Chapter 14. Biological Rhythms, Sleep, and Dreaming

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Bill Chappell Jeffrey C. Hall, Michael Rosbash a and Michael W. Young are the joint winners of the 2017 Nobel Prize in Physiology or Medicine, winning for their discoveries about how internal clocks and biological rhythms govern human life. The three Americans won "for their discoveries of molecular mechanisms controlling the circadian rhythm" the Nobel Foundation says. From the Nobel Assembly at Karolinska Institutet, which announced the prize early Monday morning: "Using fruit flies as a model organism, this year's Nobel laureates isolated a gene that controls the normal daily biological rhythm. They showed that this gene encodes a protein that accumulates in the cell during the night, and is then degraded during the day. Subsequently, they identified additional protein components of this machinery, exposing the mechanism governing the self-sustaining clockwork inside the cell. We now recognize that biological clocks function by the same principles in cells of other multicellular organisms, including humans. "With exquisite precision, our inner clock adapts our physiology to the dramatically different phases of the day. The clock regulates critical functions such as behavior, hormone levels, sleep, body temperature and metabolism." Hall, 72, was born in New York and has worked at institutions from the University of Washington to the California Institute of Technology. For decades, he was on the faculty at Brandeis University in Waltham, west of Boston; more recently, he has been associated with the University of Maine. Rosbash, 73, was born in Kansas City, Mo., and studied at the Massachusetts Institute of Technology and at the University of Edinburgh in Scotland. Since 1974, he has been on faculty at Brandeis University in Waltham, Mass. Young, 68, was born in Miami, Fla., and earned his doctoral degree at the University of Texas in Austin. He then worked as a postdoctoral fellow at Stanford University in Palo Alto before joining the faculty at the Rockefeller University in 1978. © 2017 npr

Keyword: Biological Rhythms
Link ID: 24136 - Posted: 10.02.2017

Rachel Cooke Matthew Walker has learned to dread the question “What do you do?” At parties, it signals the end of his evening; thereafter, his new acquaintance will inevitably cling to him like ivy. On an aeroplane, it usually means that while everyone else watches movies or reads a thriller, he will find himself running an hours-long salon for the benefit of passengers and crew alike. “I’ve begun to lie,” he says. “Seriously. I just tell people I’m a dolphin trainer. It’s better for everyone.” Walker is a sleep scientist. To be specific, he is the director of the Center for Human Sleep Science at the University of California, Berkeley, a research institute whose goal – possibly unachievable – is to understand everything about sleep’s impact on us, from birth to death, in sickness and health. No wonder, then, that people long for his counsel. As the line between work and leisure grows ever more blurred, rare is the person who doesn’t worry about their sleep. But even as we contemplate the shadows beneath our eyes, most of us don’t know the half of it – and perhaps this is the real reason he has stopped telling strangers how he makes his living. When Walker talks about sleep he can’t, in all conscience, limit himself to whispering comforting nothings about camomile tea and warm baths. It’s his conviction that we are in the midst of a “catastrophic sleep-loss epidemic”, the consequences of which are far graver than any of us could imagine. This situation, he believes, is only likely to change if government gets involved. Walker has spent the last four and a half years writing Why We Sleep, a complex but urgent book that examines the effects of this epidemic close up, the idea being that once people know of the powerful links between sleep loss and, among other things, Alzheimer’s disease, cancer, diabetes, obesity and poor mental health, they will try harder to get the recommended eight hours a night (sleep deprivation, amazing as this may sound to Donald Trump types, constitutes anything less than seven hours). © 2017 Guardian News and Media Limited

Keyword: Sleep
Link ID: 24105 - Posted: 09.25.2017

By STEPH YIN Worms and fish do it. Birds and bees do it. But do jellyfish fall asleep? It seems like a simple question, but answering it required a multistep investigation by a trio of Caltech graduate students. Their answer, published Thursday in Current Biology, is that at least one group of jellyfish called Cassiopea, or the upside-down jellyfish, does snooze. The finding is the first documented example of sleep in an animal with a diffuse nerve net, a system of neurons that are spread throughout an organism and not organized around a brain. It challenges the common notion that sleep requires a brain. It also suggests sleep could be an ancient behavior because the group that includes jellyfish branched off from the last common ancestor of most living animals early on in evolution. Working together was natural for Claire Bedbrook, Michael Abrams and Ravi Nath. The three leading co-authors of the paper are all Ph.D. candidates in biology at the California Institute of Technology and close friends. The project started with an observation by Mr. Abrams that some upside-down jellyfish in his lab would immediately slow their pulsing when the lights were turned off. Over coffee one evening, he discussed this phenomenon with Mr. Nath, who had been studying sleep in roundworms and pondering whether other “simple” animals slept. The two decided to visit Mr. Abrams’s lab in the middle of the night, to see how the jellyfish were behaving. The Cassiopea, or upside-down, jellyfish, demonstrated patterns of behavior consistent with sleep, according to an experiment conducted by Caltech graduate students. Credit Jan Easter Photography In the darkened lab, they observed a tankful of jellyfish pulsing infrequently and staying still for long periods of time — jellyfish that looked, in other words, like they were sleeping. Ms. Bedbrook started to believe they were onto something. © 2017 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 24097 - Posted: 09.22.2017

Carrie Arnold The purpose and evolutionary origins of sleep are among the biggest mysteries in neuroscience. Every complex animal, from the humblest fruit fly to the largest blue whale, sleeps — yet scientists can’t explain why any organism would leave itself vulnerable to predators, and unable to eat or mate, for a large portion of the day. Now, researchers have demonstrated for the first time that even an organism without a brain — a kind of jellyfish — shows sleep-like behaviour, suggesting that the origins of sleep are more primitive than thought. Researchers observed that the rate at which Cassiopea jellyfish pulsed their bell decreased by one-third at night, and the animals were much slower to respond to external stimuli such as food or movement during that time. When deprived of their night-time rest, the jellies were less active the next day. “Everyone we talk to has an opinion about whether or not jellyfish sleep. It really forces them to grapple with the question of what sleep is,” says Ravi Nath, the paper’s first author and a molecular geneticist at the California Institute of Technology (Caltech) in Pasadena. The study was published on 21 September in Current Biology1. “This work provides compelling evidence for how early in evolution a sleep-like state evolved,” says Dion Dickman, a neuroscientist at the University of Southern California in Los Angeles. Nath is studying sleep in the worm Caenorhabditis elegans, but whenever he presented his work at research conferences, other scientists scoffed at the idea that such a simple animal could sleep. The question got Nath thinking: how minimal can an animal’s nervous system get before the creature lacks the ability to sleep? Nath’s obsession soon infected his friends and fellow Caltech PhD students Michael Abrams and Claire Bedbrook. Abrams works on jellyfish, and he suggested that one of these creatures would be a suitable model organism, because jellies have neurons but no central nervous system. Instead, their neurons connect in a decentralized neural net. © 2017 Macmillan Publishers Limited

Keyword: Sleep; Evolution
Link ID: 24096 - Posted: 09.22.2017

By Ariana Eunjung Cha Over the past two decades, U.S. parents and teachers have reported epidemic levels of children with trouble focusing, impulsive behavior and so much energy that they are bouncing off walls. Educators, policymakers and scientists have referred to attention-deficit/hyperactivity disorder, or ADHD, as a national crisis and have spent billions of dollars looking into its cause. They've looked at genetics, brain development, exposure to lead, the push for early academics, and many other factors. But what if the answer to at least some cases of ADHD is more obvious? What if, as a growing number of researchers are proposing, many kids today simply aren't getting the sleep they need, leading to challenging behaviors that mimic ADHD? That provocative and controversial theory has been gaining momentum in recent years, with several studies suggesting strong links between ADHD and the length, timing and quality of sleep. In an era in which even toddlers know the words Netflix and Hulu, when demands for perfectionism extend to squirmy preschoolers and many elementary-age students juggle multiple extracurricular activities each day, one question is whether some kids are so stimulated or stressed that they are unable to sleep as much or as well as they should. Growing evidence suggests that a segment of children with ADHD are misdiagnosed and actually suffer from insufficient sleep, insomnia, obstructed breathing or another known sleep disorder. But the most paradigm-challenging idea may be that ADHD may itself be a sleep disorder. If correct, this idea could fundamentally change the way ADHD is studied and treated. © 1996-2017 The Washington Post

Keyword: ADHD; Sleep
Link ID: 24092 - Posted: 09.21.2017

Aaron E. Carroll Many high-school-aged children across the United States now find themselves waking up much earlier than they’d prefer as they return to school. They set their alarms, and their parents force them out of bed in the morning, convinced that this is a necessary part of youth and good preparation for the rest of their lives. It’s not. It’s arbitrary, forced on them against their nature, and a poor economic decision as well. The National Heart, Lung and Blood Institute recommends that teenagers get between nine and 10 hours of sleep. Most in the United States don’t. It’s not their fault. My oldest child, Jacob, is in 10th grade. He plays on the junior varsity tennis team, but his life isn’t consumed by too many extracurricular activities. He’s a hard worker, and he spends a fair amount of time each evening doing homework. I think most nights he’s probably asleep by 10 or 10:30. His school bus picks him up at 6:40 a.m. To catch it, he needs to wake up not long after 6. Nine hours of sleep is a pipe dream, let alone 10. There’s an argument to be made that we should cut back on his activities or make him go to bed earlier so that he gets more sleep. Teens aren’t wired for that, though. They want to go to bed later and sleep later. It’s not the activities that prevent them from getting enough sleep — it’s the school start times that require them to wake up so early. More than 90 percent of high schools and more than 80 percent of middle schools start before 8:30 a.m. Some argue that delaying school start times would just cause teenagers to stay up later. Research doesn’t support that idea. A systematic review published a year ago examined how school start delays affect students’ sleep and other outcomes. Six studies, two of which were randomized controlled trials, showed that delaying the start of school from 25 to 60 minutes corresponded with increased sleep time of 25 to 77 minutes per week night. In other words, when students were allowed to sleep later in the morning, they still went to bed at the same time, and got more sleep. © 2017 The New York Times Company

Keyword: Biological Rhythms; Development of the Brain
Link ID: 24060 - Posted: 09.13.2017

By Clare Wilson Have we had our first peek at the source of nightmares? When rats are given a fright while they are awake, the fear centre of their brains gets reactivated when they next go to sleep. This could explain why people who go through frightening experiences often have nightmares afterwards, says György Buzsáki of New York University. Rats store mental maps of the world they experience in their hippocampi – two curved structures in the brain. Different places are processed by distinct groups of neurons in the hippocampi that fire together in sequence as rats run around a maze, for example. Later, after exploring an environment like this, these firing sequences have been seen replaying as the animals sleep, as if dreaming of the routes they’d taken. This process is thought to allow memories to become consolidated for longer term storage, and has recently been detected in people for the first time. Buzsáki’s team wondered if such memory replay might include not just spatial information but also how the animal was feeling at the time. They tested this by giving a rat an unpleasant but harmless experience – a puff of air in the face from a computer keyboard cleaner – at a particular spot along a route. As expected, the rats learned to fear that particular place. “They slow down before the location of the air puff, then run superfast away from it,” says Buzsáki’s colleague, Gabrielle Girardeau. “If you do it in the face of a human, they don’t like it either.” © Copyright New Scientist Ltd.

Keyword: Sleep; Learning & Memory
Link ID: 24058 - Posted: 09.12.2017

By Andy Coghlan A type of therapy originally designed for insomnia has been found to also help a range of mental health issues, including negative thoughts, anxiety, depression and psychosis. Daniel Freeman, at the University of Oxford, and his colleagues have been testing Sleepio, a type of cognitive behavioural therapy available online. The ten-week course is intended to restore healthy sleep patterns in people with insomnia, and Freeman wanted to see if it could also relieve other problems. Learn more about the science of sleep: In our expert talk at New Scientist Live in London His team asked nearly 1900 students who have difficulty sleeping to try using Sleepio, and nearly 1870 others to try following standard advice for insomnia. Both groups filled in questionnaires beforehand that assessed their sleep patterns, as well as tendencies to experience paranoia and hallucinations. They repeated these questionnaires at three, ten and 22 weeks into the experiment. Overall, those using Sleepio slept 50 per cent better than the control group, says Freeman. Compared to this group, the Sleepio users also had a 30 per cent reduction in hallucinations, 25 per cent reduction in paranoia, and their anxiety and depression levels were 20 per cent lower. © Copyright New Scientist Ltd.

Keyword: Sleep; Depression
Link ID: 24044 - Posted: 09.07.2017

By TARA PARKER-POPE It started as a simple conversation about a child’s birthday party. But it quickly escalated into a full-blown marital rift. She accused him of neglecting the family. He said she was yelling. “Whatever,” she said. “Go. Go.” “Go where?” he replied. “I don’t know,” she told him. “I don’t want to talk to you anymore.” The bickering parents were among 43 couples taking part in an Ohio State University study exploring how marital interactions influence a person’s health. Every couple in the study — just like couples in the real world — had experienced some form of routine marital conflict. Hot-button topics included managing money, spending time together as a family or an in-law intruding on the relationship. But while marital spats were universal among the couples, how they handled them was not. Some couples argued constructively and even with kindness, while others — like the couple fighting about the birthday party — were hostile and negative. What made the difference? The hostile couples were most likely to be those who weren’t getting much sleep. “When people have slept less, it’s a little like looking at the world through dark glasses,” said Janice Kiecolt-Glaser, a longtime relationship scientist and director of the Ohio State Institute for Behavioral Medicine Research. “Their moods are poorer. We’re grumpier. Lack of sleep hurts the relationship.” The men and women in the study had been married from three to 27 years. They reported varying amounts of sleep — anywhere from three and a half to nine hours a night. Each couple made two visits to the lab, where the partners were prodded to talk about the issues that caused the most conflict in their relationship. Then the researchers analyzed videos of their exchanges using well-established scoring techniques to assess positive and negative interactions and hostile and constructive responses. After all the data were parsed, a clear pattern emerged. © 2017 The New York Times Company

Keyword: Sleep; Emotions
Link ID: 24034 - Posted: 09.05.2017

By Katie Moritz If you’re like a lot of people all over the world, you have a hard time sleeping. Maybe you’ve tried apps that promote sleep, or going without electronics for the hours leading up to bedtime, or supplements like melatonin or magnesium. But have you tried thinking differently about your waking life? Research suggests that having a purpose in life leads to a better night’s sleep. Picture in your mind your biggest interests and your loftiest goals. Pursuing those could help you get better shut-eye. A research team at the Northwestern University Feinberg School of Medicine looked at the sleep habits of more than 800 older adults—though they said the results are likely applicable to everyone—and found that the ones who reported having a purpose in life have fewer sleep disturbances like sleep apnea and restless leg syndrome and sleep better over a long period. Purpose pbs rewire“Helping people cultivate a purpose in life could be an effective drug-free strategy to improve sleep quality, particularly for a population that is facing more insomnia,” said Jason Ong, one of the study’s authors and an associate professor of neurology at the Feinberg School of Medicine, to the university. “Purpose in life is something that can be cultivated and enhanced through mindfulness therapies.” In the Northwestern study, the people who felt their lives had meaning were 63 percent less likely to have sleep apnea, 52 percent less likely to have restless leg syndrome and had better sleep quality. Poor sleep quality is defined by having trouble falling and staying asleep and feeling tired during the day.

Keyword: Sleep; Depression
Link ID: 23967 - Posted: 08.17.2017

By NICHOLAS BAKALAR Children who sleep less may be at increased risk for Type 2 diabetes, researchers report. Earlier studies found a link between shorter sleep and diabetes in adults, but the connection has been little studied in children. British researchers studied 4,525 9- and 10-year olds from varying ethnic backgrounds. On average, their parents reported they slept 10 hours a night, with 95 percent sleeping between eight and 12 hours. The study, in Pediatrics, found that the less sleep, the more likely the children were to have higher body mass indexes, higher insulin resistance and higher glucose readings. All three are risk factors for Type 2 diabetes. Over all, increasing weekday sleep duration by an hour was associated with a 0.2 lower B.M.I. and a 3 percent reduction in insulin resistance. The reasons for the link remain unclear, but the researchers suggest that poor sleep may affect appetite regulation, leading to overeating and obesity. This observational study could not establish cause and effect. Still, the senior author, Christopher G. Owen, a professor of epidemiology at St. George’s University of London, said that for children, the more sleep the better — there is no threshold. “Increasing sleep is a very simple, low-cost intervention,” he said. “We should be doing our utmost to make sure that children sleep for an adequate amount of time.” © 2017 The New York Times Company

Keyword: Sleep; Obesity
Link ID: 23957 - Posted: 08.15.2017

By MALIA WOLLAN ‘‘Don’t startle the person,’’ says Charlene Gamaldo, the medical director at the Johns Hopkins Center for Sleep. Sleepwalkers exist in a semiwakeful state and can become testy and disoriented when forced to come to full consciousness. Instead, speak to them in a quiet voice and lead them gently back to their bed. In most cases, they’ll settle easily and in the morning remember nothing of their nighttime ambulations. To determine whether you’re dealing with a sleepwalker, as opposed to, say, a night owl (or someone with another, more worrisome form of parasomnia), watch for open eyes, a blank expression, physical clumsiness and a lack of reactivity. ‘‘They look zoned out,’’ Gamaldo says. Sleepwalkers tend to perform tasks from memory, including texting, shopping online, cooking and even driving and having sex, all with a noticeably odd flair. ‘‘They may get up and eat a raw TV dinner,’’ Gamaldo says. Researchers attribute a surge in sleepwalking in the 21st century to a rise in the use of hypnosedative sleeping medications. A popular hotel chain in the United Kingdom even issued sleepwalker-care guidelines to staff members after noting a sevenfold increase in sleepwalking patrons over one year, 95 percent of whom were men wandering out of their rooms naked. Other triggers include stress, genetics, fatigue, heat and what Gamaldo calls ‘‘poor sleep hygiene,’’ or loud, overly bright bedrooms filled with TVs and digital devices. To protect a sleepwalker in your home, make it as safe and soporific as possible. Keep him or her away from stairs and sharp objects. ‘‘The bedroom should be uncluttered,’’ Gamaldo says. © 2017 The New York Times Company

Keyword: Sleep
Link ID: 23951 - Posted: 08.12.2017

Thomas Cronin We humans are uncommonly visual creatures. And those of us endowed with normal sight are used to thinking of our eyes as vital to how we experience the world. Vision is an advanced form of photoreception – that is, light sensing. But we also experience other more rudimentary forms of photoreception in our daily lives. We all know, for instance, the delight of perceiving the warm sun on our skin, in this case using heat as a substitute for light. No eyes or even special photoreceptor cells are necessary. But scientists have discovered in recent decades that many animals – including human beings – do have specialized light-detecting molecules in unexpected places, outside of the eyes. These “extraocular photoreceptors” are usually found in the central nervous system or in the skin, but also frequently in internal organs. What are light-sensing molecules doing in places beyond the eyes? Vision depends on detecting light All the visual cells identified in animals detect light using a single family of proteins, called the opsins. These proteins grab a light-sensitive molecule – derived from vitamin A – that changes its structure when exposed to light. The opsin in turn changes its own shape and turns on signaling pathways in photoreceptor cells that ultimately send a message to the brain that light has been detected. © 2010–2017, The Conversation US, Inc.

Keyword: Biological Rhythms; Vision
Link ID: 23947 - Posted: 08.11.2017

By Philip Jaekl In 1959, two French scientists, Michel Jouvet and François Michel, recorded strange patterns of neural activity in the brainstem of sleeping cats. The brain waves seemed remarkably synced to rapid eye movement (REM) sleep, which University of Chicago researchers had connected with dreaming six years earlier. These new brain activity patterns seemed as though they might also correspond with dreaming. In the 1960s, Jouvet and collaborators showed that cats with a lesion introduced into that same brainstem area—the pons—exhibited odd behavior. Cats displayed REMs as though they were asleep, while reacting to nonexistent prey or predators, pouncing, or hiding. Humans can also experience REMs while dreaming, hallucinating, or even recalling deeply emotional memories while awake. But do humans also exhibit the same patterns of neural activity—dubbed PGO waves? The waves are so named because they are generated in a part of the brain stem called the pons, and propagate to the lateral geniculate nuclei of the brain—relay stations in the thalamus for incoming visual information—and then to the occipital lobe, where most visual processing takes place. Studies have suggested that this neural pathway is crucial for functions ranging from basic ones such as the control of eye muscle movements to more-complex phenomena, including visual experiences during dreams and in hallucinations, memory consolidation, and even psychotic behavior. Researchers have recently proposed that a common thread shared by these phenomena is the overriding of retinal visual input by internally created visual experiences (Front Hum Neuro, doi.org/10.3389/fnhum.2017.00089, 2017). © 1986-2017 The Scientist

Keyword: Sleep; Vision
Link ID: 23940 - Posted: 08.10.2017

Amy Maxmen Despite strides in maternal medicine, premature birth remains a vexing problem for obstetricians worldwide. But an analysis of medical records from almost 3 million pregnant women in California1 suggests that a surprisingly simple intervention — better sleep — might help to address the issue. Researchers found that women who had been diagnosed with insomnia or sleep apnea were about twice as likely as women without sleep disorders to deliver their babies more than six weeks early. “It seems obvious, but strangely this study has not been done before,” says Laura Jelliffe-Pawlowski, an epidemiologist at the University of California, San Francisco (UCSF), and an author of the research, which was published on 8 August in the journal Obstetrics and Gynecology1. “Seeing this relationship is important because we are just starved for interventions that can make a difference.” Public-health experts say that better treatment for pregnant women with serious sleep disorders could save babies' lives, and do so with approaches that avoid the use of medication. Every year, 15 million babies worldwide are born prematurely — more than three weeks before the typical full-term pregnancy of 40 weeks. These children have less time to develop in the womb, and 1.1 million will die from birth-related complications. Many others are left with hearing impairment, learning disabilities, cerebral palsy and other health issues. © 2017 Macmillan Publishers Limited,

Keyword: Sleep; Development of the Brain
Link ID: 23937 - Posted: 08.09.2017

By Ben Guarino A sleeping brain can form fresh memories, according to a team of neuroscientists. The researchers played complex sounds to people while they were sleeping, and afterward the sleepers could recognize those sounds when they were awake. The idea that humans can learn while asleep, a concept sometimes called hypnopedia, has a long and odd history. It hit a particularly strange note in 1927, when New York inventor A. B. Saliger debuted the Psycho-phone. He billed the device as an “automatic suggestion machine.” The Psycho-phone was a phonograph connected to a clock. It played wax cylinder records, which Saliger made and sold. The records had names like “Life Extension,” “Normal Weight” or “Mating.” That last one went: “I desire a mate. I radiate love … My conversation is interesting. My company is delightful. I have a strong sex appeal.” Thousands of sleepers bought the devices, Saliger told the New Yorker in 1933. (Those included Hollywood actors, he said, though he declined to name names.) Despite his enthusiasm for the machine — Saliger himself dozed off to “Inspiration” and “Health” — the device was a bust. But the idea that we can learn while unconscious holds more merit than gizmos named Psycho-phone suggest. In the new study, published Tuesday in the journal Nature Communications, neuroscientists demonstrated that it is possible to teach acoustic lessons to sleeping people. © 1996-2017 The Washington Post

Keyword: Sleep; Learning & Memory
Link ID: 23936 - Posted: 08.09.2017

By Matthew Hutson Every year, tens of millions of Americans toss and turn with chronic sleep disorders. But diagnosis isn’t easy: It usually means sleeping in a lab entangled in gadgets that track breathing, heart rate, movement, and brain activity, followed by expert analysis of the data. Now, a new technique that uses machine learning and radio signals can get rid of the sleep lab—and the expert. First, an in-home device bounces radio waves—similar to those in cellphones and Wi-Fi routers—off the sleeper, measuring the returning signal. Then, the system builds on previous radio-frequency sleep monitoring by using three machine-learning algorithms to analyze breathing and pulse and identify the stage of sleep: light, deep, REM, or wakefulness. One algorithm uses a type of neural network common in image recognition to parse the spectrograms, or snapshots, of the data; another uses a type of neural net typically employed in tracking temporal patterns to look at the dynamics of sleep stages; a third refines the analysis to make it more generalizable across people and environments. Researchers trained the tool on about 70,000 30-second sleep intervals and tested it on about 20,000. Measured against an electroencephalogram system that was about as proficient as humans, the system identified sleep stages with 80% accuracy, versus 64% for the previous best radio frequency method, the researchers will report tomorrow at the International Conference on Machine Learning in Sydney, Australia. If the system makes it to market, doctors might soon be able to diagnose you in their sleep. © 2017 American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 23932 - Posted: 08.09.2017

By Ariana Eunjung Cha By now, the connection between sleep and weight gain has been well established. Numerous studies have provided evidence that sleeping too little — less than five hours — messes with your hormones, slows down your metabolism and reprograms your body to eat more. But just how serious are the consequences in terms of numbers? A new study published in PLOS One takes a stab at this question by studying the relationship between sleep duration and a number of quantifiable factors: waist circumference, blood pressure, lipids, glucose, thyroid hormones and other important measures of a person's metabolic profile. The research, led by the Leeds Institute of Cardiovascular and Metabolic Medicine and the School of Food Science and Nutrition, involved 1,615 people ages 19 to 65 in Great Britain. The most striking suggestion was that getting insufficient sleep may make you go up a clothing size. People in the study who were sleeping an average of six hours each night had waist measurements about 1.2 inches (or 3 centimeters) more than those getting nine hours of sleep a night. Those with less sleep also weighed more. The relationship between more sleep and smaller waists and a lower body mass index (BMI) appeared to be almost linear, as shown below. The findings appear to contradict other studies that show that too much sleep — nine hours or more — might have a similar impact on the body as too little sleep. This new study appears to show that waist circumference and BMI are lowest for those with 12 hours of sleep. The theory of why this relationship exists has to do with two hormones that help tell you when to eat and when to stop. Less sleep upsets the balance, making you eat more. Combine that with the slower metabolism that people with lack of sleep appear to have it's no wonder that people are prone to becoming larger and gaining weight. © 1996-2017 The Washington Post

Keyword: Sleep; Obesity
Link ID: 23903 - Posted: 08.01.2017

By Helen Thomson Have you recently arrived at work naked or turned up for an exam without revising? If you want to avoid having nightmares like these, it might be best to get less than 9 hours’ sleep a night. People often have nightmares following upsetting events, and research into nightmares has mostly focused on people with conditions like post-traumatic stress disorder (PTSD). But most people get nightmares at some point, prompting Stephanie Rek at the University of Oxford and her colleagues to perform one of the largest ever studies of nightmares in the general population. Discover the new science of sleep and dreaming: Learn more at New Scientist Live in London The team recruited 846 people through media advertisements and databases of people interested in sleep studies, and asked them to complete an online survey. The participants were asked questions such as how many nightmares they had experienced over the past two weeks, and how bad they were. These answers contributed to an overall score on a “nightmare severity scale”. Each volunteer was also assessed for PTSD and asked about other aspects of their life, such as recent divorces or legal trouble, their tendency to worry, how much sleep they get and how much alcohol they drink. © Copyright New Scientist Ltd.

Keyword: Sleep
Link ID: 23894 - Posted: 07.29.2017

By Tara Bahrampour Older patients who become disoriented or confused after surgery are more than three times more likely to develop dementia later, a new study has found. The report, published Friday by the British Journal of Anaesthesia, assesses the effects of post-operative delirium (POD) on people 65 and older who were cognitively normal before their operations. Of 1,152 such patients, 9.5 percent met criteria for mild cognitive impairment or dementia a median of nine months after surgery. The frequency of being diagnosed with MCI or dementia after surgery was much higher – 33.3 percent – among those who had experienced post-operative delirium, compared with 9 percent among those who had not. While earlier studies have showed a relationship between POD and dementia, this is the first to look entirely at subjects who showed no cognitive decline in pre-surgery assessments, said David Warner, an anesthesiologist at Mayo Clinic in Rochester, Minnesota and the study’s senior author. Delirium is defined by an acute state of confusion, inattention, disorganized thinking, and a fluctuating mental state. Older patients are more likely than younger ones to develop it after surgery, as are people with lower education levels and those who undergo vascular procedures. Further study is needed to determine whether delirium contributes to later cognitive decline or is an indicator of some underlying factor that made people more likely to develop dementia, Warner said. © 1996-2017 The Washington Post

Keyword: Alzheimers
Link ID: 23888 - Posted: 07.28.2017