By NICHOLAS BAKALAR Insomnia may be linked to an increased risk of heart failure, according to a large new study, and the more insomnia symptoms, the greater the risk. The study, published last week in The European Heart Journal, used questionnaires to gather data on difficulty falling asleep, difficulty staying asleep, and waking unrefreshed among more than 54,000 Norwegian adults in a population-wide health survey. All were free of heart disease at the start of the study; there were 1,412 cases of heart failure over an average of 11 years of follow-up. After controlling for numerous health, behavioral and demographic factors, the researchers found that having one symptom of insomnia was associated with a 17 percent increase in the risk of developing heart failure. Having two symptoms increased the chances by 92 percent, and having all three nearly tripled the risk. Insomnia was a risk independent of other cardiovascular risks, and the authors suggest that chronic insomnia leads to higher blood pressure and higher heart rate, known risk factors for heart failure. “We cannot claim that insomnia is causing heart failure,” said the lead author, Lars E. Laugsand, a postdoctoral fellow at the Norwegian University of Science and Technology. “But observational studies are all going more or less in the same direction — showing that insomnia may play a role in heart problems.” Copyright 2013 The New York Times Company

Keyword: Sleep
Link ID: 17895 - Posted: 03.12.2013

By David Robson, The dreams of Mary Shelley, author of “Frankenstein,” involved a pale student kneeling beside a corpse that was jerking back to life. Paul McCartney’s contained the melody of “Yesterday,” while director James Cameron’s inspired the “Terminator” films. With their eerie mixture of the familiar and the bizarre, it is easy to look for meaning in these nightly wanderings. But why do our brains take these journeys, and why do they contain such outlandish twists and turns? Unfortunately for armchair psychoanalysts, Sigmund Freud’s attempts to interpret dreams remain hotly disputed. Nevertheless, neuroscientists and psychologists have recently made big strides in understanding the way the brain builds our dreams and the factors that shape those curious stories. Along the way, they have found startling hints that our use of technology may be permanently changing the nature of this fundamental human experience. Anyone who has ever awakened feeling amazed by a dream, only to forget its contents before reaching the shower will understand the difficulties of studying such an ephemeral state of mind. Some of the best attempts to catalogue dream features either asked participants to jot them down as soon as they woke up or had volunteers sleep in a lab where they were awakened and immediately questioned at intervals in the night. © 1996-2013 The Washington Post

Keyword: Sleep
Link ID: 17894 - Posted: 03.12.2013

by Elizabeth Norton The prospect of undergoing surgery while not fully "under" may sound like the stuff of horror movies. But one patient in a thousand remembers moments of awareness while under general anesthesia, physicians estimate. The memories are sometimes neutral images or sounds of the operating room, but occasionally patients report being fully aware of pain, terror, and immobility. Though surgeons scrupulously monitor vital signs such as pulse and blood pressure, anesthesiologists have no clear signal of whether the patient is conscious. But a new study finds that the brain may produce an early-warning signal that consciousness is returning—one that's detectable by electroencephalography (EEG), the recording of neural activity via electrodes on the skull. "We've known since the 1930s that brain activity changes dramatically with increasing doses of anesthetic," says the study's corresponding author, anesthesiologist Patrick Purdon of Massachusetts General Hospital in Boston. "But monitoring a patient's brain with EEG has never become routine practice." Beginning in the 1990s, some anesthesiologists began using an approach called the bispectral (BIS) index, in which readings from a single electrode are connected to a device that calculates, and displays, a single number indicating where the patient's brain activity falls on a scale of 100 (fully conscious) to zero (a "flatline" EEG). Anything between 40 and 60 is considered the target range for unconsciousness. But this index and other similar ones are only indirect measurements, Purdon explains. In 2011, a team led by anesthesiologist Michael Avidan at the Washington University School of Medicine in St. Louis, Missouri, found that monitoring with the BIS index was slightly less successful at preventing awareness during surgery than the nonbrain-based method of measuring exhaled anesthesia in the patient's breath. Of the 2861 patients monitored with the BIS index, seven had memories of the surgery, whereas only two of 2852 patients whose breath was analyzed remembered anything. © 2010 American Association for the Advancement of Science.

Keyword: Sleep; Aggression
Link ID: 17870 - Posted: 03.05.2013

By David Brown, Hey, you, yawning in your cubicle at 2 in the afternoon. Your genes feel it, too. A new study, paid for by the U.S. Air Force but relevant for anyone with a small child, a large prostate or a lot on the mind, is helping illuminate what’s happening at the genetic level when we don’t get enough sleep. It turns out that chronic sleep deprivation — in this experiment, less than six hours a night for a week — changes the activity of about 700 genes, which is roughly 3 percent of all we carry. About one-third of the affected genes are ramped up when we go with insufficient sleep night after night. The other two-thirds are partially suppressed. Hundreds of “circadian genes” whose activity rises and falls each day abruptly lose their rhythm. Among the genes disturbed by sleep deprivation are ones involved in metabolism, immunity, inflammation, hormone response, the expression of other genes and the organization of material called chromatin on chromosomes. These changes may help explain how inadequate sleep alters attention and thinking and raises the risk for illnesses such as diabetes and coronary heart disease. “The findings will identify some of the pathways linking insufficient sleep and negative health outcomes,” said Derk-Jan Dijk, a physiologist at the University of Surrey in England, who led the study. “But how these things ultimately lead to obesity or diabetes is an unanswered question at this moment in time.” © 1996-2013 The Washington Post

Keyword: Sleep; Aggression
Link ID: 17869 - Posted: 03.05.2013

Steve Connor Physical exhaustion can occur when the brain – as well as the muscles – grows tired according to a study that sheds fresh light on the role played by the mind in determining endurance levels. Scientists have found that a key neurotransmitter in the brain, which controls signalling between nerve cells, can determine whether someone feels exhausted following physical exercise or after taking anti-depressant drugs such as Prozac. Although levels of serotonin rise during exercise, which provides a psychological boost and “feel-good” factor, it can also result in a widespread central fatigue that ultimately leads to someone feeling exhausted and unable to carry on, scientists found. Researchers led by Professor Jean-Francois Perrier of the University of Copenhagen found that while serotonin helps to keep people going during the early stage of vigorous exercise, a build-up of the neurotransmitter in the brain can have the opposite effect by causing “central fatigue” of the nervous system even when the muscles are still able to carry on. “We can now see it is actually a surplus of serotonin that triggers a braking mechanism in the brain. In other words, serotonin functions as an accelerator but also as a brake when the strain becomes excessive,” said Professor Perrier, whose study is published in the Proceedings of the National Academy of Sciences. © independent.co.uk

Keyword: Sleep
Link ID: 17868 - Posted: 03.05.2013

By James Gallagher Health and science reporter, BBC News A run of poor sleep can have a dramatic effect on the internal workings of the human body, say UK researchers. The activity of hundreds of genes was altered when people's sleep was cut to less than six hours a day for a week. Writing in the journal Proceedings of the National Academy of Sciences, the researchers said the results helped explain how poor sleep damaged health. Heart disease, diabetes, obesity and poor brain function have all been linked to substandard sleep. What missing hours in bed actually does to alter health, however, is unknown. So researchers at the University of Surrey analysed the blood of 26 people after they had had plenty of sleep, up to 10 hours each night for a week, and compared the results with samples after a week of fewer than six hours a night. More than 700 genes were altered by the shift. Each contains the instructions for building a protein, so those that became more active produced more proteins - changing the chemistry of the body. Meanwhile the natural body clock was disturbed - some genes naturally wax and wane in activity through the day, but this effect was dulled by sleep deprivation. Prof Colin Smith, from the University of Surrey, told the BBC: "There was quite a dramatic change in activity in many different kinds of genes." Areas such as the immune system and how the body responds to damage and stress were affected. BBC © 2013

Keyword: Sleep
Link ID: 17848 - Posted: 02.26.2013

An international team of biologists has successfully identified some of the brain chemicals that may help clarify some unanswered questions about how humans sleep. The research - conducted by the University of California, Los Angeles (UCLA) and the University of Toronto - focused on seals and the chemicals found in their brain, as they are able to sleep with half their brain at a time. Professor John Peever of the University of Toronto said: "Seals do something biologically amazing - they sleep with half their brain at a time. The left side of their brain can sleep while the right side stays awake. Seals sleep this way while they're in water, but they sleep like humans while on land. Our research may explain how this unique biological phenomenon happens." The study's first author, PhD student Jennifer Lapierre, measured how the brain chemicals change while the seals are asleep and awake. She found that acetylcholine - an important brain chemical - was at low levels on the sleeping side of the brain, but high levels on the waking side. This discovery suggests that acetylcholine may be responsible for brain alertness. They also discovered - to their surprise - that the chemical serotonin was present in both sides of the brain whether the seal was awake or asleep. It was previously thought that serotonin caused brain arousal. Researchers hope that the discovery of the chemicals may make a breakthrough in understanding and curing sleeping disorders. The study's senior author, Jerome Siegel from UCLA's Brain Research Institute added: "Understanding which brain chemicals function to keep us awake or asleep is a major scientific advance. It could help solve the mystery of how and why we sleep." © independent.co.uk

Keyword: Sleep
Link ID: 17840 - Posted: 02.23.2013

By Tina Hesman Saey Like the sun, insulin levels rise and fall in a daily rhythm. Disrupting that cycle may contribute to obesity and diabetes, a new study suggests. Many body systems follow a daily clock known as a circadian rhythm. Body temperature, blood pressure and the release of many hormones are on circadian timers. But until now, no one had shown that insulin — a hormone that helps control how the body uses sugars for energy — also has a daily cycle. Working with mice, researchers at Vanderbilt University in Nashville have found that rodents are more sensitive to insulin’s effects at certain times of day. Disrupting the animals’ circadian timers interferes with the hormone’s daily rise and fall and makes mice prone to obesity. If the findings hold up in humans, they could help explain why people who work night shifts tend to be overweight and suffer health problems. The discovery may also tie the obesity epidemic in part to staying up late and eating at the wrong time. Many people had thought that it was best for the body to maintain insulin at a relatively constant level, says Carl Johnson, a circadian biologist who led the new study. “But that’s not how organisms have adapted,” he says. Since the environment cycles through light and dark, body processes often coordinate with that rhythm. To uncover insulin’s natural rhythm, Johnson and his colleagues performed an “insulin clamp” procedure on mice. The clamp infuses glucose or insulin around the clock into mice that are moving freely in their cages. Measuring how much insulin or glucose the mice need to maintain constant blood sugar levels tells the researchers how responsive the animals are to the hormone at any given time of day. © Society for Science & the Public 2000 - 2013

Keyword: Biological Rhythms; Aggression
Link ID: 17831 - Posted: 02.23.2013

By Laura Hambleton, Winter often brings the flu, coughs, ski injuries and shoveling strains. Add to these ailments a more deadly one: heart attacks. A recent study has found that more fatal heart attacks and strokes occur during the winter than at other times of the year. And it doesn’t seem to matter if the winter is occurring in the warmer climes of Southern California or the frostier ones of Boston. After sifting through about 1.7 million death certificates filed between 2005 and 2008, cardiologists Bryan Schwartz of the University of New Mexico and Robert A. Kloner of the Heart Institute at the Good Samaritan Hospital in Los Angeles found a 26 to 36 percent greater death rate for heart attacks in winter than summer “despite different locations and climates,” Kloner says. The worst months are December, January, February and the beginning of March. The doctors analyzed the cause of death for people in Texas, Arizona, Georgia, Los Angeles, Washington state, Pennsylvania and Massachusetts. Of those who died of heart disease, the winter weather pattern was clear. In Los Angeles, for example, there were about 70 deaths per day from cardiac disease, Schwartz said. “In the summer, L.A. had an average circulatory death rate of about . . . 55 deaths per day.” The research uncovered patterns in cardiac deaths from “seven different climate patterns,” according to the study, and “death rates at all sites clustered closely together and no one site was statistically different from any other site.” An abstract of the study was published in the American Heart Association journal Circulation. © 1996-2013 The Washington Post

Keyword: Biological Rhythms; Aggression
Link ID: 17763 - Posted: 02.05.2013

By Morgen Peck Co-sleeping, the practice of sharing a bed with your baby, has a controversial place in modern society. Proponents argue that it increases the parent-child bond, whereas detractors worry about safety. Now an anthropological study adds a new finding to the debate: fathers who sleep next to their babies tend to have significantly lower levels of testosterone than those who sleep in a different room. Lee Gettler, an anthropologist at the University of Notre Dame, compared Filipino men's testosterone levels before having a child and again four years later. Men who reported sleeping on the same surface as their child experienced a steep decline in nighttime testosterone levels not seen in men who slept in another room, according to the paper published in September 2012 in PLOS One. Studies on women have shown that mothers who sleep with their children pass in and out of sleep. The same disruptions in men could possibly decrease testosterone production, Gettler and his co-authors write. Previous work in the same population showed that fathers who fully throw themselves into caring for their children are more likely to have low testosterone, suggesting that hormonal fluctuations may support men in being good fathers. “Lower testosterone might orient men more toward the needs of the partner and children and away from risky behavior and competition with other males—which could conflict with investments in parenting,” Gettler says. © 2013 Scientific American

Keyword: Sexual Behavior; Aggression
Link ID: 17748 - Posted: 02.04.2013

By Stephani Sutherland If you have trouble sleeping, laptop or tablet use at bedtime might be to blame, new research suggests. Mariana Figueiro of the Lighting Research Center at Rensselaer Polytechnic Institute and her team showed that two hours of iPad use at maximum brightness was enough to suppress people's normal nighttime release of melatonin, a key hormone in the body's clock, or circadian system. Melatonin tells your body that it is night, helping to make you sleepy. If you delay that signal, Figueiro says, you could delay sleep. Other research indicates that “if you do that chronically, for many years, it can lead to disruption of the circadian system,” sometimes with serious health consequences, she explains. The dose of light is important, Figueiro says; the brightness and exposure time, as well as the wavelength, determine whether it affects melatonin. Light in the blue-and-white range emitted by today's tablets can do the trick—as can laptops and desktop computers, which emit even more of the disrupting light but are usually positioned farther from the eyes, which ameliorates the light's effects. The team designed light-detector goggles and had subjects wear them during late-evening tablet use. The light dose measurements from the goggles correlated with hampered melatonin production. On the bright side, a morning shot of screen time could be used as light therapy for seasonal affective disorder and other light-based problems. Figueiro hopes manufacturers will “get creative” with tomorrow's tablets, making them more “circadian friendly,” perhaps even switching to white text on a black screen at night to minimize the light dose. Until then, do your sleep schedule a favor and turn down the brightness of your glowing screens before bed—or switch back to good old-fashioned books. © 2013 Scientific American

Keyword: Biological Rhythms; Aggression
Link ID: 17743 - Posted: 02.02.2013

When you eat could play an important role in weight loss, a new study suggests. Researchers looked at the role of meal timing in 420 men and women in southeast Spain participating in a 20-week weight-loss treatment following several studies in animals showing a relationship between the timing of feeding and weight regulation. Lunch was the main meal among the Mediterranean population studied.Lunch was the main meal among the Mediterranean population studied. (Eric Gaillard/Reuters) "Our results indicate that late eaters displayed a slower weight-loss rate and lost significantly less weight than early eaters, suggesting that the timing of large meals could be an important factor in a weight loss program," Frank Scheer, director of the medical chronobiology program at Brigham and Women's Hospital in Boston, said in a release. Of the participants, 51 per cent were early eaters who ate their main meal, lunch, before 3 p.m. The other 49 per cent had lunch after three. The researchers found energy and nutrient intake, estimates of calories burned, appetite hormones and hours of sleep were similar between both groups. "Nevertheless, late eaters were more evening types, had less energetic breakfasts and skipped breakfast more frequently than early eaters," Scheer and his co-authors wrote in Tuesday's issue of the International Journal of Obesity. They suggested that new weight loss strategies should incorporate the timing of food as well as the classic look at calorie intake and distribution of carbohydrates, fats and protein. © CBC 2013

Keyword: Obesity; Aggression
Link ID: 17728 - Posted: 01.29.2013

Mo Costandi Deterioration of a specific brain region impairs sleep quality as people age, leading to poorer memory retention, according to research published today in Nature Neuroscience1. Ageing is associated with the gradual loss of brain cells, sleep disturbances and declining memory function, but how these factors are related to each other has been unclear. Neuroscientist Bryce Mander at the University of California, Berkeley, and his colleagues recruited 33 healthy adults — 18 around the age of 20, and 15 ranging from late sixties to late seventies — all with normal mental function, and asked them to memorize a list of word pairs. The participants were asked to recall some of the word pairs ten minutes later, then left to sleep overnight while the researchers recorded the electrical activity of their brains. The next morning, volunteers were asked to recall selected words from the list again while having their brains scanned. In keeping with earlier studies, the older adults performed less well than the younger ones on the memory test, and showed significant reductions in the slow brain waves associated with deep sleep. The extent of deep-sleep disruption was related to the degree of memory impairment, with those exhibiting the least slow-wave activity performing the worst. These differences were also associated with a reduction of grey matter in a part of the brain called the medial prefrontal cortex. © 2013 Nature Publishing Group,

Keyword: Sleep; Aggression
Link ID: 17723 - Posted: 01.28.2013

By SABRINA TAVERNISE WASHINGTON — For two decades, millions of Americans have taken Ambien to help them sleep at night. But for years, the Food and Drug Administration has gotten complaints that people felt drowsy the morning after taking the medicine or its successors, and sometimes got into car accidents. On Thursday the agency said that women should be taking half as much, after laboratory studies and driving tests confirming the risks of drowsiness. The new recommendation applies to drugs containing the active ingredient zolpidem, by far the most widely used sleep aid. Using lower doses means less of the drug will remain in the blood in the morning hours, and will reduce the risk that people who use it will be impaired while driving. Sleeping pills have boomed in popularity with the increasingly frantic pace of modern American life. According to IMS, a health care information and technology company, about 60 million prescriptions were dispensed in 2011, up about 20 percent since 2006. About 40 million were for products containing zolpidem. The agency’s announcement was focused on women because they take longer to metabolize the drug than men. An estimated 10 percent to 15 percent of women will have a level of zolpidem in their blood that could impair driving eight hours after taking the pill, while only about 3 percent of men do, said Dr. Robert Temple, an official in the agency’s Center for Drug Evaluation and Research. © 2013 The New York Times Company

Keyword: Sleep; Aggression
Link ID: 17675 - Posted: 01.12.2013

By Susan Milius Male European blackbirds monitored in a lab under simulated city lighting started secreting increased levels of testosterone and growing their sexual organs up to a month earlier in the spring than birds kept in country-style darkness, Davide Dominoni of the Max Planck Institute for Ornithology in Radolfzell, Germany, reported January 6 at the annual meeting of the Society for Integrative and Comparative Biology. Dominoni’s colleagues have found that, outside the lab, male blackbirds flying around Munich undergo this growth surge about three weeks earlier than counterparts in a forest just 40 kilometers out of town. Beginning in December 2010, the researchers exposed captive blackbirds to night light levels typical of urban settings. They estimated those levels by outfitting free-flying blackbirds with light-sensitive devices and averaging the urban light exposure. A winter of lab night light sped up the males’ molting and boosted testosterone levels as well as organ development in spring. Continuing the night light treatment through the next winter left the males reproductively shut down in the spring of 2012. The lab night lights probably kept the birds’ seasonal reproductive clocks from resetting at the end of the first breeding season, Dominoni says. That second-year suppression may not be common in the real world, where birds fly around and experience more variety in night lighting, he says. But he sees the lab breeding shutdown as a sign of how big of an impact artificial light might have. © Society for Science & the Public 2000 - 2013

Keyword: Biological Rhythms; Aggression
Link ID: 17664 - Posted: 01.10.2013

By Laura Sanders Astronauts on a months-long mission to Mars and back will have more to contend with than boredom and a lack of gourmet cuisine: Disrupted sleep may be a serious side effect of extended space flight, potentially changing crew dynamics and affecting performance on high-pressure tasks. In an epic feat of playacting, a crew of six men lived for 520 days inside a hermetically sealed 550-cubic-meter capsule in Moscow. As the grueling experiment wore on, the crew drifted into torpor, moving less and sleeping more. Four men experienced sleep problems, scientists report online January 7 in the Proceedings of the National Academy of Sciences. Developed by the Russian Academy of Sciences, the “Mars 500” project was designed to test the feasibility of sending people on a journey to Mars and back. The simulation was realistic: The chamber was sealed, mission control was on standby 24 hours a day with built-in communications delays during parts of the mission, and the crew had specific jobs to do during transit and on a simulated landing on Mars. “If we at some point really want to go to Mars and we want to send humans, then we need to know how they will cope with this long period of confinement,” says study coauthor Mathias Basner, of the University of Pennsylvania’s Perelman School of Medicine in Philadelphia. Basner’s team was one of many that conducted studies on the six men during the long simulation. © Society for Science & the Public 2000 - 2013

Keyword: Sleep
Link ID: 17658 - Posted: 01.08.2013

By ANAHAD O'CONNOR A new study of driving behavior across the country found that slightly more than 4 percent of adults admit to having fallen asleep at the wheel. Certain people were particularly likely to report drowsiness while driving, including those who slept less than six hours daily and those who snored at night, a potential sign of a sleep disorder. Though only 4.2 percent of adults said they had actually fallen asleep while driving in the past 30 days, the researchers said they believed the true number was probably several times that, since people who doze or nod off for a moment at the wheel may not realize it at the time or recall it later on. Drowsy driving has a widespread impact on the nation’s highways, experts say. In 2009, an estimated 730 deadly motor vehicle accidents involved a driver who was either sleepy or dozing off, and an additional 30,000 crashes that were nonfatal involved a drowsy driver. Accidents involving sleepy drivers are more likely to be deadly or cause injuries, in part because people who fall asleep at the wheel either fail to hit their brakes or veer off the road before crashing. To get a sense of just how prevalent the phenomenon is, Anne G. Wheaton, an epidemiologist at the Centers for Disease Control and Prevention, led a study looking at 147,000 adults in 19 states and the District of Columbia. The subjects were asked detailed questions about their daily activities, including their driving, sleep and work habits. Dr. Wheaton and her colleagues found that men were more likely to report drowsy driving than women, and that the behavior increased with age. About 1.7 percent of adults between 18 and 44 admitted to it, compared to 5 percent or more of those age 65 or older. The findings were published in the latest issue of Morbidity and Mortality Weekly Report. Copyright 2013 The New York Times Company

Keyword: Sleep; Aggression
Link ID: 17651 - Posted: 01.05.2013

By ANAHAD O'CONNOR Chronic sleep loss has many downsides, among them weight gain, depression and irritability. But now scientists have found a new one: It also weakens your tolerance for pain. In recent studies, researchers have shown that losing sleep may disrupt the body’s pain signaling system, heightening sensitivity to painful stimuli. Though it is not clear why, one theory is that sleep loss increases inflammation throughout the body. Catching up on sleep if you are behind may reduce inflammation. Scientists believe this could have implications for people with chronic pain. It could also have an impact on the effects of painkillers, which appear to be blunted after chronic sleep loss. In one study published in the journal Sleep, scientists at the sleep disorders and research center at Henry Ford Hospital in Detroit recruited 18 healthy adults and split them into two groups. One was allowed to sleep for an average of nine hours, while the other averaged two fewer hours of sleep each night. To assess pain thresholds, the researchers measured how long the subjects were able to hold a finger to a source of radiant heat. After four nights, the group that was allowed to sleep the longest was able to withstand the painful stimuli much longer, by about 25 percent on average. Several studies in the past have had similar findings, including one in 2006 that showed that one night of cutting sleep in half could significantly reduce a person’s threshold for physical pain. Copyright 2012 The New York Times Company

Keyword: Sleep; Aggression
Link ID: 17612 - Posted: 12.18.2012

One in five U.S. adults shows signs of chronic sleep deprivation, and a shortage of sleep has been linked to health problems as different as diabetes and Alzheimer’s disease. Recent studies have found some interesting connections between illness and what is happening in our brains as we snooze. One in five U.S. adults shows signs of chronic sleep deprivation © 1996-2012 The Washington Post

Keyword: Sleep
Link ID: 17575 - Posted: 12.04.2012

By BENEDICT CAREY Subtle breathing problems during sleep may play a larger role in causing insomnia than the usual suspects, like stress and the need for a bathroom, a small study of poor sleepers suggests. The report, published in the current issue of the journal Sleep, found that chronic insomniacs woke an average of about 30 times a night, and that a brief respiratory problem — a drop in the volume of oxygen inhaled, due to a narrowed airway, for instance — preceded about 90 percent of those interruptions. None of the people had any idea they had breathing problems during sleep. The study is hardly conclusive, experts said, because it included only 20 people and had no control group of normal sleepers for comparison. But these experts said that it was worth following up, because it challenged the predominant theory of insomnia as a problem of “hyper-arousal,” in which the body idles on high psychologically and physiologically. Earlier studies have linked measures of hyper-arousal to delays in falling asleep and problems nodding off after interruptions. But the theory does not satisfactorily explain what prompts awakenings in the first place. The new study compared chronic insomniacs’ opinions about why they awoke at night with data from a sleep test monitoring breathing and brain waves — and does provide a possible explanation. “It is a striking finding that by no means can be discounted,” said Dr. Michael J. Sateia, a professor of psychiatry and sleep medicine at Dartmouth College’s school of medicine, who was not involved in the research. Still, he added, “we know arousal can in and of itself promote instability of the upper airway,” and it is not always clear which comes first. Copyright 2012 The New York Times Company

Keyword: Sleep
Link ID: 17574 - Posted: 12.04.2012