HealthMedicine6

Melatonin can help you get a good night's sleep in a noisy environment

March 19, 2015
Science Daily/BioMed Central
Using melatonin could provide more and better quality sleep compared to using an eye mask and earplugs in a simulated noisy and illuminated environment, according to research. This study was carried out on healthy subjects but could have future implications for intensive care unit patients.

Melatonin is the hormone secreted by the body to regulate sleep, usually in periods of darkness. Synthetically produced melatonin is used to boost the body's own melatonin levels to treat some sleep disorders, and sometimes as a means of overcoming jet lag. In ICUs, disturbances throughout the night, caused by noise and light, have been linked to slower recovery. This has led clinicians to investigate ways of reducing sleep disturbances.

Researchers from Capital Medical University in Beijing recruited 40 healthy participants to study the effects simulated ICU conditions had on sleep patterns. The research was conducted in the sleep lab of Fuzhou Children's Hospital of Fujian Province in collaboration with Professor Ling Shen. For the first four nights all participants underwent a baseline/adjustment period. During this time they slept in a sleep laboratory where on alternating nights a recording from a typical night shift at an ICU was played and light levels were the same as in the hospital.

After the first four nights the participants were randomly divided into four equal groups but continued to sleep in the simulated ICU. The first group did not receive any sleep aid. The second were provided with eye masks and earplugs. The third group took 1mg of fast-release oral melatonin when going to bed. The final group of participants was given a placebo. The participants did not know if they were receiving melatonin or placebo.

During the study period all participants' melatonin levels were tested hourly by taking blood samples. The quality of sleep was assessed using specialist equipment that measured brain activity, eye movement and muscle tension. Anxiety levels and sleep quality were also evaluated by getting participants to self-evaluate the following morning.

It was found that all sleep patterns were disturbed by exposure to the simulated ICU environment. This resulted in feelings of anxiety and reduced quality of sleep. Those participants that used either eye masks and earplugs or oral melatonin had improved sleep. Those who took melatonin were found to have decreased awakenings during the night even compared to the eye mask and earplugs group. The quality of the sleep was also found to be much improved for those taking melatonin, with reported lower anxiety levels and increased REM sleep -- thought to be linked to improved cognitive restoration.

As this study was carried out on a small number of healthy subjects over a nine-hour period it may not give a full representation of the various sleep disturbances that can occur in an ICU over 24 hours. They say future studies will need to be carried out on a larger group of diverse participants. Consideration would also need to be given for the administration of oral melatonin to critically ill patients who may also be taking other medications.

Lead researcher, Professor Xiu-Ming Xi from Fuxing Hospital, Capital Medical University, says: "Both use of oral melatonin and use of earplugs and eye masks improve sleep quality at different levels, especially melatonin. Discomfort from use of earplugs and eye masks might affect sleep quality, which wasn't reported with melatonin. Therefore, compared to earplugs and eye masks, melatonin showed up the better performance in effectiveness and the tolerance of participants."
http://www.sciencedaily.com/releases/2015/03/150319080404.htm

 

Drinking alcohol several times a week increases risk of stroke mortality

March 19, 2014
Science Daily/University of Eastern Finland
Consuming alcohol more frequently than twice a week increases the risk of stroke mortality in men, according to a study. The results show that the effects of alcohol are not limited to the amount consumed, but also the frequency of drinking matters. Other significant risk factors for stroke include elevated blood pressure, coronary artery disease, heart failure, atrial fibrillation, diabetes, smoking, overweight, asymptomatic carotid artery stenosis, and elevated cholesterol levels.

Excessive consumption of alcohol is associated with a variety of different diseases. The relationship between alcohol consumption and ischaemic stroke shows a J curve pattern, which means that in people who are moderate consumers of alcohol, the risk of stroke is the lowest, while heavy consumption of alcohol increases the risk of stroke. The risk of cerebral haemorrhage increases linearly as the consumption of alcohol increases: the higher the amount of alcohol consumed, the higher the risk of stroke. In addition to alcohol, other significant risk factors for stroke include elevated blood pressure, coronary artery disease, heart failure, atrial fibrillation, diabetes, smoking, overweight, asymptomatic carotid artery stenosis, and elevated cholesterol levels.

The study showed that people who consume alcohol more frequently than twice a week have over a threefold risk of stroke mortality than people who do not consume alcohol at all. The risk of stroke mortality is elevated irrespective of the amount of alcohol consumed.

The study is based on follow-up data from the Kuopio Ischaemic Heart Disease Risk Factor Study, KIHD. At the onset of the study, the men participating in the study were middle-aged, and the follow-up time was 20 years. A total of 2,609 men participated in the study. The consumption of alcohol was measured with the help of a Nordic alcohol survey charting the amount of alcohol consumed at one time and the average number of drinking occasions in the preceding 12 months. The data on cases of stroke was obtained from hospital discharge registers, the Finnish Stroke Register, and the National Cause of Death Register maintained by Statistics Finland.
http://www.sciencedaily.com/releases/2014/03/140319085434.htm

 

More flavorful, healthful chocolate could be on its way

March 24, 2015
Science Daily/American Chemical Society
Chocolate has many health benefits -- it can potentially lower blood pressure and cholesterol and reduce stroke risk. But just as connoisseurs thought it couldn't get any better, there's this tasty new tidbit: researchers have found a way to make the treat even more nutritious -- and sweeter.

Cocoa undergoes several steps before it takes shape as a candy bar. Workers cut down pods from cocoa trees, then split open the pods to remove the white or purple cocoa beans. They are fermented in banana-lined baskets for a few days and then set out to dry in the sun. Roasting, the next step, brings out the flavor. But some of the healthful polyphenols (antioxidants) are lost during the roasting process, so the researchers wanted to figure out a way to retain as much of the polyphenols and good flavors as possible.

"We decided to add a pod-storage step before the beans were even fermented to see whether that would have an effect on the polyphenol content," says Emmanuel Ohene Afoakwa, Ph.D., who is at the University of Ghana. "This is not traditionally done, and this is what makes our research fundamentally different. It's also not known how roasting affects polyphenol content."

Afoakwa's team divided 300 pods into four groups that were either not stored at all or stored for three, seven or 10 days before processing. This technique is called "pulp preconditioning." After each storage period passed, fermentation and drying were done as usual. He reports that the seven-day storage resulted in the highest antioxidant activity after roasting.

To assess the effects of roasting, the researchers took samples from each of the storage groups and roasted them at the same temperature for different times. The current process is to roast the beans for 10-20 minutes at 248-266 degrees Fahrenheit, he explains. Afoakwa's team adjusted this to 45 minutes at 242 degrees Fahrenheit and discovered that this slower roasting at a lower temperature increased the antioxidant activity compared to beans roasted with the conventional method.

In addition, the beans that were stored and then roasted for 45 minutes had more polyphenols and higher antioxidant activity than beans whose pods were not stored prior to fermentation, says Afoakwa. He explains that pulp preconditioning likely allowed the sweet pulp surrounding the beans inside the pod to alter the biochemical and physical constituents of the beans before the fermentation. "This aided the fermentation processes and enhanced antioxidant capacity of the beans, as well as the flavor," he says. He adds that the new technique would be particularly useful for countries in Southeast Asia and Latin America where cocoa beans produce a chocolate with a less intense chocolate flavor and have reduced antioxidant activity.

Looking to the future, he says the team will be studying in more detail the effects of roasting on the flavor of freshly picked compared to stored cocoa beans. They will be testing different temperatures and roasting and storing times to determine if even higher amounts of antioxidants can be retained through the process.
http://www.sciencedaily.com/releases/2015/03/150324084800.htm

 

Sleep loss tied to emotional reactions

March 25, 2015
Science Daily/University of Arkansas, Fayetteville
A new book summarizes research on the interplay of sleep and various components of emotion and affect that are related to mood disorders, anxiety disorders, bipolar disorder and depression.

A person's loss of sleep can be connected to their likelihood of reacting emotionally to a stressful situation.

That is one of the recent findings included in a new book, Sleep and Affect: Assessment, Theory and Clinical Implications, co-edited by a University of Arkansas psychology professor and his former doctoral student. Affect is a term in psychology that describes a broad range of emotional experiences.

"In our study, we wanted to find out if there was a link between the loss of sleep and our emotional response," said Matthew T. Feldner, a professor of psychology in the J. William Fulbright College of Arts and Sciences. "We saw that if a person lost a night of sleep they responded with more emotion to a laboratory 'stressor.' This finding extended previous work that had linked chronic sleep loss to anxiety and mood disorders."

Feldner co-edited Sleep and Affect with Kimberly A. Babson, a health science specialist at the National Center for Post Traumatic Stress Disorder in Menlo Park, California. Babson earned her doctorate in clinical psychology at the University of Arkansas.

Sleep and Affect summarizes research on the interplay of sleep and various components of emotion and affect that are related to mood disorders, anxiety disorders, bipolar disorder and depression.

"One of the themes that emerged across these chapters is that certain components of emotion seem particularly linked to sleep," Feldner said. "What we call 'stressors' tend to be more emotionally arousing for people who haven't slept well, and emotional arousal also appears to interfere with sleep quality."

Babson conducted sleep-and-affect studies at the U of A under a National Institutes of Health research training fellowship. That research spurred her's and Feldner's interest in a book that synthesizes the latest research into the interrelationships between sleep and affect.

"We present this information in a way that will help clinicians both assess for sleep problems and problems related to anxiety or mood, when a patient is seeking treatment for one and maybe not the other," he said. "By improving sleep, we might improve our treatments for anxiety problems."

This book also includes the latest findings in neuroscience related to sleep loss. There appear to be effects of sleep loss on the functioning of the emotional regulation circuit of the brain, Feldner said.

"Some of the neurobiological structures that we think are involved in regulating emotional or affective experiences don't seem to function the same after we lose sleep as they do when we are fully rested," he said.

More information on the book can be found at : https://www.elsevier.com/books/sleep-and-affect/babson/978-0-12-417188-6
http://www.sciencedaily.com/releases/2015/03/150325140212.htm

 

Depression often co-occurs with joint diseases

April 1, 2015
Science Daily/Universität Basel
Depression is one of the leading health risks and affects 350 million people worldwide. Roughly one third of the participants in a recent study who were suffering from depression also suffered from at least one physical disease. This association was evident especially with arthrosis and arthritis that are degenerative and inflammatory diseases of the joints.

Those suffering from depressive symptoms have an increased risk for physical diseases, especially for arthrosis and arthritis. These findings were reported by researchers from the University of Basel and the Ruhr-University Bochum. Their results, based on data from 14,300 people living in Switzerland, have been published in the scientific journal Frontiers in Public Health.

Depression is one of the leading health risks and affects 350 million people worldwide. In Switzerland, around 400,000 people individuals suffer from it each year. Several studies in countries around the globe have shown that depression is associated with an elevated risk for a variety of physical diseases.

However, for Switzerland, a country ranked as one of the wealthiest and with one of the best and most expensive health care systems worldwide, the association between depressive symptoms and physical diseases had yet been unclear.

A research group led by Prof. Gunther Meinlschmidt from the Faculty of Psychology at the University of Basel and the Faculty of Medicine at the Ruhr-University Bochum has now attempted to close this gap. They conducted analyses, using data from the Swiss Health Survey, comprising of 14,348 subjects aged 15 years and older.

Risk for arthrosis and arthritis

The psychologists report that participants with depressive symptoms have a higher risk of suffering from a physical disease. Roughly one third of the participants suffering from depression also suffer from at least one physical disease. This association was evident especially with arthrosis and arthritis that are degenerative and inflammatory diseases of the joints.

More studies are now needed to further scrutinize the association between depression and joint diseases. According to the study, it can be speculated that depressive symptoms result in a lack of interest in physical activity, which may then lead to joint diseases. However, it could also be the other way around: People with joint diseases may be impaired in their daily activities negatively affecting their mental health and ultimately resulting in depressive symptoms. Or: Joint diseases are often caused by inflammatory processes, which have also been speculated for certain types of depressive disorders. Therefore, inflammatory processes may represent the link between depressive symptoms and physical diseases.

Improving health care

"A better understanding of the association between depressive symptoms and physical diseases in Switzerland is the basis for a better health care provision for people suffering from mental disorders as well as physical diseases," says Gunther Meinlschmidt, author of the study. In addition, these findings are also important for health care policy, for example by improving the precision of future estimates of societal burden and costs related to depression.
http://www.sciencedaily.com/releases/2015/04/150401093434.htm

 

Alcohol dependency and early death

April 2, 2015
Science Daily/Universität Bonn
The mortality of alcohol dependent patients in general hospitals is many times higher than that of patients without alcohol dependency. In addition, they die about 7.6 years earlier on average than hospital patients without a history of alcohol addiction. This is what scientists discovered using patient data from various general hospitals in Manchester (England).

"How can I get hold of some alcohol?" Addicts' thoughts increasingly focus on this question. As the compulsive drinking behavior increases, other interests are ignored. Typically, people affected tend to deny their addiction and suffer from withdrawal symptoms and the habituation to alcohol consumption increases. Moreover, alcoholism leads to changes in personality as well as to family and workplace problems.

"Mental problems as well as significant physical health impairments are associated with alcohol addiction," says Dr. Dieter Schoepf from the Department of Psychiatry and Psychotherapy of the University of Bonn Hospital. "Alcoholics who were treated in British general hospitals for health problems die an average of 7.6 years earlier than non-alcohol dependent patients; this is due to the interaction of several concomitant physical illnesses," reports the scientist. For the study, Dr. Schoepf and Prof. Dr. Reinhard Heun from the Royal Derby Hospital in England evaluated patient data from seven general hospitals in Manchester.

This is a long-term observational study: The data extend over a 12.5-year period. Using these data, the scientists analyzed comorbid physical illnesses of 23,371 hospital patients with alcohol dependence and compared them with those of a control group of 233,710 randomly selected patients without alcoholism. Prof. Heun summarized the result: "During the observation period, approximately one out of five hospital patients with alcoholism died in one of the hospitals, while only one out of twelve patients in the control group died."

27 concomitant illnesses occur more frequently with alcohol addiction

A total of 27 physical illnesses occur more often in patients with alcohol addiction: the liver, the pancreas, the airways, the gastrointestinal tract and the nervous system. In contrast to this, heart attacks, cardiovascular disease and cataracts, for instance, occurred less frequently in patients with alcoholism than in the control group. "Patients with addiction problems are often admitted to hospitals as emergency cases. At the time of diagnosis, priority is then given to the acute symptoms -- this may contribute to the fact that not all physical illnesses are recorded," suspects Dr. Schoepf. Reduced pain sensations and perception disorders of addicted persons can also cause certain conditions to not be detected by doctors.

The study is unique in this form, the scientists emphasized. The large number of patients included and the comprehensive control group enabled a highly sophisticated assessment. The long observation period, which is unusual for such investigations, also made it possible to also record illnesses for which symptoms develop only gradually. The fact that the investigation was performed with data from Great Britain is mainly related to the easier access to the necessary information in England. "The results indeed relate to general hospitals in Manchester, however they are representative because of the large numbers of random samples and can therefore be transferred to other general hospitals in other countries," says Dr. Schoepf.

Researchers call for screening and the administration of therapies early on

From the scientists' standpoint, the elevated mortality of patients with alcohol dependence in general hospitals makes it clear that addiction as a major cause of the multiple physical consequences must be treated at a significantly earlier stage. "Through diligent screening and early treatment of concomitant mental and physical illnesses, it should be possible to significantly increase the life expectancy of alcoholic patients," says Prof. Heun.
http://www.sciencedaily.com/releases/2015/04/150402092057.htm

 

A grateful heart is a healthier heart

April 9, 2015
Science Daily/American Psychological Association (APA)
Recognizing and giving thanks for the positive aspects of life can result in improved mental, and ultimately physical, health in patients with asymptomatic heart failure, according to new research.

"We found that more gratitude in these patients was associated with better mood, better sleep, less fatigue and lower levels of inflammatory biomarkers related to cardiac health," said lead author Paul J. Mills, PhD, professor of family medicine and public health at the University of California, San Diego. The study was published in the journal Spirituality in Clinical Practice.

Gratitude is part of a wider outlook on life that involves noticing and appreciating the positive aspects of life. It can be attributed to an external source (e.g., a pet), another person or a non-human (e.g., God). It is also commonly an aspect of spirituality, said Mills. Because previous research has shown that people who considered themselves more spiritual had greater overall well-being, including physical health, Mills and his colleagues examined the role of both spirituality and gratitude on potential health markers in patients.

The study involved 186 men and women who had been diagnosed with asymptomatic (Stage B) heart failure for at least three months. Stage B consists of patients who have developed structural heart disease (e.g., have had a heart attack that damaged the heart) but do not show symptoms of heart failure (e.g., shortness of breath or fatigue). This stage is an important therapeutic window for halting disease progression and improving quality of life since Stage B patients are at high risk of progressing to symptomatic (Stage C) heart failure, where risk of death is five times higher, according to Mills.

Using standard psychological tests, the researchers obtained scores for gratitude and spiritual well-being. They then compared those scores with the patients' scores for depressive symptom severity, sleep quality, fatigue, self-efficacy (belief in one's ability to deal with a situation) and inflammatory markers. They found higher gratitude scores were associated with better mood, higher quality sleep, more self-efficacy and less inflammation. Inflammation can often worsen heart failure.

What surprised the researchers about the findings, though, was that gratitude fully or partially accounted for the beneficial effects of spiritual well-being.

"We found that spiritual well-being was associated with better mood and sleep, but it was the gratitude aspect of spirituality that accounted for those effects, not spirituality per se," said Mills.

To further test their findings, the researchers asked some of the patients to write down three things for which they were thankful most days of the week for eight weeks. Both groups continued to receive regular clinical care during that time.

"We found that those patients who kept gratitude journals for those eight weeks showed reductions in circulating levels of several important inflammatory biomarkers, as well as an increase in heart rate variability while they wrote. Improved heart rate variability is considered a measure of reduced cardiac risk," said Mills.

"It seems that a more grateful heart is indeed a more healthy heart, and that gratitude journaling is an easy way to support cardiac health."
http://www.sciencedaily.com/releases/2015/04/150409093940.htm

 

Impulsive, angry personalities more prone to aggressive driving, accidents

April 28, 2015
Science Daily/Society for Risk Analysis (SRA)
Drivers with impulsive, angry personality characteristics are more likely than other drivers to engage in the kind of belligerent driving that potentially leads to accidents, a new study confirms. These conclusions could be used in designing more effective traffic safety publicity campaigns, authors say.

Past research has suggested that people with impulsive, angry personality traits run a higher risk of engaging in aggressive driving behavior than people without those characteristics, and a new study for the first time confirms those earlier findings. The new research -- which contributes to understanding the significant problem of belligerent driving -- could be used in designing traffic safety campaigns that more effectively train aggressive drivers to alter their behavior, according to the researchers.

Drivers who are readily angered by slower drivers, detours and similar traffic disruptions could be taught to become more aware of their responses and modify them to reduce accident risks, according to the authors. For example, they could be taught to be more mindful of the traffic conditions likely to trigger their anger and to focus on other less aggravating traffic factors. The new study, "Trait predictors of aggression and crash-related behaviors across drivers from the United Kingdom and the Irish Republic" -- by Amanda N. Stephens of the Accident Research Centre, Monash University, Australia, and Mark J. M. Sullman of Cranfield University, United Kingdom -- recently appeared in the online version of Risk Analysis, a publication of the Society for Risk Analysis.

For the new study, a total of 268 male and 281 female fully licensed drivers between the ages of 18 and 75 years voluntarily completed an online questionnaire. The questionnaire was based on well-established systems for measuring traits, such as the Driving Anger Expression Inventory and the Road Rage Questionnaire, which include questions about shouting or swearing at another driver, threatening to hurt another driver, intentionally damaging another vehicle and intentionally hurting another driver.

The authors state that their study's aim was to test a proposed model of driver crash-related behaviors and compare how the model fit with data for drivers in the United Kingdom and Republic of Ireland. According to the model, the personality traits of boredom proneness, impulsiveness and sensation seeking, coupled with driving anger, would predict aggressive driving. Such driving would, in turn, "be a reliable contributor toward crash-related conditions, including near-misses, slips of attention (loss of control of the vehicle and loss of concentration) and moving violations," according to the authors. Their study confirmed the model, "with anger and impulsivity being significant predictors of aggressive expression and this in turn predicting subsequent crash-related behavior." The findings held for both Ireland and the United Kingdom.

Although the new study to some extent replicates previous research, the results make a novel contribution to the broader field because the study used a sample of drivers from the general community, whereas previous research used American university students. Until now, the generalizability of the university results had not been assessed. Drivers in the current study were older and more diverse. In addition, the new study is the first to provide information on self-reported aggression of drivers in the Republic of Ireland and is also the first to support the proposed relationship between impulsivity and driving anger with more than correlational analysis, which provides only limited information about the relationships between variables.
http://www.sciencedaily.com/releases/2015/04/150428105643.htm

 

Locating the brain's SAD center

May 7, 2015
Science Daily/Vanderbilt University
Biologists have known that variations in the amount of sunlight a person receives and her or his circadian clock play a role in the disorder. They have also proposed that the neurotransmitters serotonin and melatonin may be involved. However, they have not yet identified the underlying neurobiological mechanisms responsible. Biologists have now localized the seasonal light cycle effects that drive seasonal affective disorder to a small region of the brain called the dorsal raphe nucleus.
http://images.sciencedaily.com/2015/05/150507122659_1_540x360.jpg

If so, you may be one of the 4 to 6 percent of the American public who suffer from seasonal affective disorder (SAD), a type of depression that occurs during the same season each year.

Biologists have known that variations in the amount of sunlight a person receives and her or his circadian clock play a role in the disorder. They have also proposed that the neurotransmitters serotonin and melatonin may be involved. However, they have not yet identified the underlying neurobiological mechanisms responsible.

Now, a team of Vanderbilt biologists has taken a major step toward this goal. In the May 7 issue of the journal Current Biology, they report that they have localized the seasonal light cycle effects that drive SAD to a small region in the mid-brain called the dorsal raphe nucleus in an experiment with mice, a common "animal model" for studying depression in humans.

In both mice and humans, the dorsal raphe nucleus is an area where many of the specialized neurons that control serotonin levels throughout the brain are located. Because high concentrations of serotonin are associated with feelings of well-being and happiness while low levels are linked to depression, it plays a major role in regulating an individual's mood. Their study also found that the day/night cycle in which individuals are born can have a long-lasting effect on the activity level of the neurons in this region.

"We got the idea for the study from a report by Viennese psychiatrists which found a season of birth correlation in SAD patients," said the study's lead author, graduate student Noah Green.

The biologists decided to concentrate their investigation on the dorsal raphe nucleus because prior studies had shown that it is linked to the brain's master biological clock and it also responds to melatonin, a hormone that is involved in the regulation of a number of related physiological functions, including sleep, blood pressure and seasonal reproduction.

To test the effect of seasonal light cycles, they divided mice into three groups. One group was born and raised in an environment with a summer-like light cycle of 16 hours of light and eight hours of dark. The second group was born and raised with a cycle of 12 hours of light and 12 hours of dark, like spring and fall. The third group was born and raised in a winter-like light cycle with eight hours of light and 16 hours of dark. Other than the light cycle the environments were identical.

Scientists have developed a number of tests to determine whether mice are depressed or, more precisely, exhibit depression-like behavior. For example, one of these is a forced swim test, where the researchers put a mouse in a pool of water and measure how much time it spends struggling to get out and how much time it spends floating passively. They argue that a depressed mouse will spend less time struggling than a normal mouse. (Mice float so they aren't harmed when they stop paddling.)

Administering several of these tests, the Vanderbilt researchers found that the summer-light-cycle mice exhibited lower levels of depression-like behavior than their spring/fall- or winter-light-cycle counterparts.

When the biologists examined the brains of individuals from the three groups, they found a story consistent with the behavioral testing. They found that serotonergic neurons fire faster in the summer-light-cycle mice and they had elevated levels of serotonin and the neurotransmitter norepinephrine, which is known to excite serotonergic neurons.

"Before, we thought serotonin was probably involved. Now we know that serotonergic neurons are definitely involved," said Vanderbilt's Stevenson Chair in Biological Sciences Douglas McMahon, who supervised the study.

Intriguingly, when mice born in summer light cycles were switched to winter light cycles the increased firing of serotonin neurons persisted for several months, into adulthood for the mice.

"This showed that early life seasonal photoperiods can have enduring effects on the serotonin neurons. If such an effect occurs in humans, and is long-lasting, it could contribute to the season of birth modulation of SAD risk," said McMahon.

The researchers also had an opportunity to test the role of melatonin. Normally, the hormone affects the serotonergic neurons in the raphe nucleus by binding to a special structure on the neurons' surface called melatonin receptor 1.

So the researchers got a strain of genetically engineered mice with melatonin receptor 1 "knocked out." Although the pineal glands in these mice worked normally, their serotonergic neurons couldn't respond to the melatonin because they lacked the proper receptors.

When they raised the knock-out mice in the three different photoperiods, the researchers found that the seasonal effect disappeared.
http://www.sciencedaily.com/releases/2015/05/150507122659.htm

 

Sleep loss impedes decision making in crisis

May 7, 2015
Science Daily/Washington State University
The difference between life and death in the operating room, on the battlefield or during a police shootout often comes down to the ability to adapt to the unexpected. Sleep deprivation may make it difficult to do so, according to a study that for the first time created a laboratory experiment that simulates how sleep loss affects critical aspects of decision making in high-stakes, real-world situations.
http://images.sciencedaily.com/2015/05/150507165432_1_540x360.jpg

For the first time, WSU researchers created a laboratory experiment that simulates how sleep loss affects critical aspects of decision making in high-stakes, real-world situations. Their results provide a new understanding of how going without sleep for long periods can lead doctors, first responders, military personnel and others in a crisis situation to make catastrophic decisions.

Overcoming challenge of lab research

Recent history is full of examples of the sometimes devastating consequences of people operating without enough sleep.

Investigations into the Chernobyl nuclear power plant meltdown in Ukraine, the grounding of the Exxon Valdez oil tanker and the explosion of the space shuttle Challenger all concluded that sleep-deprived operators played a role in causing the accidents.

A long-standing conundrum for sleep scientists has been creating a controlled lab situation that sufficiently simulates the circumstances leading to severe lapses in real-world judgment. Previous laboratory research consistently showed sleep loss degrades attention, but its effects on demanding tests of cognition like decision making appeared to be relatively small.

"So there has been a disconnect between decision making in the lab where the effects of sleep loss appeared to be minimal and decision making in the real world where sleep loss can lead to big problems," said Paul Whitney, WSU associate dean and professor of psychology. "Our goal was to bridge the gap and capture the essential elements of real-world decision making in a laboratory experiment."

Adapting to feedback crucial

In a natural context, decision making is a dynamic process that requires a person to learn what is going on nearby as a result of his or her actions and changing circumstances. A surgeon, for instance, might notice a change in a patient's vital signs midway through a procedure. The surgeon can then use this feedback decide a better course of action.

"A novel aspect of this study was using a simple laboratory task that captures the essential aspect of real-world decision making of adapting to new information in a changing situation," said John Hinson, professor of psychology. "Prior studies of sleep loss and decision making have not realized how important adapting to changing circumstances is in determining when sleep loss will lead to decision making failures."

Whitney, Hinson and Hans Van Dongen, director of the WSU Sleep and Performance Research Center at WSU Spokane, along with Melinda Jackson, now of the RMIT University, Victoria, Australia, recruited 26 healthy adults to take part in their study conducted at the Spokane sleep center.

Thirteen of the participants were randomly selected to go 62 hours without sleep two days into the study while the other half of the group was allowed to rest. For six days and nights, the participants lived in a hotel-like laboratory where they performed a specially designed reversal learning task to test their ability to use feedback to guide future decisions.

Mid-study switch confounds sleep deprived

In the task, subjects were shown a series of numbers that, unknown to them, were pre-assigned to have either a "go" (response) or "no go" (non-response) value. They had less than a second to decide whether or not to respond to each number shown.

Every time they correctly identified a number with a "go" value, they received a fictitious monetary reward. Errors resulted in a loss.

After a while, both the sleep-deprived group and the controls started to catch on and selected the right numbers. Then the tricky part came. The researchers reversed the contingencies so that participants had to withhold a response to the "go" numbers and respond to the "no go" numbers.

The switch confounded the sleep deprived participants. Even after being shown 40 numbers with reversed contingencies, they had almost zero success. On the other hand, the rested participants would catch on to the switch within 8-16 numbers.

Implications of sleep-loss risk

The data show that no matter how hard a person wants to make the right choice, sleep loss does something to the brain that simply prevents it from effectively using feedback. The study provides a new tool for investigating how sleep deprivation produces decision errors in real-life situations where information emerges over time.

"People in high-stakes environments are held accountable for their actions when they are fatigued just like everyone else," Van Dongen said. "However, we now know that when someone is sleep-deprived their brain simply can't process feedback from their actions and changing circumstances.

"Our findings tell us that putting sleep-deprived people in perilous environments is an inherently risky business and raises a number of medical, legal and financial implications," he said.
http://www.sciencedaily.com/releases/2015/05/150507165432.htm

 

Eat dark chocolate to beat the midday slump?

May 8, 2015
Science Daily/Northern Arizona University
An EEG study shows chocolate can increase brain characteristics of attention and significantly affect blood pressure levels. Historically, chocolate has been recognized as a vasodilator, meaning that it widens blood vessels and lowers blood pressure in the long run, but chocolate also contains some powerful stimulants. Researchers wanted to investigate if people who consume chocolate would see an immediate stimulant effect.

http://images.sciencedaily.com/2015/05/150508140302_1_540x360.jpg
"Chocolate is indeed a stimulant and it activates the brain in a really special way," said Stevens, a professor of psychological sciences at NAU. "It can increase brain characteristics of attention, and it also significantly affects blood pressure levels."

The study, published in the journal NeuroRegulation and sponsored by the Hershey Company, is the first to examine the acute effects of chocolate on attentional characteristics of the brain and the first-ever study of chocolate consumption performed using electroencephalography, or EEG technology. EEG studies take images of the brain while it is performing a cognitive task and measure the brain activity.

Historically, chocolate has been recognized as a vasodilator, meaning that it widens blood vessels and lowers blood pressure in the long run, but chocolate also contains some powerful stimulants. Stevens said his team wanted to investigate if people who consume chocolate would see an immediate stimulant effect.

Stevens and his colleagues in the Department of Psychological Sciences performed the EEG study with 122 participants between the ages of 18 and 25 years old. The researchers examined the EEG levels and blood pressure effects of consuming a 60 percent cacao confection compared with five control conditions.

Michelle Montopoli, an NAU alumna and student at the time of the study, led the EEG testing phase which included measuring serving sizes of the samples based on participant weight and packaging them so the participants were blind to what they were tasting. Constance Smith, professor of psychological sciences, assisted with the physiological analyses.

The results for the participants who consumed the 60 percent cacao chocolate showed that the brain was more alert and attentive after consumption. Their blood pressure also increased for a short time.

"A lot of us in the afternoon get a little fuzzy and can't pay attention, particularly students, so we could have a higher cacao content chocolate bar and it would increase attention," Stevens said. He added that a regular chocolate bar with high sugar and milk content won't be as good, it's the high-cacao content chocolate that can be found from most manufacturers that will have these effects.

The most interesting results came from one of the control conditions, a 60 percent cacao chocolate which included L-theanine, an amino acid found in green tea that acts as a relaxant. This combination hasn't been introduced to the market yet, so you won't find it on the candy aisle. But it is of interest to Hershey and the researchers.

"L-theanine is a really fascinating product that lowers blood pressure and produces what we call alpha waves in the brain that are very calm and peaceful," Stevens said. "We thought that if chocolate acutely elevates blood pressure, and L-theanine lowers blood pressure, then maybe the L-theanine would counteract the short-term hypertensive effects of chocolate."

For participants who consumed the high-cacao content chocolate with L-theanine, researchers recorded an immediate drop in blood pressure. "It's remarkable. The potential here is for a heart healthy chocolate confection that contains a high level of cacao with L-theanine that is good for your heart, lowers blood pressure and helps you pay attention," Stevens said.

Stevens hopes the results of this study will encourage manufacturers to investigate further and consider the health benefits of developing a chocolate bar made with high-cacao content and L-theanine.

"People don't generally eat chocolate and think it's going to be healthy for them," Stevens said. He added that there is a possibility the millions of hypertension patients in the country could eat a bar of this heart healthy chocolate every afternoon and their blood pressure would drop into the normal range, and they would be more alert and attentive.
http://www.sciencedaily.com/releases/2015/05/150508140302.htm

 

Brain inflammation triggered by chronic pain to anxiety and depression

June 9, 2015
Science Daily/University of California - Irvine
Brain inflammation caused by chronic nerve pain alters activity in regions that regulate mood and motivation, suggesting for the first time that a direct biophysical link exists between long-term pain and the depression, anxiety and substance abuse seen in more than half of these patients, researchers report.

This breakthrough finding also points to new approaches for treating chronic pain, which is second only to bipolar disorder among illness-related causes of suicide. About a quarter of Americans suffer from chronic pain, making it the most common form of enduring illness for those under the age of 60. The Institute of Medicine estimates that this costs our society more than $635 billion per year.

In work with rodents, Catherine Cahill, associate professor of anesthesiology & perioperative care at UCI, Christopher Evans of UCLA's Brain Research Institute, and colleagues discovered that pain-derived brain inflammation causes the accelerated growth and activation of immune cells called microglia. These cells trigger chemical signals within neurons that restrict the release of dopamine, a neurotransmitter that helps control the brain's reward and pleasure centers.

The study also reveals why opioid drugs such as morphine can be ineffective against chronic pain. Morphine and its derivatives normally stimulate the release of dopamine. But in research on mice and rats in chronic pain, Cahill and her colleagues learned that these drugs failed to stimulate a dopamine response, resulting in impaired reward-motivated behavior.
Treating these animals in chronic pain with a drug that inhibits microglial activation restored dopamine release and reward-motivated behavior, Cahill said.

'For over 20 years, scientists have been trying to unlock the mechanisms at work that connect opioid use, pain relief, depression and addiction,' she added. 'Our findings represent a paradigm shift which has broad implications that are not restricted to the problem of pain and may translate to other disorders.'

The results of the five-year study appear online in the Journal of Neuroscience.

Next, Cahill and her team aim to establish that pain-derived changes in human brain circuitry can account for mood disorders. 'We have a drug compound that has the potential to normalize reward-like behavior,' she said, 'and subsequent clinical research could then employ imaging studies to identify how the same disruption in reward circuitry found in rodents occurs in chronic pain patients.'
http://www.sciencedaily.com/releases/2015/06/150609213337.htm

 

Poor sleep associated with increased risk of heart attack, stroke

Poor sleep should be considered a risk factor for cardiovascular disease along with smoking, lack of exercise and poor diet
June 15, 2015
Science Daily/European Society of Cardiology
Poor sleep is associated with increased risk of heart attack and stroke, according to results from a recent study. The study included a representative sample of 657 men aged 25 to 64 years with no history of heart attack, stroke or diabetes. In terms of sleep quality, very bad, bad or poor ratings were considered a sleeping disorder in the study. Cases of myocardial infarction and stroke were recorded over the next 14 years.

Professor Gafarov said: "Mortality from cardiovascular diseases accounts for nearly 50% of the total mortality among the population. Nearly 80% of deaths from cardiovascular disease are due to myocardial infarction (heart attack) and stroke. It means that today we are talking about an epidemic of cardiovascular disease. It is therefore necessary to engage in intensive prevention of risk factors leading to the development of cardiovascular diseases."

He continued: "Sleep disorders are very closely related to the presence of cardiovascular diseases. However, until now there has not been a population based cohort study examining the impact of sleep disorders on the development of a heart attack or stroke."

The research was part of the World Health Organization (WHO) programme "MONICA" (Multinational Monitoring of trends and determinants in Cardiovascular disease) and the "MONICA-psychosocial" substudy. It investigated the relationship between sleep disturbances and the risk of developing a heart attack or stroke in the long-term.

The study included a representative sample of 657 men aged 25 to 64 years with no history of heart attack, stroke or diabetes in Novosibirsk, Russia. Sleep quality was assessed when the study began in 1994 using the Jenkins Sleep Scale. Very bad, bad or poor ratings were considered a sleeping disorder. Cases of myocardial infarction and stroke were recorded over the next 14 years.

During the study period, nearly two-thirds (63%) of participants who had a heart attack also had a sleeping disorder. Sleeping disorders are closely associated with negative affective states (anxiety, depression, hostility, vital exhaustion). They are connected with the social gradient and are a manifestation of social stress in the population.

Men with a sleeping disorder had a risk of myocardial infarction that was 2 to 2.6 times higher and a stroke risk that was 1.5 to 4 times higher than those without a sleeping disorder between 5 and 14 years of follow up.

Professor Gafarov said: "Sleeping disorders were associated with greatly increased incidents of both heart attack and stroke. We also found that the rates of heart attack and stroke in men with sleeping disorders were related to the social gradient, with the highest incidents in those who were widowed or divorced, had not finished secondary school, and were engaged in medium to heavy manual labour."

He added: "Sleep is not a trivial issue. In our study it was associated with double the risk of a heart attack and up to four times the risk of stroke. Poor sleep should be considered a modifiable risk factor for cardiovascular disease along with smoking, lack of exercise and poor diet. Guidelines should add sleep as a risk factor to recommendations for preventing cardiovascular disease."

Professor Gafarov continued: "For most people, good quality sleep is 7 to 8 hours of rest each night. People who are not sleeping well should speak to their doctor. Our previous research showed that sleeping disorders are very closely connected with depression, anxiety and hostility, so speaking with a psychologist may also help."
http://www.sciencedaily.com/releases/2015/06/150615094255.htm

 

Public divided on heart benefits from alcohol consumption

Researchers find those believing alcohol as 'heart healthy' drink much more than counterparts
June 16, 2015
Science Daily/University of California - San Francisco
In one of the first published studies using data from the Health eHeart Study, researchers have found that people are divided on the cardiovascular benefits of alcohol consumption. And, those who do perceive alcohol as 'heart healthy' drink substantially more than their counterparts.

"While we often hear about alcohol's effects, this is the first assessment to address how the public might use that information," said senior author Gregory Marcus, MD, MAS, director of clinical research in the UCSF Division of Cardiology.

Alcohol is the most commonly consumed U.S drug, according to the study researchers. While the harms of alcohol abuse related to physical and mental health have been established, there is debate regarding the cardiovascular health effects of moderate consumption. The researchers note that while few, if any, rigorous controlled trials have been conducted to determine alcohol's potential heart benefits, the media frequently portray alcohol as "heart healthy."

To determine people's perceptions of the cardiovascular benefits of alcohol, the source of those perceptions and how perceptions may influence behavior, Marcus and his colleagues conducted a cross-sectional analysis of data collected from participants enrolled in the Health eHeart Study between March 8, 2013, and Sept. 29, 2014.

The innovative Health eHeart Study harnesses the power of online and mobile technology to gather cardiovascular data from study participants through devices such as smartphone apps, ECG smartphone cases and portable blood pressure cuffs. With a goal of one million participants, Health eHeart already has more than 20,000 people enrolled from around the world, with no study centers other than the one at UCSF.

Of the 5,582 Health eHeart Study participants who responded to questions on alcohol at the time of this analysis, 1,707 (30 percent) viewed alcohol as heart healthy, 2,157 (39 percent) viewed alcohol as unhealthy, and 1,718 (31 percent) were unsure. Of those reporting alcohol as heart healthy, 80 percent cited the lay press as a source of their knowledge.

Further, those respondents who perceived alcohol as heart healthy were older, more often women, had higher levels of education and income, and more often resided in the United States. Compared to the rest of the cohort, they consumed, on average, 47 percent more alcohol. A vast majority of them also believe that red wine exclusively is beneficial.

Smokers and those with heart failure were less likely to view alcohol favorably.

"It is particularly interesting to note that those who believe alcohol to be heart healthy actually drink more alcohol," Marcus said. "Whether their belief causes this behavior, or merely justifies it, remains an interesting unknown. Future studies that perhaps assign different types of medical advice regarding alcohol may be very worthwhile and relevant to the great majority of our population -- more than 80 percent of whom drink alcohol."
http://www.sciencedaily.com/releases/2015/06/150616155901.htm

 

Eating 100 g of chocolate daily linked to lowered heart disease and stroke risk

June 15, 2015
Science Daily/BMJ
Eating up to 100 g of chocolate every day is linked to lowered heart disease and stroke risk. The calculations showed that compared with those who ate no chocolate higher intake was linked to an 11% lower risk of cardiovascular disease and a 25% lower risk of associated death.

There doesn't seem to be any evidence for cutting out chocolate to lower the risk of cardiovascular disease, conclude the researchers.

They base their findings on almost 21,000 adults taking part in the EPIC-Norfolk study, which is tracking the impact of diet on the long term health of 25,000 men and women in Norfolk, England, using food frequency and lifestyle questionnaires.

The researchers also carried out a systematic review of the available international published evidence on the links between chocolate and cardiovascular disease, involving almost 158,000 people--including the EPIC study participants.

The EPIC-Norfolk participants (9214 men and 11 737 women) were monitored for an average of almost 12 years, during which time 3013 (14%) people experienced either an episode of fatal or non-fatal coronary heart disease or stroke.

Around one in five (20%) participants said they did not eat any chocolate, but among the others, daily consumption averaged 7 g, with some eating up to 100 g.

Higher levels of consumption were associated with younger age and lower weight (BMI), waist: hip ratio, systolic blood pressure, inflammatory proteins, diabetes and more regular physical activity --all of which add up to a favourable cardiovascular disease risk profile.

Eating more chocolate was also associated with higher energy intake and a diet containing more fat and carbs and less protein and alcohol.

The calculations showed that compared with those who ate no chocolate higher intake was linked to an 11% lower risk of cardiovascular disease and a 25% lower risk of associated death.

It was also associated with a 9% lower risk of hospital admission or death as a result of coronary heart disease, after taking account of dietary factors.

And among the 16,000 people whose inflammatory protein (CRP) level had been measured, those eating the most chocolate seemed to have an 18% lower risk than those who ate the least.

The highest chocolate intake was similarly associated with a 23% lower risk of stroke, even after taking account of other potential risk factors.

Of nine relevant studies included in the systematic review, five studies each assessed coronary heart disease and stroke outcome, and they found a significantly lower risk of both conditions associated with regular chocolate consumption.

And it was linked to a 25% lower risk of any episode of cardiovascular disease and a 45% lower risk of associated death.

This is an observational study so no definitive conclusions about cause and effect can be drawn. And the researchers point out that food frequency questionnaires do involve a certain amount of recall bias and underestimation of items eaten.

Reverse causation--whereby those with a higher cardiovascular disease risk profile eat less chocolate and foods containing it than those who are healthier--may also help to explain the results, they say.

Nevertheless, they add: "Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events."

And they point out that as milk chocolate, which is considered to be less 'healthy' than dark chocolate, was more frequently eaten by the EPIC-Norfolk participants, the beneficial health effects may extend to this type of chocolate too.

"This may indicate that not only flavonoids, but also other compounds, possibly related to milk constituents, such as calcium and fatty acids, may provide an explanation for the observed association," they suggest.

And they conclude: "There does not appear to be any evidence to say that chocolate should be avoided in those who are concerned about cardiovascular risk."
http://www.sciencedaily.com/releases/2015/06/150615191518.htm

 

Lack of sleep affects long-term health

June 16, 2015
Science Daily/University of Copenhagen, The Faculty of Health and Medical Sciences
Maintaining a good night's sleep is important for our future health, partly because of how it affects lifestyle factors. Previous population based studies have not provided sufficient information on the timing of changes in both sleep and lifestyle to tease out cause and effect relations of this highly intertwined relationship.

"This study shows that sleep affects our ability to maintain a healthy lifestyle, and when sleep deteriorates we are more likely to make unhealthy lifestyle changes," says Postdoc Alice Jessie Clark from the Department of Public Health, University of Copenhagen. The research has been published in the International Journal of Epidemiology.

Unhealthy lifestyle changes

The researchers found that maintaining a good night's sleep made it easier to maintain a healthy lifestyle. For example; they found that smokers who maintained a sleeping pattern characterized by normal sleep duration and undisturbed nights were less likely to still be smoking and more likely to have quit smoking four years on, when compared to those who either shortened their average sleep duration or experienced an increase in sleep disturbances.

Overall, similar patterns were also observed in regards to other adverse lifestyle changes, with onset of impaired sleep inflicting a higher risk of uptake of high-risk alcohol consumption (among non-risk consumers), of becoming physically inactive (among the initially physically active), and of becoming overweight or obese.

International collaboration

The research was conducted as an international collaboration between established sleep researchers and epidemiologists from Denmark and Finland, based on more than 35,000 adult Finns who participated in at least three successive waves of this large longitudinal cohort study.

For the study, the researchers made strict inclusion and exclusion criteria to identify eligible participants building on information from three successive waves of the cohort study. This enabled temporal separation between onset of impaired sleep and subsequent changes in lifestyle among participants with a stable lifestyle before experiencing deteriorations in sleep.

By way of example; in order to determine the effect of onset of disturbed sleep on risk of becoming physically inactive, the researchers followed the group of physically active undisturbed sleepers for four years (from the first to the second wave) to assess exposure status, i.e. onset of disturbed sleep (among those still physically active at the second wave). They then followed the still active participants, some of which now suffered disturbed sleeping patterns, an additional four years (until the third wave) to assess whether the risk of becoming physically inactive differed between persistent normal sleepers and those who had experienced an increase in sleep disturbances.

"Better knowledge of the importance of sleep, not just for biological restitution, but also for making healthy lifestyle decisions, may help people make informed decisions about prioritizing how to spend the night -- caching up on work emails, surfing social media or going to bed and ensuring a good night's sleep," concludes Clark.
http://www.sciencedaily.com/releases/2015/06/150616072357.htm

 

Increased anxiety associated with sitting down

June 19, 2015
Science Daily/BioMed Central
Low-energy activities that involve sitting down are associated with an increased risk of anxiety, according to new research. These activities, which include watching TV, working at a computer or playing electronic games, are called sedentary behavior.

Many studies have shown that sedentary behavior is associated with physical health problems like obesity, heart disease, type 2 diabetes and osteoporosis. However, there has been little research into the link between sedentary behavior and mental health. This is the first systematic review to examine the relationship between anxiety and sedentary behavior.

Anxiety is a mental health illness that affects more than 27 million people worldwide. It is a debilitating illness that can result in people worrying excessively and can prevent people carrying out their daily life. It can also result in physical symptoms, which amongst others includes pounding heartbeat, difficulty breathing, tense muscles, and headaches.

Megan Teychenne, lead researcher and lecturer at Deakin University's Centre for Physical Activity and Nutrition Research (C-PAN) in Australia, said: "Anecdotally -- we are seeing an increase in anxiety symptoms in our modern society, which seems to parallel the increase in sedentary behavior. Thus, we were interested to see whether these two factors were in fact linked. Also, since research has shown positive associations between sedentary behavior and depressive symptoms, this was another foundation for further investigating the link between sedentary behavior and anxiety symptoms."

C-PAN researchers analyzed the results of nine studies that specifically examined the association between sedentary behavior and anxiety. The studies varied in what they classified as sedentary behavior from television viewing/computer use to total sitting time, which included sitting while watching television, sitting while on transport and work-related sitting. Two of the studies included children/adolescents while the remaining seven included adults.

It was found in five of the nine studies that an increase in sedentary behavior was associated with an increased risk of anxiety. In four of the studies it was found that total sitting time was associated with increased risk of anxiety. The evidence about screen time (TV and computer use) was less strong but one study did find that 36% of high school students that had more than 2 hours of screen time were more like to experience anxiety compared to those who had less than 2 hours.

The C-PAN team suggests the link between sedentary behavior and anxiety could be due to disturbances in sleep patterns, social withdrawal theory and poor metabolic health. Social withdrawal theory proposes that prolonged sedentary behavior, such as television viewing, can lead to withdrawal from social relationships, which has been linked to increased anxiety. As most of the studies included in this systematic-review were cross-sectional the researchers say more follow-up work studies are required to confirm whether or not anxiety is caused by sedentary behavior.

Megan Teychenne said: "It is important that we understand the behavioral factors that may be linked to anxiety -- in order to be able to develop evidence-based strategies in preventing/managing this illness. Our research showed that evidence is available to suggest a positive association between sitting time and anxiety symptoms -- however, the direction of this relationship still needs to be determined through longitudinal and interventional studies."
http://www.sciencedaily.com/releases/2015/06/150619085534.htm 

 

Feeling impulsive or frustrated? Take a nap

June 29, 2015
Science Daily/University of Michigan
It's becoming increasingly common for people, especially adults, to not sleep an entire night. This can negatively impair a person's attention span and memory, as well as contribute to fatigue. Now researchers report that taking a nap may be an effective strategy to counteract impulsive behavior and to boost tolerance for frustration.

It's becoming increasingly common for people, especially adults, to not sleep an entire night. This can negatively impair a person's attention span and memory, as well as contribute to fatigue.

U-M researchers examined how a brief nap affected adults' emotional control. The study's 40 participants, ages 18-50, maintained a consistent sleep schedule for three nights prior to the test.

In a laboratory, participants completed tasks on computers and answered questions about sleepiness, mood and impulsivity. They were randomly assigned to a 60-minute nap opportunity or no-nap period that involved watching a nature video. Research assistants monitored the participants, who later completed those questionnaires and tasks again.

Those who napped spent more time trying to solve a task than the non-nappers who were less willing to endure frustration in order to complete it. In addition, nappers reported feeling less impulsive.

Combined with previous research demonstrating the negative effects of sleep deprivation, results from the U-M study indicate that staying awake for an extended period of time hinders people from controlling negative emotional responses, said Jennifer Goldschmied, the study's lead author.

"Our results suggest that napping may be a beneficial intervention for individuals who may be required to remain awake for long periods of time by enhancing the ability to persevere through difficult or frustrating tasks," said Goldschmied, a doctoral student in the Department of Psychology.

Napping may also be a cost-efficient and easy strategy to increase workplace safety, the researchers said. Employers who add nap pods in the workplace or offer extended break time may find their employees more productive.
http://www.sciencedaily.com/releases/2015/06/150629111059.htm

 

How your brain knows it's summer

June 29, 2015
Science Daily/RIKEN
Researchers have discovered a key mechanism underlying how animals keep track of the seasons. The study shows how circadian clock machinery in the brain encodes seasonal changes in daylight duration through GABA activity along with changes in the amount of chloride located inside certain neurons.
http://images.sciencedaily.com/2015/06/150629152435_1_540x360.jpg

Seasonal time keeping is important for animals as well as people, and recent studies indicate that it is accomplished by the same part of the brain that governs our daily circadian rhythms. This brain area, called the suprachiasmatic nucleus (SCN), cyclically expresses certain "clock" genes during a 24-hour period, but not all of the neurons march to the same beat. Two regions in the SCN are slightly out of phase, and as day length increases, so does the phase gap between them.

To understand how this happens, the researchers first measured expression levels of the clock gene Bmal1 in explanted dorsal and ventral SCNs of mice that had been living in long-day or short-day light cycles. As expected, cyclical BMAL1 levels in dorsal and ventral regions from the long-day group were out of phase, while those from the short-day group were synchronized. Modeling analysis predicted that coupling between the two regions is not a two-way street, and that this asymmetry causes the dorsal region to become out of phase when daylight increases.

The research team found that the neurotransmitter GABA plays an important role in this process. In most cases, GABA inhibits the activity of neurons. However, some SCN neurons are actually excited by GABA. Lead author Jihwan Myung explains, "GABA becomes excitatory when chloride levels inside neurons are high. We suspected that changes in GABA function across the SCN could represent the repulsive force that pushes these two clusters of neurons out of phase."

When the researchers blocked GABA activity, the large phase gap seen in the long-day group disappeared and the cycles of Bmal1 levels came to resemble those of the short-day group, which was unaffected. This suggested to the team that GABA has a special effect on the dorsal SCN.

To test this hypothesis, they measured expression levels of two other genes -- Nkcc1 and Kcc2 -- that are responsible for importing and exporting chloride. They found that in long-day SCNs, the expression ratio of the two genes in the dorsal SCN changed so that much more chloride was imported. This made the effect of GABA preferentially excitatory in the dorsal region. Blocking chloride import abolished the phase gap seen in the long-day group, and as predicted by the model, even made SCNs trained on an even 12-hour daylight cycle resemble the short-day group.

"Just like in other animals, our bodies keep track of the seasons," says Myung, "and sudden changes in seasonal day length can cause severe mood disorder in some individuals. Understanding how to adjust our internal seasonal clock could lead to effective ways of helping people whose internal clocks have been disrupted."
http://www.sciencedaily.com/releases/2015/06/150629152435.htm

 

Improving sleep quality has pain control benefits

July 1, 2015
Science Daily/American Pain Society
Sleep disruption appears to be associated with altered pain processing and central sensitization, according to research. For the study, participants with knee pain were recruited from the community with eligibility being age 45 to 85, African American or non-Hispanic white and knee OA based on American College of Rheumatology criteria. Subjects completed sleep questionnaires and experimental pain applications.

In patients with osteoarthritis (OA), more than half experience pain during the night, resulting in sleep disruption, poor sleep quality, sleep fragmentation and frequent shifts between sleep stages. Recent studies have shown that sleep disruption can be a predictor of pain severity. Sleep disruption, therefore, could be associated with increased pain sensitivity and enhanced pain facilitation in addition to reduced pain inhibition in persons with chronic pain.

A team of researchers from Arizona State University, University of Alabama and University of Florida analyzed the relationships of self-reported insomnia severity and maladaptive sleep behaviors with pain sensitivity in persons with knee osteoarthritis (OA). They hypothesized that reports of greater insomnia severity would be associated with lower pain thresholds and inhibition and with greater temporal summation of pain.

For the study, participants with knee pain were recruited from the community with eligibility being age 45 to 85, African American or non-Hispanic white and knee OA based on American College of Rheumatology criteria. Subjects completed sleep questionnaires and experimental pain applications.

Results showed that severity of sleep disruption were associated with altered pain processing, and that sleep interventions for persons with knee OA-related pain might contribute to pain reductions. The authors noted that cognitive-behavioral therapies focused on sleep may have the most significant benefits for improving sleep in patients with insomnia and OA pain.
http://www.sciencedaily.com/releases/2015/07/150701094506.htm

 

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