorders.
In this study, the team conducted a series of new experiments on mice and found that the glymphatic system is nearly 10 times more active during sleep. They also noted that the sleeping brain removes significantly more amounts of one toxic protein, amyloid-beta, which is implicated in Alzheimer's disease.
Dr. Nedergaard says:
"The brain only has limited energy at its disposal and it appears that it must [choose] between two different functional states - awake and aware or asleep and cleaning up. You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can't really do both at the same time."
The team also found that during sleep, the brain even undergoes physical changes that allows the system to work faster. Brain cells shrink by 60%, increasing the space between them so the toxins can be flushed away more effectively.
Another discovery was that noradrenaline, a brain chemical that is released in bursts to keep the brain alert in response to fear and other stimuli, is less active during sleep, leading the team to suggest that the neurotransmitter may control the expansion and shrinking of brain cells during sleep-wake cycles.
Nedergaard says their findings are important for treating "dirty brain" diseases, such as Alzheimer's:
"Understanding precisely how and when the brain activates the glymphatic system and clears waste is a critical first step in efforts to potentially modulate this system and make it work more efficiently."
Funds from the National Institute of Neurological Disorders and Stroke helped finance the study.
Written by Catharine Paddock PhD
Updated May 20 2017
