Crying has its perks
August 24, 2015
Science Daily/Springer
Effect of crying on one's mood
Yes, a good cry indeed might go a long way to make you feel better. These findings were established after a research team videotaped a group of participants while watching emotionally charged films. Afterwards, the participants were asked a few times to reflect on how they felt.
Although humans are the only species able to shed emotional tears, little is known about the function of crying. While some researchers see it as a cry for support, comfort or help, others believe the main role of crying is to relieve emotions. Different types of studies focusing on the latter, however, provide conflicting results. Retrospective self-report studies support claims that crying provides emotional relief and ultimately influences someone's mood for the better. In contrast, laboratory studies using emotional films often show a consistent decrease in mood immediately after an emotional event.
In an effort to understand these discrepant results, Gračanin's team extended methodology used in previous laboratory studies. They examined both the immediate and the delayed effect of crying on mood within a controlled laboratory setting. The two films shown to 60 participants are known to be tearjerkers. Immediately afterwards, the 28 participants who cried and the 32 who didn't shed a tear were asked how they felt. They also had to rate their moods 20 and 90 minutes later.
As expected, the mood of the non-criers was unchanged and unaffected immediately after seeing the films. The mood of the criers, on the other hand, was distinctively low and even took a dip. Within 20 minutes, however, their mood had returned to the level reported before the screening. Finally, after 90 minutes, the criers reported even a better mood than was the case before the films started. Such a mood shift was not tied to the number of times that a person cried during the films.
According to Gračanin, it's this dip and subsequent return of emotions to previous levels that might make criers feel as if they are in a much better mood after they have shed some tears.
However, it seems that criers even experience a general mood increase, but only after a longer period of time.
"After the initial deterioration of mood following crying, it takes some time for the mood not only to recover but also to be lifted above the levels at which it had been before the emotional event," he explains. This pattern is often found in retrospective studies where people are asked to rate their mood levels after having experienced a good cry.
http://www.sciencedaily.com/releases/2015/08/150824101829.htm
The bane of your existence: Smartphones and ‘technostress’
August 26, 2015
Science Daily/Taylor & Francis
If you feel stressed out by your smartphone, it might be down to your personality as well as your phone, a new study suggests.
Writing in the journal Behaviour & Information Technology, Yu-Kang Lee and colleagues explored the relationship between four key personality traits, the types of phones people used and the levels of 'technostress' they experienced.
The first trait they studied was 'locus of control', which the authors defined as 'the extent to which people believe that their actions determine their rewards in life'. As smartphones blur the line between home and work, encourage multi-tasking and constant checking, the authors found them unsurprisingly to be a greater source of technostress than traditional phones. 'This has been called the "helpful-stressful cycle," in which one purchases a smartphone to help manage the workload only to have it induce stress and become the bane of one's existence,' they observe.
The second trait the authors explored was 'social interaction anxiety' (SIA). As people with high SIA are more likely to depend on the internet for social networking, they are also more likely to suffer the negative side effects of excessive use including stress caused by repeated smartphone checking and internet addiction.
The third trait was the 'need for touch', which can be satisfied in many people by constantly fiddling with their smartphone touch screens -- a problem users of traditional phones don't have. However, the fact that touching a smartphone becomes almost compelling is yet another source of technostress for their users.
The final trait, materialism, was the only one that seemed to cause more technostress in users of traditional phones than smartphones. The reason why isn't clear, but the authors suggest that perhaps users of snazzy smartphones have already reached a 'ceiling' in terms of their own material desires and therefore how much stress it can cause them.
So we now know that certain personality traits can make people more prone to suffer technostress, and health professionals may be able to identify and treat people who fall victim to technostress. And finally, this new work can also help individual users: the authors recommend that people with high levels of technostress -- and the 'attendant psychological characteristics' -- reduce their mobile usage, which
http://www.sciencedaily.com/releases/2015/08/150826082152.htm
Midday naps associated with reduced blood pressure and fewer medications
August 29, 2015
Science Daily/European Society of Cardiology
Midday naps are associated with reduced blood pressure levels and prescription of fewer antihypertensive medications, according to new research.
"Although William Blake affirms that it is better to think in the morning, act at noon, eat in the evening and sleep at night, noon sleep seems to have beneficial effects," said Dr Kallistratos. "Two influential UK Prime Ministers were supporters of the midday nap. Winston Churchill said that we must sleep sometime between lunch and dinner while Margaret Thatcher didn't want to be disturbed at around 3:00 pm. According to our study they were right because midday naps seem to lower blood pressure levels and may probably also decrease the number of required antihypertensive medications."
He added: "Μidday sleep is a habit that nowadays is almost a privileged due to a nine to five working culture and intense daily routine. However the real question regarding this habit is: is it only a custom or is it also beneficial?"
The purpose of this prospective study was to assess the effect of midday sleep on blood pressure (BP) levels in hypertensive patients. The study included 386 middle aged patients (200 men and 186 women, average age 61.4 years) with arterial hypertension. The following measurements were performed in all patients: midday sleep time (in minutes), office BP, 24 hour ambulatory BP, pulse wave velocity, lifestyle habits, body mass index (BMI) and a complete echocardiographic evaluation including left atrial size. BP measurements were reported as diastolic and systolic BP.
After adjusting for other factors that could influence BP such as age, gender, BMI, smoking status, salt, alcohol, exercise and coffee, the researchers found that midday sleepers had 5% lower average 24 hour ambulatory systolic BP (6 mmHg) compared to patients who did not sleep at all midday. Their average systolic BP readings were 4% lower when they were awake (5 mmHg) and 6% lower while they slept at night (7 mmHg) than non-midday sleepers.
Dr Kallistratos said: "Although the mean BP decrease seems low, it has to be mentioned that reductions as small as 2 mmHg in systolic blood pressure can reduce the risk of cardiovascular events by up to 10%."
The researchers also found that in midday sleepers pulse wave velocity levels were 11% lower and left atrium diameter was 5% smaller. "These findings suggest that midday sleepers have less damage from high blood pressure in their arteries and heart," said Dr Kallistratos.
The duration of midday sleep was associated with the burden of arterial hypertension. Patients who slept for 60 minutes midday had 4 mmHg lower average 24 hour systolic BP readings and a 2% higher dipping status5 compared to patients who did not sleep midday. Dippers had an average of 17 minutes more midday sleep than non-dippers.
Dr Kallistratos said: "Our study shows that not only is midday sleep associated with lower blood pressure, but longer sleeps are even more beneficial. Midday sleepers had greater dips in blood pressure while sleeping at night which is associated with better health outcomes. We also found that hypertensive patients who slept at noon were under fewer antihypertensive medications compared to those who didn't sleep midday."
He concluded: "We found that midday sleep is associated with lower 24 hour blood pressure, an enhanced fall of BP in night, and less damage to the arteries and the heart. The longer the midday sleep, the lower the systolic BP levels and probably fewer drugs needed to lower BP."
https://www.sciencedaily.com/releases/2015/08/150829123659.htm
Short sleepers are four times more likely to catch a cold
August 31, 2015
Science Daily/University of California - San Francisco
Researchers connect sleep loss to higher rates of illness
A new study led by a sleep researcher supports what parents have been saying for centuries: to avoid getting sick, be sure to get enough sleep.
The team, which included researchers at Carnegie Mellon University and University of Pittsburgh Medical Center, found that people who sleep six hours a night or less are four times more likely to catch a cold when exposed to the virus, compared to those who spend more than seven hours a night in slumber land.
This is the first study to use objective sleep measures to connect people's natural sleep habits and their risk of getting sick, according to Aric Prather, PhD, assistant professor of Psychiatry at UCSF and lead author of the study. The findings add to the growing evidence of the importance of sleep for our health, he said.
"Short sleep was more important than any other factor in predicting subjects' likelihood of catching cold," Prather said. "It didn't matter how old people were, their stress levels, their race, education or income. It didn't matter if they were a smoker. With all those things taken into account, statistically sleep still carried the day."
The study, "Behaviorally assessed sleep and susceptibility to the common cold," appears online and in the September issue of the journal Sleep.
The Centers for Disease Control and Prevention call insufficient sleep a public health epidemic, linking poor sleep with car crashes, industrial disasters and medical errors. According to a 2013 survey by the National Sleep Foundation, one in five Americans gets less than six hours of sleep on the average work night, the worst tally of the six countries surveyed.
Scientists have long known that sleep is important for our health, with poor sleep linked to chronic illnesses, disease susceptibility and even premature death. Prather's previous studies have shown that people who sleep fewer hours are less protected against illness after receiving a vaccine. Other studies have confirmed that sleep is among the factors that regulate T-cell levels.
To learn how sleep affects the body's response to a real infection, Prather collaborated with Carnegie Mellon psychologist Sheldon Cohen, PhD, the study's senior author, who has spent years exploring psychological and social factors contributing to illness. Cohen's group gives volunteers the common cold virus to safely test how these various factors affect the body's ability to fight off disease. For this paper, Prather approached Cohen about investigating sleep and cold susceptibility using data collected in his lab's recent study, in which participants wore sensors to get objective, sleep measurements.
"We had worked with Dr. Prather before and were excited about the opportunity to have an expert in the effects of sleep on health take the lead in addressing this important question," Cohen said.
Researchers recruited 164 volunteers from the Pittsburgh, PA, area between 2007 and 2011. The recruits underwent two months of health screenings, interviews and questionnaires to establish baselines for factors such as stress, temperament, and alcohol and cigarette use. The researchers also measured participants' normal sleep habits a week prior to administering the cold virus, using a watch-like sensor that measured the quality of sleep throughout the night.
The researchers then sequestered volunteers in a hotel, administered the cold virus via nasal drops and monitored them for a week, collecting daily mucus samples to see if the virus had taken hold.
They found that subjects who had slept less than six hours a night the week before were 4.2 times more likely to catch the cold compared to those who got more than seven hours of sleep, and those who slept less than five hours were 4.5 times more likely.
"It goes beyond feeling groggy or irritable," Prather said. "Not getting sleep fundamentally affects your physical health."
The study shows the risks of chronic sleep loss better than typical experiments in which researchers artificially deprive subjects of sleep, said Prather, because it is based on subjects' normal sleep behavior. "This could be a typical week for someone during cold season," he said.
The new data add yet another piece of evidence that sleep should be treated as a crucial pillar of public health, along with diet and exercise, the researchers said. But it's still a challenge to convince people to get more sleep.
"In our busy culture, there's still a fair amount of pride about not having to sleep and getting a lot of work done," Prather said. "We need more studies like this to begin to drive home that sleep is a critical piece to our wellbeing."
http://www.sciencedaily.com/releases/2015/08/150831163729.htm
Timing of sleep just as important as quantity
September 1, 2015
Science Daily/Washington State University
Shifting sleep cycle affects immune response, sleep quality
The timing of an animal's sleep can be just as important as how much sleeps it gets, researchers have discovered.
Ilia Karatsoreos, an assistant professor in WSU's Department of Integrative Physiology and Neuroscience, shifted mice from their usual cycle of sleeping and waking and saw that, while they got enough sleep, it was of poorer quality. The animals also had a disrupted immune response, leaving them more open to illness.
Most sleep research focuses on the effects of sleep deprivation or the overall amount of sleep an animal needs. This is generally referred to as sleep's homeostatic process, which is driven by sleepiness or "sleep pressure."
The work by Karatsoreos and his colleagues--published in the journal Brain, Behavior and Immunity--is a rare look into the circadian process, a brain-driven clock that controls the rhythms of various biological processes, from digestion to blood pressure, heart rate to waking and sleeping. The cycle is found in most everything that lives more than 24 hours, including plants and single-celled organisms.
Research into the system has significant implications for modern living, write Karatsoreos and his coauthors, as "disruption of the circadian clock is nearly ubiquitous in our modern society" due to nighttime lighting, shift work, jet lag and even the blue-tinged light emitted by cell phones and tablets.
Typically, sleep researchers have a hard time studying sleep deprivation and the circadian cycle separately, as a change in one usually affects the other. However, Karatsoreos and his colleagues saw their model did not affect an animal's total sleep, giving them a unique look into the effects on the timing of the sleeping-waking cycle.
The researchers used mice whose body clocks run at about 24 hours - much like our own - and housed them in a shorter 20-hour day. This forced their biological clocks out of sync with the light-dark cycle. After four weeks, the researchers injected the mice with lipopolysaccharide, a molecule found in bacteria that can make an animal sick without being contagious.
The researchers saw that the disrupted animals had blunted immune responses in some cases or an overactive response in others, suggesting the altered circadian cycle made them potentially less able to fight illness and more likely to get sick.
"This represents a very clear dysregulation of the system," said Karatsoreos. "The system is not responding in the optimal manner." Over time, he said, this could have serious consequences for an organism's health.
"Just like you have a car that you're running into the ground--things don't work right but you keep driving it until it stops. That's what could happen if you think of disruption going on for years for somebody who's working shift work," he said.
To his surprise, the mice on the 20-hour cycle were getting the same amount of sleep as they did on the 24-hour cycle. But the sleep wasn't as good. The mice woke more often and the pattern of electrical activity in their brains related to restorative sleep was greatly reduced.
http://www.sciencedaily.com/releases/2015/09/150901113425.htm
Feeling blue and seeing blue: Sadness may impair color perception
September 2, 2015
Science Daily/Association for Psychological Science
The world might seem a little grayer than usual when we're down in the dumps and we often talk about 'feeling blue' -- new research suggests that the associations we make between emotion and color go beyond mere metaphor. The results of two studies indicate that feeling sadness may actually change how we perceive color.
http://images.sciencedaily.com/2015/09/150902112006_1_540x360.jpg
The results of two studies indicate that feeling sadness may actually change how we perceive color.
Credit: © Sasipixel / Fotolia
"Our results show that mood and emotion can affect how we see the world around us," says psychology researcher Christopher Thorstenson of the University of Rochester, first author on the research. "Our work advances the study of perception by showing that sadness specifically impairs basic visual processes that are involved in perceiving color."
Previous studies have shown that emotion can influence various visual processes, and some work has even indicated a link between depressed mood and reduced sensitivity to visual contrast. Because contrast sensitivity is a basic visual process involved in color perception, Thorstenson and co-authors Adam Pazda and Andrew Elliot wondered whether there might be a specific link between sadness and our ability to perceive color.
"We were already deeply familiar with how often people use color terms to describe common phenomena, like mood, even when these concepts seem unrelated," says Thorstenson. "We thought that maybe a reason these metaphors emerge was because there really was a connection between mood and perceiving colors in a different way."
In one study, the researchers had 127 undergraduate participants watch an emotional film clip and then complete a visual judgment task. The participants were randomly assigned to watch an animated film clip intended to induce sadness or a standup comedy clip intended to induce amusement. The emotional effects of the two clips had been validated in previous studies and the researchers confirmed that they produced the intended emotions for participants in this study.
After watching the video clip, the participants were then shown 48 consecutive, desaturated color patches and were asked to indicate whether each patch was red, yellow, green, or blue.
The results showed that participants who watched the sadness video clip were less accurate in identifying colors than participants who watched the amusing clip, but only for color patches that were on the blue-yellow axis. They showed no difference in accuracy for colors on the red-green axis.
And a second study with 130 undergrad participants showed the same effect in comparison to a neutral film clip: Participants who watched a sad clip were less accurate in identifying colors on the blue-yellow spectrum than those who watched a neutral screensaver. The findings suggest that sadness is specifically responsible for the differences in color perception.
The results cannot be explained by differences in participants' level of effort, attention, or engagement with the task, as color perception was only impaired on the blue-yellow axis.
"We were surprised by how specific the effect was, that color was only impaired along the blue-yellow axis," says Thorstenson. "We did not predict this specific finding, although it might give us a clue to the reason for the effect in neurotransmitter functioning."
The researchers note that previous work has specifically linked color perception on the blue-yellow axis with the neurotransmitter dopamine.
Thorstenson points out that this research charts new territory, and that follow-up studies are essential to fully understanding the relationship between emotion and color perception:
"This is new work and we need to take time to determine the robustness and generalizability of this phenomenon before making links to application," he concludes.
http://www.sciencedaily.com/releases/2015/09/150902112006.htm
Link between insomnia, control of emotion
September 8, 2015
Science Daily/British Psychological Society (BPS)
People who are losing the ability to regulate their emotions may be more likely to suffer from insomnia. And if they do, that insomnia is more likely to become persistent, research suggests. Researchers surveyed 2333 adult members of the general public in Sweden. They were asked to complete a series of questionnaires on emotional regulation and a series on insomnia. The researchers found that a reduced ability to regulate emotions was associated with an 11 per cent increased risk of developing a new bout of insomnia or reporting persistent insomnia.
Those are the conclusions of research published in a British Psychological Society journal by a team led by Markus Jansson-Fröjmark from Örebro University, Sweden.
Markus Jansson-Fröjmark said: "These findings are important because, though the effect size is small, they suggest that teaching people strategies for regulating their emotions might help prevent new cases of insomnia to occur and decrease the risk of persistent insomnia."
The researchers, whose work is published in the British Journal of Health Psychology, surveyed 2333 adult members of the general public in Sweden. They were asked to complete a series of questionnaires on emotional regulation and a series on insomnia.
The questionnaires on emotional regulation asked about problems like difficulties with impulse control and lack of emotional awareness. Those on sleep problems asked about problems with falling asleep and with waking too early, and also about any difficulties these problems caused during the day.
When the results were analysed the researchers found there was no link between people's ability to regulate their emotions and their experience of insomnia.
But a different picture emerged when follow-up questionnaires were returned six months later by 1887 of the original participants and 18 months later by 1795 of them.
These results showed that participants whose ability to regulate their emotions had diminished since the original survey were more likely to have developed insomnia and that it was more likely to be persistent.
The researchers found that a reduced ability to regulate emotions was associated with an 11 per cent increased risk of developing a new bout of insomnia or reporting persistent insomnia.
http://www.sciencedaily.com/releases/2015/09/150908093953.htm
New technologies can help short circuit chronic pain
September 10, 2015
Science Daily/American Society of Anesthesiologists (ASA)
More than 100 million people in this country have pain that won't go away. Many of these chronic pain sufferers fail to get relief from pills, shots and even surgery, while others temporarily trade the pain for side effects such as drowsiness or digestive problems. Unfortunately, too many become addicted to medications while trying to relieve their pain.
As part of a comprehensive treatment plan, a variety of technologies offer new hope to people living with chronic pain.
Used by physician anesthesiologists who specialize in pain management, these techniques ease pain in various ways -- using radio waves, electrical pulses, image-guided injections and special pumps to deliver pain medication. Pain medicine specialists have extensive training and expertise in finding the cause of pain and working in partnership with patients to create a plan for managing pain and improving function.
"Pain is one of the most challenging things to treat because its source can be elusive," said Richard Rosenquist, M.D., chair of the American Society of Anesthesiologists® (ASA®) Committee on Pain Medicine and chairman of the department of pain management at the Anesthesiology Institute at the Cleveland Clinic. "That's why it's vital to see a physician specializing in pain medicine who can help identify the source of the pain and suggest which pain method might work best, including the more recent technical advances."
Pain Relief Techniques
Here are some of the latest high-tech methods for relieving chronic pain:
Radio Waves - Radiofrequency (RF) ablation involves heating a tiny area of nerve tissue, which short circuits pain signals. Using CT imaging as a guide, the pain medicine specialist inserts a needle into the nerve responsible for the pain and zaps it using an electric current created by radio waves. The relief can last for up to a year.
Blocking the Pain - Under X-ray guidance, pain medicine physicians can inject numbing medication that blocks or dampens pain, and might even stop chronic pain from developing. The location of the injection depends on the source and type of pain. For example, pain in the arm or face can be relieved by blocking nerves in the neck. Chronic abdominal pain or pain from cancers such as pancreatic cancer can be relieved by an injection into nerves supplying the abdomen. Relief may require a series of injections and may need to be repeated.
Electric Signals -- Transcutaneous electrical nerve stimulation (TENS) can provide short-term pain relief, especially for various types of muscle pain, by sending low voltage electric signals from a small device to the painful area through pads attached to the skin. The patient will feel little pulses when it's on. While researchers aren't sure why it works, they think it may either interrupt the nerve signals to the brain, or stimulate the production of "feel good" endorphins, the body's natural painkillers.
Spinal Cord Stimulation -- When other methods fail, a pain medicine specialist might recommend spinal cord stimulation (SCS), which uses a pacemaker-like device that replaces the pain with a more tolerable sensation, typically tingling or a massage-like feeling. The physician implants the device in the lower back, attaching it to tiny wires that are located in the spinal canal. When the patient feels pain, he or she can use a remote control device to send signals to the painful area. This technique can help with back pain as well as neuropathy -- nerve damage in the legs that causes numbness and pain. Neuropathy is common in people with diabetes.
High Frequency Spinal Cord Stimulation -- A recent study published in Anesthesiology, the medical journal of the ASA, showed that a special high frequency form of SCS provided significantly greater long-term relief for both chronic back and leg pain, compared to traditional low frequency SCS. The high frequency SCS also relieved pain without introducing the tingling or other stimulation-induced sensation that some patients find distracting.
Pumping the Pain Away -- Special pumps can be implanted that allow the patient to push a button and deliver local anesthetics, narcotics and other pain medications to the spinal cord. This can bring relief while avoiding the side effects that often come with taking these drugs by mouth. Patients also get a psychological boost by having direct control over their pain. These spinal drug pumps are most often used by people with cancer pain, but also by patients with other types of pain who had side effects when taking medication.
On the Horizon: Using Our Cells to Fight Pain -- One of the most promising research areas involves harvesting stem cells from a patient's bone marrow and injecting them into an area, such as the lower back, that has become painful because tissue has deteriorated. The hope is that the stem cells will build new, healthy tissue and relieve pain for good.
http://www.sciencedaily.com/releases/2015/09/150910141331.htm
Struggles with sleep may affect heart disease risk
September 10, 2015
Science Daily/American Heart Association
Young and middle-aged adults who get too much or too little sleep or have poor quality sleep are at higher risk for the early signs of heart disease than those who get adequate, good quality sleep, research shows.
Are you getting enough quality sleep? Are you sleeping longer than you should? Poor sleep habits may put you at higher risk for early signs of heart disease when compared to those who get adequate, good quality sleep, according to a study published in the American Heart Association journal Arteriosclerosis, Thrombosis and Vascular Biology.
"Inadequate sleep is a common problem and a likely source of poor health, including visible signs of disease, such as heart attack," said Chan-Won Kim, M.D., study co-lead author and clinical associate professor in the Center for Cohort Studies at Kangbuk Samsun Hospital, Sungkyunkwan University School of Medicine in Seoul, South Korea.
Researchers studied more than 47,000 young and middle-aged adults who completed a sleep questionnaire and had advanced tests to detect early coronary artery lesions and measure arterial stiffness. Early coronary lesions were detected as the presence of calcium in the coronary arteries and arterial stiffness was assessed by measuring the velocity, or speed, of the pulse wave between the arteries in the upper arm and ankle.
After measuring coronary calcium, researchers found:
• Adults who sleep five or fewer hours a day have 50 percent more calcium in their coronary arteries than those who sleep seven hours a day.
• Those who sleep nine or more hours a day have more than 70 percent more coronary calcium compared to those who sleep seven hours.
• Adults who reported poor sleep quality had more than 20 percent more coronary calcium than those who reported good sleep quality.
• "We also observed a similar pattern when we measured arterial stiffness," said Yoosoo Chang, M.D., Ph.D., study co-lead author and associate professor in the Center for Cohort Studies at Kangbuk Samsun Hospital. "Adults with poor sleep quality have stiffer arteries than those who sleep seven hours a day or had good sleep quality. Overall, we saw the lowest levels of vascular disease in adults sleeping seven hours a day and reporting good sleep quality."
The study's findings highlight the importance of adequate sleep quantity and quality to maintain cardiovascular health.
"For doctors, it might be necessary to assess patients' sleep quality when they evaluate the cardiovascular risk and the health status of men and women," Kim said.
The self-reported assessments of sleep duration and quality in the study may underestimate the cardiovascular risk, researchers said.
http://www.sciencedaily.com/releases/2015/09/150910164218.htm
Eating a lot of fish may help curb depression risk -- at least in Europe Association equally significant among men and women, pooled data analysis shows
September 10, 2015
Science Daily/BMJ
Eating a lot of fish may help curb the risk of depression -- at least in Europe -- suggests a pooled analysis of the available evidence. Depression affects an estimated 350 million people worldwide, and is projected to become the second leading cause of ill health by 2020.
The association between a fishy diet and mental health appears to be equally significant among men and women, the first analysis of its kind indicates.
Depression affects an estimated 350 million people worldwide, and is projected to become the second leading cause of ill health by 2020.
Several previous studies have looked at the possible role of dietary factors in modifying depression risk, but the findings have been inconsistent and inconclusive.
The researchers therefore pooled the data from relevant studies published between 2001 and 2014 to assess the strength of the evidence on the link between fish consumption and depression risk
After trawling research databases, they found 101 suitable articles, of which 16 were eligible for inclusion in the analysis. These 16 articles included 26 studies, involving 150, 278 participants.
Ten of the studies were cohort studies, which involve monitoring a group of people who don't have the condition in question for a period of time to see who develops it. The remainder were cross-sectional: these look at the association between a condition and other variables of interest in a defined population at a single point in time or over a brief period.
Ten of the studies involved participants from Europe; 7 those from North America; the rest involved participants in Asia, Oceania, and South America.
After pooling all the data together, a significant association emerged between those eating the most fish and a 17% reduction in depression risk compared with those eating the least. This was found in both cohort and cross-sectional studies, but only for the European studies.
When the researchers looked specifically at gender, they found a slightly stronger association between high fish consumption and lowered depression risk in men (20%). Among women, the associated reduction in risk was 16%.
This is an observational study so no definitive conclusions can be drawn about cause and effect, added to which fish consumption was measured using different dietary assessment methods across the various studies. But there may be a plausible biological explanation for the link, suggest the researchers.
For example, it has been suggested that the omega 3 fatty acids found in fish may alter the microstructure of brain membranes and modify the activity of the neurotransmitters, dopamine and serotonin, both of which are thought to be involved in depression.
Furthermore, the high quality protein, vitamins, and minerals found in fish may help stave off depression, while eating a lot of fish may be an indicator of a healthy and more nutritious diet, suggest the researchers.
"Higher fish consumption may be beneficial in the primary prevention of depression," they conclude, adding: "Future studies are needed to further investigate whether this association varies according to the type of fish."
http://www.sciencedaily.com/releases/2015/09/150910185034.htm
Long sleep and high blood copper levels go hand in hand
September 14, 2015
Science Daily/University of Eastern Finland
People who sleep fewer than 6 hours or more than 10 hours per night suffer from low-grade inflammation more often than people who sleep 7-8 hours per night. Earlier studies have found a relation between reduced sleep and low-grade inflammation, according to one of the study researchers. Furthermore, low-grade inflammation occurs in overweight, depression and diabetes. This new study is the first to analyze the association between sleep duration and serum micronutrient concentrations in a large sample, and it found a link between high serum copper concentration and long sleep duration.
"Earlier studies have found a relation between reduced sleep and low-grade inflammation," says Maria Luojus, MHSc, one of the study researchers.
Furthermore, low-grade inflammation occurs in overweight, depression and diabetes.
The study is the first to analyse the association between sleep duration and serum micronutrient concentrations in a large sample, and it found a link between high serum copper concentration and long sleep duration. Serum micronutrient concentrations are affected by many factors, including an individual's general health and diet.
"Based on this study, however, it is impossible to say whether sleeping long results in high serum copper concentrations or vice versa," Luojus says.
It has been suggested that high serum copper concentration associates with pro-oxidative stress.
"Pro-oxidative stress is found in many chronic diseases, such as coronary artery disease. Nevertheless, when the study participants' cardiovascular diseases were taken account for, our results remained unchanged. The association between serum copper concentration and sleep duration persisted independently of cardiovascular diseases," Luojus says.
In addition to, the study participants' age, cumulative smoking history, alcohol consumption, depressive symptoms, physical activity and metabolic syndrome were taken into account in the data analysis.
The study involved 2,682 men living in Eastern Finland, participating the Kuopio Ischemic Heart Disease Risk Factor (KIHD) study. The KIHD study has been ongoing at the University of Eastern Finland in the Institute of Public Health and Clinical Nutrition since 1984.
http://www.sciencedaily.com/releases/2015/09/150914093054.htm
Controlling brain cells with sound waves
September 15, 2015
Science Daily/Salk Institute
http://images.sciencedaily.com/2015/09/150915135412_1_540x360.jpg
For the first time, sound waves are used to control brain cells. Salk scientists developed the new technique, dubbed sonogenetics, to selectively and noninvasively turn on groups of neurons in worms that could be a boon to science and medicine. So far, sonogenetics has only been applied to C. elegans neurons but the method may also work in humans.
Credit: Salk Institute
Salk scientists have developed a new way to selectively activate brain, heart, muscle and other cells using ultrasonic waves. The new technique, dubbed sonogenetics, has some similarities to the burgeoning use of light to activate cells in order to better understand the brain.
This new method--which uses the same type of waves used in medical sonograms--may have advantages over the light-based approach--known as optogenetics--particularly when it comes to adapting the technology to human therapeutics. It was described September 15, 2015 in the journal Nature Communications.
"Light-based techniques are great for some uses and I think we're going to continue to see developments on that front," says Sreekanth Chalasani, an assistant professor in Salk's Molecular Neurobiology Laboratory and senior author of the study. "But this is a new, additional tool to manipulate neurons and other cells in the body."
In optogenetics, researchers add light-sensitive channel proteins to neurons they wish to study. By shining a focused laser on the cells, they can selectively open these channels, either activating or silencing the target neurons. But using an optogenetics approach on cells deep in the brain is difficult: typically, researchers have to perform surgery to implant a fiber optic cable that can reach the cells. Plus, light is scattered by the brain and by other tissues in the body.
Chalasani and his group decided to see if they could develop an approach that instead relied on ultrasound waves for the activation. "In contrast to light, low-frequency ultrasound can travel through the body without any scattering," he says. "This could be a big advantage when you want to stimulate a region deep in the brain without affecting other regions," adds Stuart Ibsen, a postdoctoral fellow in the Chalasani lab and first author of the new work.
Chalasani and his colleagues first showed that, in the nematode Caenorhabditis elegans, microbubbles of gas outside of the worm were necessary to amplify the low-intensity ultrasound waves. "The microbubbles grow and shrink in tune with the ultrasound pressure waves," Ibsen says. "These oscillations can then propagate noninvasively into the worm."
Next, they found a membrane ion channel, TRP-4, which can respond to these waves. When mechanical deformations from the ultrasound hitting gas bubbles propagate into the worm, they cause TRP-4 channels to open up and activate the cell. Armed with that knowledge, the team tried adding the TRP-4 channel to neurons that don't normally have it. With this approach, they successfully activated neurons that don't usually react to ultrasound.
So far, sonogenetics has only been applied to C. elegans neurons. But TRP-4 could be added to any calcium-sensitive cell type in any organism including humans, Chalasani says. Then, microbubbles could be injected into the bloodstream, and distributed throughout the body--an approach already used in some human imaging techniques. Ultrasound could then noninvasively reach any tissue of interest, including the brain, be amplified by the microbubbles, and activate the cells of interest through TRP-4. And many cells in the human body, he points out, can respond to the influxes of calcium caused by TRP-4.
"The real prize will be to see whether this could work in a mammalian brain," Chalasani says. His group has already begun testing the approach in mice. "When we make the leap into therapies for humans, I think we have a better shot with noninvasive sonogenetics approaches than with optogenetics."
Both optogenetics and sonogenetics approaches, he adds, hold promise in basic research by letting scientists study the effect of cell activation. And they also may be useful in therapeutics through the activation of cells affected by disease. However, for either technique to be used in humans, researchers first need to develop safe ways to deliver the light or ultrasound-sensitive channels to target cells.
http://www.sciencedaily.com/releases/2015/09/150915135412.htm
Fruit and vegetables aren't only good for a healthy body; they protect your mind too
September 16, 2015
Science Daily/BioMed Central
Eating a Mediterranean diet or other healthy dietary pattern, comprising of fruit, vegetables, legumes, and nuts and low in processed meats, is associated with preventing the onset of depression, according to research. A large study of 15,093 people suggests depression could be linked with nutrient deficits.
http://images.sciencedaily.com/2015/09/150916215535_1_540x360.jpg
A healthy diet heavy in vegetables, fruits and nuts is associated with preventing the onset of depression.
Credit: © vpardi / Fotolia
Following extensive research into diet and its effect on our physical health, researchers are now exploring the link between nutrition and mental health. This is the first time that several healthy dietary patterns and their association with the risk of depression have been analyzed together.
The researchers compared three diets; the Mediterranean diet, the Pro-vegetarian Dietary Pattern and Alternative Healthy Eating Index-2010. Participants used a scoring system to measure their adherence to the selected diet, i.e. the higher the dietary score indicated that the participant was eating a healthier diet.
Food items such as meat and sweets (sources of animal fats: saturated and trans fatty acids) were negatively scored, while nuts, fruits and vegetables (sources of omega-3 fatty acids, vitamins and minerals respectively) were positively scored.
Lead researcher, Almudena Sanchez-Villegas, University of Las Palmas de Gran Canaria, says "We wanted to understand what role nutrition plays in mental health, as we believe certain dietary patterns could protect our minds. These diets are all associated with physical health benefits and now we find that they could have a positive effect on our mental health."
"The protective role is ascribed to their nutritional properties, where nuts, legumes, fruits and vegetables (sources of omega-3 fatty acids, vitamins and minerals) could reduce the risk of depression."
The study included 15,093 participants free of depression at the beginning of the study. They are former students of the University of Navarra, Spain, registered professionals from some Spanish provinces and other university graduates. All are part of the SUN (Seguimiento Universidad de Navarra) Project, a cohort study started on 21st December 1999. The cohort has been used to identify dietary and lifestyle determinants of various conditions, including diabetes, obesity and depression.
Questionnaires to assess dietary intake were completed at the start of the project and again after 10 years. A total of 1,550 participants reported a clinical diagnosis of depression or had used antidepressant drugs after a median follow-up of 8.5 years.
The Alternative Healthy Eating Index-2010 was associated with the greatest reduction of risk of depression but most of the effect could be explained by its similarity with the Mediterranean Diet. Thus, common nutrients and food items such as omega-3 fatty acids, vegetables, fruits, legumes, nuts and moderate alcohol intake present in both patterns (Alternative Healthy Eating Index-2010 and Mediterranean diet) could be responsible for the observed reduced risk in depression associated with a good adherence to the Alternative Healthy Eating Index-2010.
Almudena Sanchez-Villegas says, "A threshold effect may exist. The noticeable difference occurs when participants start to follow a healthier diet. Even a moderate adherence to these healthy dietary patterns was associated with an important reduction in the risk of developing depression. However, we saw no extra benefit when participants showed high or very high adherence to the diets.
So, once the threshold is achieved, the reduced risk plateaus even if participants were stricter with their diets and eating more healthily. This dose-response pattern is compatible with the hypothesis that suboptimal intake of some nutrients (mainly located in low adherence levels) may represent a risk factor for future depression."
A limitation of this study was that the results are based on self-reported dietary intake and a self-reported clinical diagnosis of depression. More research is needed to predict the role of nutrient intake for neurophysiological requirements and identify whether it is minerals and vitamins or proteins and carbohydrates that cause depression.
http://www.sciencedaily.com/releases/2015/09/150916215535.htm
Caffeine at night delays human circadian clock Double espresso before bedtime induces 40-minute time delay in internal clock
September 16, 2015
Science Daily/University of Colorado at Boulder
For the first time, research shows that evening caffeine delays the internal circadian clock that tells us when to get ready for sleep and when to prepare to wake up.
http://images.sciencedaily.com/2015/09/150916161833_1_540x360.jpg
The results of this study may help to explain why caffeine-drinking "night owls" go to bed later and wake up later and may have implications for the treatment of some circadian sleep-wake disorders.
Credit: © patcharaporn1984 / Fotolia
It's no secret that slugging down caffeinated drinks in the evening can disrupt sleep.
But a new study led by the University of Colorado Boulder and the Medical Research Council's Laboratory of Molecular Biology in Cambridge, England shows for the first time that evening caffeine delays the internal circadian clock that tells us when to get ready for sleep and when to prepare to wake up. The research team showed the amount of caffeine in a double espresso or its equivalent three hours before bedtime induced a 40-minute phase delay in the roughly 24-hour human biological clock.
The study also showed for the first time how caffeine affects "cellular timekeeping" in the human body, said CU-Boulder Professor Kenneth Wright, who co-led the study with John O'Neill of the Medical Research Council's Laboratory of Molecular Biology (LMB) in Cambridge. While it has been known that caffeine influences circadian clocks of even primitive creatures like algae and fruit flies, the new study shows that the internal clocks in human cells can be impacted by caffeine intake.
"This is the first study to show that caffeine, the mostly widely used psychoactive drug in the world, has an influence on the human circadian clock," said Wright, a professor in CU-Boulder's Department of Integrative Physiology. "It also provides new and exciting insights into the effects of caffeine on human physiology."
A paper on the subject led by Wright and O'Neill is being published online in the Sept 16 issue of Science Translational Medicine.
For the study the team recruited five human subjects, three females and two males, who went though a double-blind, placebo-controlled 49-day protocol through CU-Boulder's Sleep and Chronobiology Laboratory, which is directed by Wright. The subjects were tested under four conditions: low light and a placebo pill; low light and the equivalent of a 200-milligram caffeine pill dependent on the subject's weight; bright light and a placebo pill; and bright light and the caffeine pill.
Saliva samples of each participant were tested periodically during the study for levels of the hormone melatonin, which is produced naturally by the pineal gland when directed to do so by the brain's "master clock." The master clock is re-set by exposure to light and coordinates cellular clocks throughout the human body. Melatonin levels in the blood increase to signal the onset of biological nighttime during each 24-hour period and decrease at the start of biological daytime, said Wright.
Those who took the caffeine pill under low-light conditions were found to have a roughly 40-minute delay in their nightly circadian rhythm compared to those who took the placebo pill under low light conditions, said Wright. The magnitude of delay from the caffeine dose was about half that of the delay induced in test subjects by a three-hour exposure to bright, overhead light that began at each person's normal bedtime.
The study also showed that bright light alone and bright light combined with caffeine induced circadian phase delays in the test subjects of about 85 minutes and 105 minutes respectively. There were no significant differences between the dim light/caffeine combination and the bright light/placebo combination. Nor were there significant differences between the bright light/placebo and bright light/caffeine combinations. The results may indicate a "ceiling" was reached in the phase delay of the human circadian clock due to the external factors, Wright said.
In addition, researchers at O'Neill's lab at the LMB in Cambridge used "reporter" genes that made cells glow when the clock genes were expressed to measure changes caused by caffeine. O'Neill's group showed that caffeine can block cell receptors of the neurotransmitter adenosine, which normally promotes sleep and suppresses arousal.
The results may help to explain why caffeine-drinking "night owls" go to bed later and wake up later and may have implications for the treatment of some circadian sleep-wake disorders, said Wright.
The new results could benefit travelers. Properly timed caffeine use could help shift the circadian clocks of those flying west over multiple time zones, said Wright.
In a 2013 study, Wright and his research team showed one week of camping in the Rocky Mountains with no artificial light, not even flashlights, synchronized the circadian clocks of the eight study subjects with the timing of sunrise and sunset.
http://www.sciencedaily.com/releases/2015/09/150916161833.htm
Negative spiritual beliefs associated with more pain and worse physical, mental health
September 23, 2015
Science Daily/University of Missouri Health
Individuals who blame karma for their poor health have more pain and worse physical and mental health, according to a new study. Targeted interventions to counteract negative spiritual beliefs could help some individuals decrease pain and improve their overall health, the researchers said.
"In general, the more religious or spiritual you are, the healthier you are, which makes sense," said Brick Johnstone, a neuropsychologist and professor of health psychology in the MU School of Health Professions. "But for some individuals, even if they have even the smallest degree of negative spirituality -- basically, when individuals believe they're ill because they've done something wrong and God is punishing them -- their health is worse."
Johnstone and his colleagues studied nearly 200 individuals to find out how their spiritual beliefs affected their health outcomes. Individuals in the study had a range of health conditions, such as cancer, traumatic brain injury or chronic pain, and others were healthy. The researchers divided the individuals into two groups: a negative spirituality group that consisted of those who reported feeling abandoned or punished by a higher power, and a no negative spirituality group that consisted of people who didn't feel abandoned or punished by a higher power. Participants answered questions about their emotional and physical health, including physical pain.
Those in the negative spirituality group reported significantly worse pain as well as worse physical and mental health while those with positive spirituality reported better mental health. However, even if individuals reported positive spiritual beliefs, having any degree of negative spiritual belief contributed to poorer health outcomes, the researchers found.
"Previous research has shown that about 10 percent of people have negative spiritual beliefs; for example, believing that if they don't do something right, God won't love them," Johnstone said. "That's a negative aspect of religion when people believe, 'God is not supportive of me. What kind of hope do I have?' However, when people firmly believe God loves and forgives them despite their shortcomings, they had significantly better mental health."
Individuals with negative spiritual beliefs also reported participating in religious practices less frequently and having lower levels of positive spirituality and forgiveness. Interventions that help combat negative spiritual beliefs and promote positive spiritual beliefs could help some individuals improve their pain and their mental health, Johnstone said.
http://www.sciencedaily.com/releases/2015/09/150923125336.htm
Sleep may strengthen long-term memories in the immune system
September 29, 2015
Science Daily/Cell Press
More than a century ago, scientists demonstrated that sleep supports the retention of memories of facts and events. Later studies have shown that slow-wave sleep, often referred to as deep sleep, is important for transforming fragile, recently formed memories into stable, long-term memories. Now, in a new article, researchers propose that deep sleep may also strengthen immunological memories of previously encountered pathogens.
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The immune system "remembers" an encounter with a bacteria or virus by collecting fragments from the bug to create memory T cells, which last for months or years and help the body recognize a previous infection and quickly respond.
Credit: © Sabphoto / Fotolia
"While it has been known for a long time that sleep supports long-term memory formation in the psychological domain, the idea that long-term memory formation is a function of sleep effective in all organismic systems is in our view entirely new," says senior author Jan Born of the University of Tuebingen. "We consider our approach toward a unifying concept of biological long-term memory formation, in which sleep plays a critical role, a new development in sleep research and memory research."
The immune system "remembers" an encounter with a bacteria or virus by collecting fragments from the bug to create memory T cells, which last for months or years and help the body recognize a previous infection and quickly respond. These memory T cells appear to abstract "gist information" about the pathogens, as only T cells that store information about the tiniest fragments ever elicit a response. The selection of gist information allows memory T cells to detect new pathogens that are similar, but not identical, to previously encountered bacteria or viruses.
Studies in humans have shown that long-term increases in memory T cells are associated with deep slow-wave sleep on the nights after vaccination. Taken together, the findings support the view that slow-wave sleep contributes to the formation of long-term memories of abstract, generalized information, which leads to adaptive behavioral and immunological responses. The obvious implication is that sleep deprivation could put your body at risk.
"If we didn't sleep, then the immune system might focus on the wrong parts of the pathogen," Born says. "For example, many viruses can easily mutate some parts of their proteins to escape from immune responses. If too few antigen-recognizing cells [the cells that present the fragments to T cells] are available, then they might all be needed to fight off the pathogen. In addition to this, there is evidence that the hormones released during sleep benefit the crosstalk between antigen-presenting and antigen-recognizing cells, and some of these important hormones could be lacking without sleep."
Born says that future research should examine what information is selected during sleep for storage in long-term memory, and how this selection is achieved. In the end, this research could have important clinical implications.
"In order to design effective vaccines against HIV, malaria, and tuberculosis, which are based on immunological memory, the correct memory model must be available," Born says. "It is our hope that by comparing the concepts of neuronal and immunological memory, a model of immunological memory can be developed which integrates the available experimental data and serves as a helpful basis for vaccine development."
http://www.sciencedaily.com/releases/2015/09/150929142022.htm
Happy head, happy heart: Positive emotions may promote heart-healthy behaviors
October 5, 2015
Science Daily/Penn State
People with heart disease may benefit from maintaining positive emotions, according to health researchers. The researchers assessed psychological well-being of participants at baseline and again at a five-year follow-up by asking the participants to rate the extent that they had felt 10 specified positive emotions, including "interested," "proud," "enthusiastic" and "inspired." Physical activity, sleep quality, medication adherence and alcohol and cigarette use were also measured at baseline and again five years later.
Over the course of five years the researchers tracked more than 1,000 patients with coronary heart disease. Patients who reported higher positive psychological states were more likely to be physically active, sleep better and take their heart medications and were also less likely to smoke, compared to patients with lower levels of positive states.
"Negative emotions and depression are known to have harmful effects on health, but it is less clear how positive emotions might be health-protective," said Nancy L. Sin, postdoctoral fellow in the Center for Healthy Aging and in the department of biobehavioral health at Penn State. "We found that positive emotions are associated with a range of long-term health habits, which are important for reducing the risk of future heart problems and death."
The researchers assessed psychological well-being of participants at baseline and again at a five-year follow-up by asking the participants to rate the extent that they had felt 10 specified positive emotions, including "interested," "proud," "enthusiastic" and "inspired." Physical activity, sleep quality, medication adherence and alcohol and cigarette use were also measured at baseline and again five years later. The researchers report their findings in the journal Psychosomatic Medicine.
"Higher levels of positive emotions were associated with less smoking, greater physical activity, better sleep quality and more adherence to medications" at baseline, said the researchers. They found no correlation between positive emotions and alcohol use. The results took into account patients' demographic factors, depressive symptoms and the severity of their heart conditions.
Though positive emotions at baseline did not predict changes in health behaviors five years later, increases in positive emotions across the five-year period were associated with improvements in physical activity, sleep quality and medication adherence.
There are a number of reasons why positive emotions are linked to optimal health habits, the researchers suggest. People with greater positive well-being may be more motivated and persistent in engaging in healthy behaviors. They might have more confidence in their abilities to maintain routines such as physical activity and sleep hygiene. Positive emotions may also enable people to better adjust their health goals and to proactively cope with stress and setbacks.
"Efforts to sustain or enhance positive emotions may be promising for promoting better health behaviors," said the researchers.
This research sets the stage for future work on interventions to improve health habits, Sin noted. Further research with other chronic disease populations and with electronic tracking of health behaviors should be conducted, she said.
http://www.sciencedaily.com/releases/2015/10/151005132621.htm
Exercise and stop smoking to improve depression after heart attack
October 10, 2015
Science Daily/European Society of Cardiology
Exercise and stop smoking to improve depression after a heart attack, experts urge.
"Depression is almost three times more common in people who have had a heart attack than in those who haven't," said Dr Manuela Abreu, a psychiatrist at the University of Lisbon, Portugal. "Cardiac rehabilitation with aerobic exercise can reduce depressive symptoms and improve cardiovascular fitness."
"Patients who are depressed after a heart attack have a two-fold risk of having another heart attack or dying compared to those who are not depressed," added Dr David Nanchen, head of the Prevention Centre, Department of Ambulatory Care and Community Medicine, University of Lausanne, Switzerland.
Dr Nanchen's research shows that exercise and stopping smoking may improve depression after heart attack. He studied 1,164 patients who were part of the Swiss Acute Coronary Syndromes (ACS) cohort, a large prospective multicentre study of patients with ACS in Switzerland. Patients were enrolled between 2009 and 2013 and followed up for one year. Depression was assessed at enrolment and at one year.
The researchers investigated the impact of a number of factors on improvement of depression after heart attack. These included blood cholesterol management, blood pressure control, smoking cessation for smokers, reduction of alcohol for those consuming more than 14 drinks per week, intensification of physical activity, and guideline recommended medications.
The study found that at one year, 27% of heart attack patients had persistent or new depression and 11% had improved depression. Patients with depression were less frequently married, had more diabetes, and were more frequently smokers than those without depression.
At one year, smoking cessation had the strongest association with improvement of depression with a 2.3 greater chance of improving depression in quitters compared to those who continued smoking. Depressed patients who had higher physical activity at the beginning of the study were also more prone to improve their depression.
"Heart attack patients who smoke and are depressed are much more likely to improve their depression if they kick the habit," said Dr Nanchen. "While our observational study was unable to find an impact of exercise after heart attack on depressive symptoms, we did show that patients who were already physically active were more able to improve their depression. We believe that the benefits of exercise after heart attack would be shown in a randomised trial, but such a study is difficult to perform for ethical reasons."
"More than one-quarter of patients in our study reported symptoms of depression after their heart attack, which shows this is a big issue," said Dr Nanchen. "Some had chronic depression which started before their heart attack while others became depressed as an acute reaction to the hospitalisation and the event."
Depressive symptoms in cardiac patients often differ from those of psychiatric patients. "Frequently they don't say they feel sad or hopeless but instead complain of insomnia, fatigue or body pain," said Dr Abreu. "The different clinical presentation contributes to the underdiagnosis of depression in cardiac patients."
She added: "Depression after a heart attack can lead to poor adherence to treatment, skipping medical appointments, smoking, sedentary lifestyle, unhealthy diet, social isolation, and poor self esteem."
The behavioural changes associated with depression may be partly responsible for the worse outcomes in heart attack patients who are depressed. Biological mechanisms, including changes to the autonomic nervous system and inflammatory factors, and decreased heart rate variability, may also play a role.
Dr Nanchen advised heart attack patients to discuss smoking cessation with their doctor and to be physically active. "You should do moderate to vigorous aerobic exercise for 30 minutes at least three times a week to be within recommended levels. Make sure you are working hard enough to break out in a sweat," he said. "This level of physical activity is good for your mental and physical health."
http://www.sciencedaily.com/releases/2015/10/151010225215.htm
How the brain controls sleep
Brain structure generates pockets of sleep within the brain
October 13, 2015
Science Daily/Massachusetts Institute of Technology
Neuroscientists have discovered a brain circuit that can trigger small regions of the brain to fall asleep or become less alert, while the rest of the brain remains awake. The researchers believe this may help the brain consolidate new memories by coordinating slow waves between different parts of the brain, allowing them to share information more easily.
http://images.sciencedaily.com/2015/10/151013182735_1_540x360.jpg
MIT neuroscientists have discovered a brain circuit that can trigger small regions of the brain to fall asleep or become less alert, while the rest of the brain remains awake.
Credit: Illustration by Jose-Luis Olivares/MIT
Sleep is usually considered an all-or-nothing state: The brain is either entirely awake or entirely asleep. However, MIT neuroscientists have discovered a brain circuit that can trigger small regions of the brain to fall asleep or become less alert, while the rest of the brain remains awake.
This circuit originates in a brain structure known as the thalamic reticular nucleus (TRN), which relays signals to the thalamus and then the brain's cortex, inducing pockets of the slow, oscillating brain waves characteristic of deep sleep. Slow oscillations also occur during coma and general anesthesia, and are associated with decreased arousal. With enough TRN activity, these waves can take over the entire brain.
The researchers believe the TRN may help the brain consolidate new memories by coordinating slow waves between different parts of the brain, allowing them to share information more easily.
"During sleep, maybe specific brain regions have slow waves at the same time because they need to exchange information with each other, whereas other ones don't," says Laura Lewis, a research affiliate in MIT's Department of Brain and Cognitive Sciences and one of the lead authors of the new study, which appears in the journal eLife.
The TRN may also be responsible for what happens in the brain when sleep-deprived people experience brief sensations of "zoning out" while struggling to stay awake, the researchers say.
The paper's other first author is Jakob Voigts, an MIT graduate student in brain and cognitive sciences. Senior authors are Emery Brown, the Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience at MIT and an anesthesiologist at Massachusetts General Hospital, and Michael Halassa, an assistant professor at New York University. Other authors are MIT research affiliate Francisco Flores and Matthew Wilson, the Sherman Fairchild Professor in Neurobiology and a member of MIT's Picower Institute for Learning and Memory.
Local control
Until now, most sleep research has focused on global control of sleep, which occurs when the entire brain is awash in slow waves -- oscillations of brain activity created when sets of neurons are silenced for brief periods.
However, recent studies have shown that sleep-deprived animals can exhibit slow waves in parts of their brain while they are still awake, suggesting that the brain can also control alertness at a local level.
The MIT team began its investigation of local control of alertness or drowsiness with the TRN because its physical location makes it perfectly positioned to play a role in sleep, Lewis says. The TRN surrounds the thalamus like a shell and can act as a gatekeeper for sensory information entering the thalamus, which then sends information to the cortex for further processing.
Using optogenetics, a technique that allows scientists to stimulate or silence neurons with light, the researchers found that if they weakly stimulated the TRN in awake mice, slow waves appeared in a small part of the cortex. With more stimulation, the entire cortex showed slow waves.
"We also found that when you induce these slow waves across the cortex, animals start to behaviorally act like they're drowsy. They'll stop moving around, their muscle tone will go down," Lewis says.
The researchers believe the TRN fine-tunes the brain's control over local brain regions, enhancing or reducing slow waves in certain regions so those areas can communicate with each other, or inducing some areas to become less alert when the brain is very drowsy. This may explain what happens in humans when they are sleep-deprived and momentarily zone out without really falling asleep.
"I'm inclined to think that happens because the brain begins to transition into sleep, and some local brain regions become drowsy even if you force yourself to stay awake," Lewis says.
Natural sleep and general anesthesia
Understanding how the brain controls arousal could help researchers design new sleep and anesthetic drugs that create a state more similar to natural sleep. Stimulating the TRN can induce deep, non-REM-like sleep states, and previous research by Brown and colleagues uncovered a circuit that turns on REM sleep.
Brown adds, "The TRN is rich in synapses -- connections in the brain -- that release the inhibitory neurotransmitter GABA. Therefore, the TRN is almost certainly a site of action of many anesthetic drugs, given that a large classes of them act at these synapses and produce slow waves as one of their characteristic features."
Previous work by Lewis and colleagues has shown that unlike the slow waves of sleep, the slow waves under general anesthesia are not coordinated, suggesting a mechanism for why these drugs impair information exchange in the brain and produce unconsciousness.
http://www.sciencedaily.com/releases/2015/10/151013182735.htm
'Paleo' sleep? Sorry, pre-modern people don't get more Zzzzs than we do
October 15, 2015
Science Daily/Cell Press
http://images.sciencedaily.com/2015/10/151015131832_1_540x360.jpg
This photo shows two San people in Tsumkwe, Namibia, taken at the start of the study.
Credit: Josh Davimes
It's tempting to believe that people these days aren't getting enough sleep, living as we do in our well-lit houses with TVs blaring, cell phones buzzing, and a well-used coffee maker in every kitchen. But new evidence reported in the Cell Press journal Current Biology on October 15 shows that three ancient groups of hunter-gatherers--living in different parts of the world without any of those trappings of modern life--don't get any more sleep than we do.
Those traditional people sleep a little under 6.5 hours a night on average. They don't take regular naps. They don't go to sleep at dark, either. In other words, their sleep habits don't look so different from ours, although they usually do wake up before the sun rises.
"The short sleep in these populations challenges the belief that sleep has been greatly reduced in the 'modern world,'" says Jerome Siegel of the University of California, Los Angeles. "This has important implications for the idea that we need to take sleeping pills because sleep has been reduced from its 'natural level' by the widespread use of electricity, TV, the Internet, and so on."
To get a handle on how people slept before the modern era, Siegel and his colleagues looked to three traditional human hunter-gatherer societies: the Hadza of Tanzania, the San of Namibia, and the Tsimane of Bolivia. The researchers recorded the sleeping habits of 94 individuals around the clock to collect data representing 1,165 days in all.
What they found was a surprising similarity across those three groups. "Despite varying genetics, histories, and environments, we find that all three groups show a similar sleep organization, suggesting that they express core human sleep patterns, probably characteristic of pre-modern-era Homo sapiens," Siegel says.
Group sleep time averaged between 5.7 and 7.1 hours, with between 6.9 and 8.5 hours between the beginning and end of the sleep period. Those amounts are at the low end of durations reported in "industrial societies."
Hunter-gatherers sleep an hour more in the winter than they do in the summer. Although they lack electric lights, none of the groups went to sleep with the sun. On average, they stayed up a little over three hours after the sun went down and woke up before sunrise.
It appears that their sleep time may have more to do with temperature than with light. Those ancient groups all went to sleep as the temperature fell and slept through the coldest part of the night.
There is one important way in which hunter-gatherers aren't like us: very few of them suffer from chronic insomnia--a common complaint in the US. That raises an interesting possibility, the researchers say.
"Mimicking aspects of the natural environment experienced by these groups might be effective in treating certain modern sleep disorders, particularly insomnia, a disorder affecting more than 20 percent of the US population," Siegel says.
The authors were supported by the National Institutes of Health, the National Institute on Aging, the National Research Foundation of South Africa, and the National Science Foundation.
http://www.sciencedaily.com/releases/2015/10/151015131832.htm