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You may have read that having a male brain will earn you more money. Or maybe that female brains are better at multitasking. But there is no such thing as a female or male brain, according to the first search for sex differences across the entire human brain. It reveals that most people have a mix of male and female brain features. And it also supports the idea that gender is non-binary, and that gender classifications in many situations are meaningless. “This evidence that human brains cannot be categorised into two distinct classes is new, convincing, and somehow radical,” says Anelis Kaiser at the University of Bern, Switzerland. The idea that people have either a “female” or “male” brain is an old one, says Daphna Joel at Tel Aviv University in Israel. “The theory goes that once a fetus develops testicles, they secrete testosterone which masculinises the brain,” she says. “If that were true, there would be two types of brain.” To test the theory, Joel and her colleagues looked for differences in brain scans taken from 1400 people aged between 13 and 85. The team looked for variations in the size of brain regions as well as the connections between them. In total, the group identified 29 brain regions that generally seem to be different sizes in self-identified males and females. These include the hippocampus, which is involved in memory, and the inferior frontal gyrus, which is thought to play a role in risk aversion. When the group looked at each individual brain scan, however, they found that very few people had all of the brain features they might be expected to have, based on their sex. Across the sample, between 0 and 8 per cent of people had “all-male” or “all-female” brains, depending on the definition. “Most people are in the middle,” says Joel. © Copyright Reed Business Information Ltd.
Keyword: Sexual Behavior
Link ID: 21670 - Posted: 12.01.2015
By Kelli Whitlock Burton Evolutionarily speaking, we are born to make babies. Our bodies—and brains—don’t fall apart until we come to the end of our child-bearing years. So why are grandmothers, who don’t reproduce and who contribute little to food production, still around and still mentally sound? A new study offers an intriguing genetic explanation. Scientists have proposed several explanations for why our species lives as long and as healthily as it does. One idea is that grandmothers help out with child rearing. A 1998 study found, for example, that a Hadza group of hunter-gatherers in Tanzania had more babies if grandmothers helped feed their newly-weaned young grandchildren. The researchers speculated this kind of care freed up young mothers to reproduce, and ensured that the caregiver grandmother’s genes were passed on to more young. They called their theory the “grandmother hypothesis.” But grandmothers need to have all their wits about them to help out in this way, and the new study may explain how this happens. Physician-scientist Ajit Varki and evolutionary biologist Pascal Gagneux of the University of California, San Diego, arrived at the findings accidentally. The pair was studying a gene that helps control the body’s inflammatory and immune response to injury or infection. Previous studies have linked two forms of the gene—CD33—to Alzheimer’s disease. While one CD33 variant, or allele, predisposes a person to the disease, the other appears to protect against it by preventing the formation of protein clumps in the brain. © 2015 American Association for the Advancement of Science.
By Diana Kwon The human brain is unique: Our remarkable cognitive capacity has allowed us to invent the wheel, build the pyramids and land on the moon. In fact, scientists sometimes refer to the human brain as the “crowning achievement of evolution.” But what, exactly, makes our brains so special? Some leading arguments have been that our brains have more neurons and expend more energy than would be expected for our size, and that our cerebral cortex, which is responsible for higher cognition, is disproportionately large—accounting for over 80 percent of our total brain mass. Suzana Herculano-Houzel, a neuroscientist at the Institute of Biomedical Science in Rio de Janeiro, debunked these well-established beliefs in recent years when she discovered a novel way of counting neurons—dissolving brains into a homogenous mixture, or “brain soup.” Using this technique she found the number of neurons relative to brain size to be consistent with other primates, and that the cerebral cortex, the region responsible for higher cognition, only holds around 20 percent of all our brain’s neurons, a similar proportion found in other mammals. In light of these findings, she argues that the human brain is actually just a linearly scaled-up primate brain that grew in size as we started to consume more calories, thanks to the advent of cooked food. Other researchers have found that traits once believed to belong solely to humans also exist in other members of the animal kingdom. Monkeys have a sense of fairness. Chimps engage in war. Rats show altruism and exhibit empathy. In a study published last week in Nature Communications, neuroscientist Christopher Petkov and his group at Newcastle University found that macaques and humans share brain areas responsible for processing the basic structures of language. © 2015 Scientific American
Angus Chen Loneliness has been linked to everything from heart disease to Alzheimer's disease. Depression is common among the lonely. Cancers tear through their bodies more rapidly, and viruses hit them harder and more frequently. In the short term, it feels like the loneliness will kill you. A study suggests that's because the pain of loneliness activates the immune pattern of a primordial response commonly known as fight or flight. For decades, researchers have been seeing signs that the immune systems of lonely people are working differently. Lonely people's white blood cells seem to be more active in a way that increases inflammation, a natural immune response to wounding and bacterial infection. On top of that, they seem to have lower levels of antiviral compounds known as interferons. That seemed to provide a link to a lot of the poor health outcomes associated with loneliness, since chronic inflammation has been linked to everything from cancer to depression. The human body isn't built to hold a high level of inflammation for years. "That explains very clearly why lonely people fall at increased risk for cancer, neurodegenerative disease and viral infections as well," says Steve Cole, a genomics researcher at the University of California, Los Angeles, and lead author on the study published in the Proceedings of the National Academy of Sciences on Monday But it still doesn't explain how or why loneliness could change our bodies. To find that out, Cole and his collaborators tracked 141 people over five years. Every year, the researchers measured how lonely the participants felt and took blood samples to track the activity of genes involved with immunity and inflammation. © 2015 npr
Helen Thompson Just after dawn, barbershop quartets of male howler monkeys echo over the canopy of Mexico’s forests. Jake Dunn remembers them well from his early fieldwork in Veracruz. “Most people who don’t know what they’re listening to assume it’s a jaguar,” says Dunn, a primatologist at the University of Cambridge. The calls serve as a warning to male competitors and an alluring pickup line for females. While studying primates in Mexico, Dunn heard drastic differences between resident howler monkeys. He and his colleagues decided to pin down the origin and evolution of this well-known variation among species. After reading a 1949 paper that classified howlers based on a vocal tract bone called the hyoid, Dunn paired up with Lauren Halenar of the American Museum of Natural History in New York City, who was studying the hyoid’s role in howler biology. Scouring collections at museums and zoos in the United States and Europe, the team used laser scanners to create 3-D models of hyoids from nine howler species. The work required a lot of digging through cupboards for skeletons. “Some of these specimens are hundreds of years old,” says Dunn, who recalls imagining “the early naturalists hunting these animals and bringing back the collections.” Real pay dirt came from the National Museums of Scotland, which had preserved the remains of two howlers that had died of natural causes in zoos. CT and MRI scans of the two specimens provided a rare peek at the howler vocal system’s layout. © Society for Science & the Public 2000 - 2015.
Ian Sample Science editor High-strength cannabis may damage nerve fibres that handle the flow of messages across the two halves of the brain, scientists claim. Brain scans of people who regularly smoked strong skunk-like cannabis revealed subtle differences in the white matter that connects the left and right hemispheres and carries signals from one side of the brain to the other. The changes were not seen in those who never used cannabis or smoked only the less potent forms of the drug, the researchers found. The study is thought to be the first to look at the effects of cannabis potency on brain structure, and suggests that greater use of skunk may cause more damage to the corpus callosum, making communications across the brain’s hemispheres less efficient. Paola Dazzan, a neurobiologist at the Institute of Psychiatry at King’s College London, said the effects appeared to be linked to the level of active ingredient, tetrahydrocannabinol (THC), in cannabis. While traditional forms of cannabis contain 2 to 4 % THC, the more potent varieties (of which there are about 100), can contain 10 to 14% THC, according to the DrugScope charity. “If you look at the corpus callosum, what we’re seeing is a significant difference in the white matter between those who use high potency cannabis and those who never use the drug, or use the low-potency drug,” said Dazzan. The corpus callosum is rich in cannabinoid receptors, on which the THC chemical acts. © 2015 Guardian News and Media Limited
Sara Reardon Suicide is a puzzle. Fewer than 10% of people with depression attempt suicide, and about 10% of those who kill themselves were never diagnosed with any mental-health condition. Now, a study is trying to determine what happens in the brain when a person attempts suicide, and what sets such people apart. The results could help researchers to understand whether suicide is driven by certain brain biology — and is not just a symptom of a recognized mental disorder. The project, which launched this month, will recruit 50 people who have attempted suicide in the two weeks before enrolling in the study. Carlos Zarate, a psychiatrist at the US National Institute of Mental Health in Bethesda, Maryland, and his colleagues will compare these people's brain structure and function to that of 40 people who attempted suicide more than a year ago, 40 people with depression or anxiety who have never attempted suicide and a control group of 40 healthy people. In doing so, the researchers hope to elucidate the brain mechanisms associated with the impulse to kill oneself. Zarate's team will also give ketamine, a psychoactive ‘party drug’, to the group that has recently attempted suicide. Ketamine, which is sometimes used to treat depression, can quickly arrest suicidal thoughts and behaviour — even in cases when it does not affect other symptoms of depression1. The effect is known to last for about a week. © 2015 Nature Publishing Group,
In Greek mythology, the Hydra was a gigantic, snake-like monster with nine heads and poisonous blood and breath, which lurked in the swamps of Lerna. Heracles was sent to destroy the beast as one of his twelve labours, but when he decapitated one of its heads, two more grew back in its place. He eventually defeated it with the help of his trusty nephew Iolaus, however, by burning out the severed roots with firebrands to prevent the regrowth, then decapitating its one immortal head and burying it under a heavy rock. The real Hydra has regenerative capacities that surpass those of its mythological namesake. When it is dismembered, any fragment of its body can regenerate to form a completely new individual, and it can even remain alive after its entire nervous system has been lost. Researchers in Switzerland now report that it does so by adapting its skin cells to make them behave more like neurons. Their findings provide clues about how nerve cells first evolved, billions of years ago. Hydra is a small freshwater polyp with a tubular body consisting of just two layers of cells, and a network of nerves that controls its movements, feeding, and its light-sensitive stinging tentacles. The central region of its body contains specialized, multi-purpose skin cells which can contract and detect mechanical stimuli. These so-called ‘i-cells’ also act as stem cells, continuously renewing themselves, while also producing immature nerve cells that migrate out to the extremities, where they differentiate to form the dense nerve net. © 2015 Guardian News and Media Limited
Keyword: Development of the Brain
Link ID: 21663 - Posted: 11.28.2015
By David Noonan The 63-year-old chief executive couldn't do his job. He had been crippled by migraine headaches throughout his adult life and was in the middle of a new string of attacks. “I have but a little moment in the morning in which I can either read, write or think,” he wrote to a friend. After that, he had to shut himself up in a dark room until night. So President Thomas Jefferson, in the early spring of 1807, during his second term in office, was incapacitated every afternoon by the most common neurological disability in the world. The co-author of the Declaration of Independence never vanquished what he called his “periodical head-ach,” although his attacks appear to have lessened after 1808. Two centuries later 36 million American migraine sufferers grapple with the pain the president felt. Like Jefferson, who often treated himself with a concoction brewed from tree bark that contained quinine, they try different therapies, ranging from heart drugs to yoga to herbal remedies. Their quest goes on because modern medicine, repeatedly baffled in attempts to find the cause of migraine, has struggled to provide reliable relief. Now a new chapter in the long and often curious history of migraine is being written. Neurologists believe they have identified a hypersensitive nerve system that triggers the pain and are in the final stages of testing medicines that soothe its overly active cells. These are the first ever drugs specifically designed to prevent the crippling headaches before they start, and they could be approved by the U.S. Food and Drug Administration next year. If they deliver on the promise they have shown in studies conducted so far, which have involved around 1,300 patients, millions of headaches may never happen. © 2015 Scientific American
Keyword: Pain & Touch
Link ID: 21662 - Posted: 11.28.2015
By Nala Rogers If you travel with a group of friends, you might delegate navigation to the person with the best sense of direction. But among homing pigeons, the leader is whoever flies the fastest—even if that pigeon has to pick up navigation skills on the job, according to a new study. To find out how the skills of individual pigeons influence flock direction, researchers tested four flocks on journeys from three different locations, each about 5 kilometers from their home loft near Oxford, U.K. At each site, the researchers tracked the pigeons during solo flights before releasing them together for several group journeys. The fastest birds surged to the front during group flights and determined when the flock turned, despite the fact that these leaders were often poor navigators during their initial solo expeditions. But on a final set of solo flights—made after the group journeys—these same leaders chose straighter routes than followers, the researchers report today in Current Biology. Apparently, being responsible for group decisions helped pigeons learn the route, say scientists, raising questions about the two-way interplay between skills and leadership. © 2015 American Association for the Advancement of Science
Sara Reardon Panzee the chimpanzee was a skilled communicator that could tell untrained humans where to find hidden food by using gestures and vocalizations. Austin the chimp was particularly adept with a computer, and scientists have been scanning its genome for clues to its unusual cognitive abilities. Both apes lived at a language-research centre at Georgia State University in Atlanta, and both died several years ago — but they will live on in an online database of brain scans and behavioural data from nearly 250 chimpanzees. Researchers hope to combine this trove, now in development, with a biobank of chimpanzee brains to enable scientists anywhere in the world to study the animals’ neurobiology. This push to repurpose old data is especially timely now that the US National Institutes of Health (NIH) has decided to retire its remaining research chimpanzees. The agency decommissioned more than 300 animals in 2013, but kept 50 available for research in case of a public-health emergency. Following an 18 November decision, this remaining population will also be sent to sanctuaries in the coming years. The NIH also hopes to retire another 82 chimps that it supports but does not own, says director Francis Collins. “We were on a trajectory toward zero, and today’s the day we’re at zero,” says Jeffrey Kahn, a bioethicist at Johns Hopkins University in Baltimore, Maryland, who led a 2011 study on the NIH chimp colony for the Institute of Medicine. © 2015 Nature Publishing Group
Aimee Cunningham For a child with attention deficit hyperactivity disorder, meeting the daily expectations of home and school life can be a struggle that extends to bedtime. The stimulant medications commonly used to treat ADHD can cause difficulty falling and staying asleep, a study finds. And that can make the next day that much harder. As parents are well aware, sleep affects a child's emotional and physical well-being, and it is no different for those with ADHD. "Poor sleep makes ADHD symptoms worse," says Katherine M. Kidwell, a doctoral student in clinical psychology at the University of Nebraska, Lincoln, who led the study. "When children with ADHD don't sleep well, they have problems paying attention the next day, and they are more impulsive and emotionally reactive." Stimulant medications boost alertness, and some studies have found a detrimental effect on children's sleep. However, other studies have concluded that the stimulants' ameliorating effects improve sleep. The drugs include amphetamines such as Adderall and methylphenidate such as Ritalin. To reconcile the mixed results on stimulants and children's sleep, Kidwell and her colleagues undertook a meta-analysis, a type of study that summarizes the results of existing research. The team found nine studies that met their criteria. These studies compared children who were taking stimulant medication with those who weren't. The studies also randomly assigned children to the experimental group or the control group and used objective measures of sleep quality and quantity, such as assessing sleep in a lab setting or with a wristwatch-like monitor at home rather than a parent's report. © 2015 npr
By Nicholas Bakalar Bright light therapy has been used effectively for seasonal affective disorder, the kind of depression that comes on at a specific time every year, often the dark days of late fall and winter, and then lifts. Now a new study has found that it may work to treat nonseasonal depression as well. Researchers randomly assigned 122 patients, 19 to 60 years old, with major depression to receive one of four treatments: 30 minutes of daily exposure to fluorescent light; 20 milligrams of Prozac daily; both light and Prozac; and a control group that received a dummy pill and exposure to an electric air purifier. The study, in JAMA Psychiatry, lasted eight weeks. Using well-validated scales that quantify depression severity, the researchers found improvements in all four groups. The difference between Prozac alone and the placebo was not statistically significant, but light therapy alone was significantly better than placebo, and light therapy with medication was the most effective treatment of all. “This is the first study to show that light treatment is an option for people with nonseasonal depression, which is much more common than seasonal depression,” said the lead author, Dr. Raymond W. Lam, a professor of psychiatry at the University of British Columbia. “Light treatment can be combined with medicine and psychotherapy, and it’s a safe treatment without a lot of side effects.” © 2015 The New York Times Company
By Virginia Morell Was that fish on your plate once a sentient being? Scientists have long believed that the animals aren’t capable of the same type of conscious thought we are because they fail the “emotional fever” test. When researchers expose birds, mammals (including humans), and at least one species of lizard to new environments, they experience a slight rise in body temperature of 1°C to 2°C that lasts a while; it’s a true fever, as if they were responding to an infection. The fever is linked to the emotions because it’s triggered by an outside stimulus, yet produces behavioral and physiological changes that can be observed. Some scientists argue that these only occur in animals with sophisticated brains that sense and are conscious of what’s happening to them. Previous tests suggested that toads and fish don’t respond this way. Now, a new experiment that gave the fish more choices shows the opposite. Researchers took 72 zebrafish and either did nothing with them or placed them alone in a small net hanging inside a chamber in their tank with water of about 27°C; zebrafish prefer water of about 28°C. After 15 minutes in the net, the team released the confined fish. They could then freely swim among the tank’s five other chambers, each heated to a different temperature along a gradient from 17.92°C to 35°C. (The previous study used a similar setup but gave goldfish a choice between only two chambers, both at higher temperatures.) The stressed fish spent more time—between 4 and 8 hours—in the warmer waters than did the control fish, and raised their body temperatures about 2°C to 4°C, showing an emotional fever, the scientists report online today in the Proceedings of the Royal Society B. Thus, their study upends a key argument against consciousness in fish, they say. © 2015 American Association for the Advancement of Science.
Jon Hamilton A look at the brain's wiring can often reveal whether a person has trouble staying focused, and even whether they have attention deficit hyperactivity disorder, known as ADHD. A team led by researchers at Yale University reports that they were able to identify many children and adolescents with ADHD by studying data on the strength of certain connections in their brains. "There's an intrinsic signature," says Monica Rosenberg, a graduate student and lead author of the study in Nature Neuroscience. But the approach isn't ready for use as a diagnostic tool yet, she says. The finding adds to the evidence that people with ADHD have a true brain disorder, not just a behavioral problem, says Mark Mahone, director of neuropsychology at the Kennedy Krieger institute in Baltimore. "There are measurable ways that their brains are different," he says. The latest finding came from an effort to learn more about brain connections associated with attention. Initially, the Yale team used functional MRI, a form of magnetic resonance imaging, to monitor the brains of 25 typical people while they did something really boring. Their task was to watch a screen that showed black-and-white images of cities or mountains and press a button only when they saw a city. © 2015 npr
by Sarah Zielinski Call someone a “bird brain” and they are sure to be offended. After all, it’s just another way of calling someone “stupid.” But it’s probably time to retire the insult because scientists are finding more and more evidence that birds can be pretty smart. Consider these five species: We may call pigeons “flying rats” for their penchant for hanging out in cities and grabbing an easy meal. (Long before there was “pizza rat,” you know there had to be “pizza pigeons” flying around New York City.) But there may be more going on in their brains than just where to find a quick bite. Richard Levenson of the University of California, Davis Medical Center and colleagues trained pigeons to recognize images of human breast cancers. In tests, the birds proved capable of sorting images of benign and malignant tumors. In fact, they were just as good as humans, the researchers report November 18 in PLOS ONE. In keeping with the pigeons’ reputation, though, food was the reward for their performance. No one would suspect the planet’s second-best toolmakers would be small black birds flying through mountain forests on an island chain east of Australia. But New Caledonian crows have proven themselves not only keen toolmakers but also pretty good problem-solvers, passing some tests that even dogs (and pigeons) fail. For example, when scientists present an animal with a bit of meat on a long string dangling down, many animals don’t ever figure out how to get the meat. Pull it up with one yank, and the meat is still out of reach. Some animals will figure out how to get it through trial and error, but a wild New Caledonian crow solved the problem — pull, step on string, pull some more — on its first try. © Society for Science & the Public 2000 - 2015
By Lenny Bernstein BALTIMORE — Deep into a three-day heroin binge at a local hotel, Samantha told the newbie he was shooting too much. He wasn’t accustomed to heroin, she said, and hadn’t waited long enough since his last injection. “But he didn’t listen,” she said. Sure enough, he emerged from a visit to the bathroom, eyes glazed, and collapsed from an overdose. Samantha, who declined to give her last name to avoid trouble with her bosses at a nearby strip club, said she grabbed her naloxone, the fast-acting antidote to opioid overdoses. She was too panicked to place the atomizer on the end of the syringe, but her boyfriend wasn’t. He sprayed the mist into the nose of the unconscious drug user, who awoke minutes later. “I always have it because I’m scared to death,” said Samantha, who said she has been shooting heroin for 22 years. “I don’t want to be helpless.” As the opioid epidemic has exploded in small towns and suburbs in recent years, officials have scrambled to put naloxone in the hands of drug users’ families and friends, and to make it more widely available by equipping police officers with the drug. At the same time, thousands of lives are being saved by giving the antidote to drug users. More than 80 percent of overdose victims revived by “laypeople” were rescued by other users, most of them in the past few years, according to one national survey published in June.
Keyword: Drug Abuse
Link ID: 21654 - Posted: 11.24.2015
By Karen Weintraub Essential tremor is involuntary shaking – usually of the hands, but sometimes also of the neck, jaw, voice or legs. “Any fine tasks with the hands can be very difficult when the tremor is pronounced,” said Dr. Albert Hung, center director of the Massachusetts General Hospital National Parkinson Foundation Center of Excellence. Essential tremor can affect balance, walking, hearing and cognition, and can get worse over time, said Dr. Elan Louis, chief of the division of movement disorders at Yale School of Medicine. People with essential tremor run almost twice the risk of developing Alzheimer’s as the general population. Essential tremor appears with movement; if people let their hands sit still, they don’t tremble. That is the big difference between an essential tremor and the tremor of Parkinson’s disease, which can occur while at rest, Dr. Louis said. Essential tremor also tends to strike both hands while Parkinson’s is more one-sided at first, said Dr. Hung. The cause of essential tremor remains a mystery, though it seems to run in families. People of any age or sex can have the condition, though it is more common as people grow older. Roughly 4 percent of 40-year-olds have essential tremor, compared with about 20 percent of 90-year-olds, Dr. Louis said. Available treatments “aren’t great,” Dr. Louis said. Two medications – the beta blocker propranolol and the epilepsy drug primidone, sold under the brand name Mysoline – can reduce tremors by 10 to 30 percent, he said, but they work only in about half of patients. Deep brain stimulation – implanting electrodes into the brain to override faulty electrical signals – has been shown to markedly reduce hand tremor severity, he said. But the treatment can worsen cognitive and balance problems and “doesn’t cure the underlying disease. It merely and temporarily lessons a single symptom, which is the tremor.” © 2015 The New York Times Company
Keyword: Movement Disorders
Link ID: 21653 - Posted: 11.24.2015
By John Bohannon It may sound like a bird-brained idea, but scientists have trained pigeons to spot cancer in images of biopsied tissue. Individually, the avian analysts can't quite match the accuracy of professional pathologists. But as a flock, they did as well as trained humans, according to a new study appearing this week in PLOS ONE. Cancer diagnosis often begins as a visual challenge: Does this lumpy spot in a mammogram image justify a biopsy? And do cells in biopsy slides look malignant or benign? Training doctors and medical technicians to tell the difference is expensive and time-consuming, and computers aren't yet up to the task. To see whether a different type of trainee could do better, a team led by Richard Levenson, a pathologist and technologist at the University of California, Davis, and Edward Wasserman, a psychologist at the University of Iowa, in Iowa City, turned to pigeons. In spite of their limited intellect, the bobble-headed birds have certain advantages. They have excellent visual systems, similar to, if not better than, a human's. They sense five different colors as opposed to our three, and they don’t “fill in” the gaps like we do when expected shapes are missing. However, training animals to do a sophisticated task is tricky. Animals can pick up on unintentional cues from their trainers and other humans that may help them correctly solve problems. For example, a famous 20th century horse named Clever Hans was purportedly able to do simple arithmetic, but was later shown to be observing the reactions of his human audience. And although animals can perform extremely well on tasks that are confined to limited circumstances, overtraining on one set of materials can lead to total inaccuracy when the same information is conveyed slightly differently. © 2015 American Association for the Advancement of Science
By Nicholas Bakalar Several studies have shown that there is an association between shift work and an increased risk for heart disease and diabetes. Now a new study, in the Journal of Clinical Endocrinology & Metabolism, has found a similar association in people whose sleeping schedules change on the weekend. For seven days, 447 men and women ages 30 to 54 wore devices that measured movement and tracked when they fell asleep and woke. Almost 85 percent of the group went to sleep and woke later on their days off than during the workweek. The researchers found that the greater the mismatch in sleep timing between weekdays and weekends, the higher the metabolic risk. Sleeping late on days off was linked to lower HDL (good) cholesterol, higher triglycerides, higher insulin resistance and higher body mass index. The associations persisted after controlling for physical activity, caloric intake, alcohol use and other factors. “It’s not clear yet that this is a long-term effect,” said the lead author, Patricia M. Wong, a graduate student at the University of Pittsburgh. “But we think of this as people having to sleep and work out of sync with their internal clock, and that having to be out of sync may be having these health effects.” © 2015 The New York Times Company
Link ID: 21651 - Posted: 11.21.2015