Tag: sleep

Categories : Cardiovascular DiseaseTags :

Sleep Now Part of American Heart Association’s Cardiovascular Health Score

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Sleep duration is now considered an essential component for ideal heart and brain health. Life’s Essential 8™ cardiovascular health score replaces Life’s Simple 7™, according to a new American Heart Association advisory published in Circulation.

Other updates to the measures of optimal cardiovascular health, now for anyone ages 2 and older, include a new guide to assess diet; accounting for exposure to second-hand smoke and vaping; using non-HDL cholesterol instead of total cholesterol to measure blood lipids; and expanding the blood sugar measure to include haemoglobin A1c to assess Type 2 diabetes risk.

“The new metric of sleep duration reflects the latest research findings: sleep impacts overall health, and people who have healthier sleep patterns manage health factors such as weight, blood pressure or risk for Type 2 diabetes more effectively,” said American Heart Association President Professor Donald M. Lloyd-Jones, MD, who led the advisory writing group. “In addition, advances in ways to measure sleep, such as with wearable devices, now offer people the ability to reliably and routinely monitor their sleep habits at home.”

The Association first defined the seven metrics for cardiovascular health in 2010 to identify the specific health behaviours and health factors that drive optimal heart and brain health.

After 12 years and more than 2400 scientific papers on the topic, new discoveries in heart and brain health and in the ways to measure cardiovascular health provided an opportunity to revisit each health component in more detail. Four of the original metrics have been redefined for consistency with newer clinical guidelines or compatibility with new measurement tools. Also, the scoring system can now be applied to anyone ages 2 and older.

The Life’s Essential 8™ components of optimal cardiovascular health are divided into two major areas: health behaviours (diet, physical activity, nicotine exposure and sleep) and health factors (BMI, cholesterol levels, blood sugar and blood pressure). “The idea of optimal cardiovascular health is important because it gives people positive goals to work toward at any stage of life,” said Lloyd-Jones.

“Life’s Simple 7™ has served as a proven, powerful tool for understanding how to achieve healthy aging and ways to improve cardiovascular health while decreasing the risks of developing heart disease and stroke, as well as cancer, dementia and many other chronic diseases,” he said. “Given the evolving research, it was important to address some limitations to the original metrics, particularly in ways they’ve been applied to people from diverse racial and ethnic populations.”

Prof Lloyd-Jones explained that some of the previous metrics, such as diet, were not as sensitive to differences among people, or as responsive to changes over time within a single individual. “We felt it was the right time to conduct a comprehensive review of the latest research to refine the existing metrics and consider any new metrics that add value to assessing cardiovascular health for all people.”

Life’s Essential 8™ includes:

  1. Diet (updated):  A new guide to assess diet quality for adults and children at the individual level (for individual health care and dietary counselling) and at the population level (for research and public health purposes).
  2. Physical activity (no changes): The optimal level is 150 minutes of moderate physical activity or more per week or 75 minutes per week of vigorous-intensity physical activity for adults; 420 minutes or more per week for children ages 6 and older; and age-specific modifications for younger children.
  3. Nicotine exposure (updated): Use of inhaled nicotine-delivery systems, which includes e-cigarettes or vaping devices, is added since the previous metric only monitored traditional, combustible cigarettes. This reflects use by adults and youth and their implications on long-term health. Life’s Essential 8™ also includes second-hand smoke exposure for children and adults.
  4. Sleep duration (new): Sleep duration is associated with cardiovascular health. Measured by average hours of sleep per night, the ideal level is 7-9 hours daily for adults. Ideal daily sleep ranges for children are 10-16 hours per 24 hours for ages 5 and younger; 9-12 hours for ages 6-12 years; and 8-10 hours for ages 13-18 years.
  5. Body mass index (no changes): The writing group acknowledges that body mass index (BMI) is an imperfect metric, yet it is easily calculated and widely available; therefore, BMI continues as a reasonable gauge to assess weight categories that may lead to health problems. BMI of 18.5–24.9 is associated with the highest levels of cardiovascular health. The writing group notes that BMI ranges and the subsequent health risks associated with them may differ among people from diverse racial or ethnic backgrounds or ancestry. This aligns with the World Health Organization’s recommendations to adjust BMI ranges for people of Asian or Pacific Islander ancestry because recent evidence indicates their risk of conditions such as  CVD or Type 2 diabetes is higher at a lower BMI.
  6. Blood lipids (updated): The metric for blood lipids (cholesterol and triglycerides) is updated to use non-HDL cholesterol as the preferred number to monitor, rather than total cholesterol. Other forms of cholesterol, when high, are linked to CVD risk. This shift is made because non-HDL cholesterol can be measured without fasting beforehand (thereby increasing its availability at any time of day and implementation at more appointments) and reliably calculated among all people.
  7. Blood glucose (updated): This metric is expanded to include the option of haemoglobin A1c readings or blood glucose levels for people with or without Type 1 or Type 2 diabetes or prediabetes. Haemoglobin A1c can better reflect long-term glycaemic control.
  8. Blood pressure (no changes): Blood pressure criteria remain unchanged from the Association’s 2017 guidelines that established levels less than 120/80 mm Hg as optimal, and hypertension defined as 130-139 mm Hg systolic pressure (the top number in a reading) or 80-89 mm Hg diastolic pressure (bottom number).

Each component of Life’s Essential 8™, which is assessed by the My Life Check tool, has an updated scoring system ranging from 0 to 100 points. The overall cardiovascular health score from 0 to 100 points is the average of the scores for each of the 8 health measures. Overall scores below 50 indicate “poor” cardiovascular health, and 50-79 is considered “moderate” cardiovascular health. Scores of 80 and above indicate “high” cardiovascular health. The advisory recommends measuring cholesterol, blood sugar, blood pressure, height and weight at least every five years for the most complete and accurate Life’s Essential 8™ score.

The writing group also reviewed data about the impacts of stress, mental health and social determinants of health, such as access to health care, income or education level, and structural racism, which are critical to understanding the foundations of health, particularly among people from diverse racial and ethnic populations.

“We considered social determinants of health carefully in our update and determined more research is needed on these components to establish their measurement and inclusion in the future,” said Lloyd-Jones. “Nonetheless, social and structural determinants, as well as psychological health and well-being, are critical, foundational factors in an individual’s or a community’s opportunity to preserve and improve cardiovascular health. We must consider and address all of these issues for people to have the opportunity for a full, healthy life as measured by Life’s Essential 8™.”

Source: American Heart Association

Categories : HospitalsTags :

Physicians Prescribe Less Analgesic Medication during Nightshifts

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Physicians prescribe less analgesic medication during nightshifts than during the day, according to a new study published in PNAS.

In the first part of the study, 67 doctors were given empathy assessment tasks in the morning and asked to respond to simulated patient scenarios. These doctors were either at the end of a 26-hour shift or just beginning their workday. The study found that doctors who recently completed night shift showed less empathy for patient’s pain. For example, these physicians’ exhibited decreased emotional responses to pictures of people in pain and consistently scored their patients low on pain assessment charts.

In the second part of the study, the researchers looked at actual medical decisions made by emergency room doctors in the United States and Israel. Analysed 13 482 discharge letters for patients who came to the hospital in 2013–2020 with a chief complaint of pain, they found that physicians were 20–30% less likely to prescribe an analgesic during nightshifts (compared to daytime shifts) and in amounts less than generally recommended by the World Health Organization. “They’re tired and therefore they’re less empathic to patients’ pain. When we looked at ER doctors’ discharge papers, we found that they prescribed fewer painkillers,” explained Professor Shoham Choshen-Hillel from the Hebrew University of Jerusalem (HU)’s School of Business Administration and Federmann Center for the Study of Rationality, who led the study.

The bias persisted after adjusting for patients’ reported level of pain, patient and physician’s demographics, type of complaint, and emergency department characteristics. “Our takeaway is that nightshift work is an important and previously unrecognised source of bias in pain management, likely stemming from impaired perception of pain. The researchers explain that even medical experts, who strive to provide the best care for their patients, are susceptible to the effects of a nightshift,” noted co-lead author HU Psychology Department’s Dr Anat Perry.

Looking ahead, the researchers suggest implementing more structured pain management guidelines in hospitals. Another important implication relates to physician work structure, and the need to improve physicians’ working schedules. “Our findings may have implications for other workplaces that involve shiftwork and empathic decision-making, including crisis centres, first responders, and the military. In fact, these results should probably matter to all people who are sleep-deprived,” added co-lead author Dr Alex Gileles-Hillel from Hadassah Medical Center and HU.

Source: ScienceDaily

Categories : Cardiovascular DiseaseTags :

New Study Launched to Examine How Sleeps Aids Stroke Recovery

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Researchers at the University of East Anglia are launching a new study to investigate how sleep can aid in stroke recovery, by examining whether people’s sleep patterns influence recovery of neuromuscular function.

Lead researcher Prof Valerie Pomeroy, from UEA’s School of Health Sciences, said: “We want to better understand how the brain recovers after a stroke – so we will be investigating how stroke survivors regain movement, and how this is influenced by sleep and time.

“We hope to find out more about sleep patterns that are beneficial for movement recovery after stroke.”

The team are looking for people in the region who have had a stroke to take part in the study. Participants will undertake measures of daily activity, sleep and movement.

The project will involve measuring people’s movement using small sensors placed on the skin’s surface that record natural muscle activity whilst they carry out a daily task – picking up a telephone.

Participants will be asked to attend two visits at the university, during which participants will undertake the movement measures and complete questionnaires about how they sleep. 

In-between visits, participants will wear a motion watch on each wrist for seven days to measure their everyday activity at home.

Prof Valerie Pomeroy said: “There is strong evidence that physiotherapy improves the ability of people to move and be independent after a stroke.  But at six months after stroke many people remain unable to produce the movement needed for everyday activity such as answering a telephone. 

“We are undertaking this study to understand more about whether this situation could be improved by using interventions to change a patient’s sleep pattern and thus improve recovery of movement ability.”

Source: University of East Anglia

Categories : AgeingTags :

Seven Hours’ Sleep is Optimal in Middle Age and Older

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According to research published in Nature Aging, seven hours is the ideal amount of sleep for people in their middle age and upwards, with too little or too much little sleep associated with poorer cognitive performance and mental health.

Sleep plays an important role in enabling cognitive function and maintaining good psychological health, and also removes waste products from the brain. Alterations in sleep patterns appear during ageing, including difficulty falling asleep and staying asleep, and decreased quantity and quality of sleep. It is thought that these sleep disturbances may contribute to cognitive decline and psychiatric disorders in the ageing population.

Scientists from the UK and China examined data from nearly 500 000 adults aged 38–73 years from the UK Biobank. Participants were asked about their sleeping patterns, mental health and wellbeing, and took part in a series of cognitive tests. Brain imaging and genetic data were available for almost 40 000 of the study participants.

The researchers found in their analysis that both insufficient and excessive sleep duration were associated with impaired cognitive performance, such as processing speed, visual attention, memory and problem-solving skills. The optimal amount of sleep was found to be seven hours per night for cognitive performance and good mental health. More symptoms of anxiety and depression and worse overall wellbeing were associated with sleeping for longer or shorter durations.

The researchers say one possible reason for the association between insufficient sleep and cognitive decline may be due to the disruption of slow-wave — ‘deep’ — sleep. Disruption to this type of sleep has been shown to have a close link with memory consolidation as well as the build-up of amyloid — a key protein which, when it misfolds, can cause ‘tangles’ in the brain characteristic of some forms of dementia. Additionally, lack of sleep may hamper the brain’s ability to rid itself of toxins.

The amount of sleep was also linked differences in the structure of brain regions involved in cognitive processing and memory, again with greater changes associated with greater than or less than seven hours of sleep.

Consistently getting seven hours’ sleep each night was also important to cognitive performance and good mental health and wellbeing. Interrupted sleep patterns have previously been shown to be associated with increased inflammation, indicating a susceptibility to age-related diseases in older people.

Professor Jianfeng Feng from Fudan University in China said: “While we can’t say conclusively that too little or too much sleep causes cognitive problems, our analysis looking at individuals over a longer period of time appears to support this idea. But the reasons why older people have poorer sleep appear to be complex, influenced by a combination of our genetic makeup and the structure of our brains.”

The researchers say the findings suggest that insufficient or excessive sleep duration may be a risk factor for cognitive decline in ageing. This is supported by previous studies that have reported a link between sleep duration and the risk of developing Alzheimer’s disease and dementia, in which cognitive decline is a hallmark symptom.

Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge, one of the study’s authors, said: “Getting a good night’s sleep is important at all stages of life, but particularly as we age. Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and wellbeing and avoiding cognitive decline, particularly for patients with psychiatric disorders and dementias.”

Source: University of Cambridge

Categories : Environmental EffectsTags :

New Evidence-based Recommendations for Light Exposure

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For the first time, a set of recommendations have been drawn up to provide guidance for human exposure to light throughout the day and at nighttime, based on the amount of blue light in the environment. The recommendations are detailed in PLOS Biology.

Modern lifestyles, with 24-hour access to electric light and reduced exposure to natural daylight, can disrupt sleep and negatively impact health, well-being, and productivity. A new report in PLOS Biology addresses the issue of exactly how bright lighting should be during the day and in the evening to support healthy body rhythms, restful sleep, and daytime alertness.

An international body of leading scientific experts was brought together to draw up the first evidence-based, consensus recommendations for healthy daytime, evening, and nighttime light exposure. These recommendations provide much needed guidance to the lighting and electronics industries to aid the design of healthier environments and to improve how we light our workplaces, public buildings, and homes.

The new report took on a key question – how to properly measure the extent to which different types of lighting might influence circadian rhythms and sleep patterns. Light affects these patterns via a specialised type of cell in the eye that uses a light sensitive protein, melanopsin, that is distinct from the opsin in the rods and cones that support vision (and upon which traditional ways of measuring “brightness” are based). Since melanopsin is most sensitive to blue-cyan light, the new recommendations used a newly-developed light measurement standard tailored to this unique property: melanopic equivalent daylight illuminance. Analysis of data from a variety of studies proved that this new measurement approach could provide a reliable way of predicting the effects of light on human physiology and body rhythms, and so could form the basis of widely applicable and meaningful recommendations.

A crucial next step will be to integrate the recommendations into formal lighting guidelines, which currently focus on visual requirements rather than effects on health and well-being. Additionally, advances in LED lighting technology and the availability of low-cost light sensors are expected to increase the ease with which individuals can optimise their personal light exposure to best support their own circadian rhythms in line with the new recommendations.

Professor Timothy Brown, who brought the international exports together for the report added: “These recommendations provide the first scientific consensus, quantitative, guidance for appropriate daily patterns of light exposure to support healthy body rhythms, nighttime sleep and daytime alertness. This now provides a clear framework to inform how we light any interior space ranging from workplaces, educational establishments and healthcare facilities to our own homes.”

Source: Science Daily

Categories : Metabolic DisordersTags :

Moderate Light Levels During Sleep Increases Insulin Resistance

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Even exposure to moderate light levels during nighttime sleep, compared to sleeping in a dimly lit room, harms cardiovascular function during sleep and increases insulin resistance the following morning, according to a new study published in PNAS.

“The results from this study demonstrate that just a single night of exposure to moderate room lighting during sleep can impair glucose and cardiovascular regulation, which are risk factors for heart disease, diabetes and metabolic syndrome,” said senior study author Dr Phyllis Zee at Northwestern University. “It’s important for people to avoid or minimise the amount of light exposure during sleep.”

There is evidence that daytime light exposure increases heart rate via sympathetic nervous system activation, increasing heart rate and alertness to meet the day’s challenges.

“Our results indicate that a similar effect is also present when exposure to light occurs during nighttime sleep,” Dr Zee said.

“We showed your heart rate increases when you sleep in a moderately lit room,” said Dr Daniela Grimaldi, a co-first author and research assistant professor of neurology at Northwestern. “Even though you are asleep, your autonomic nervous system is activated. That’s bad. Usually, your heart rate together with other cardiovascular parameters are lower at night and higher during the day.”

The sympathetic and parasympathetic nervous systems regulate the body physiology during the day and night. Sympathetic takes charge during the day and parasympathetic is supposed to at night, when it conveys restoration to the entire body.

The researchers found signs of insulin resistance the morning after people slept in a light room. An earlier study examined a large population of healthy people who had exposure to light during sleep, and found they were more overweight and obese, Dr Zee said.

“Now we are showing a mechanism that might be fundamental to explain why this happens. We show it’s affecting your ability to regulate glucose,” Dr Zee said.

The study participants were unaware of the biological shift in their bodies at night.

“But the brain senses it,” A/Prof Grimaldi said. “It acts like the brain of somebody whose sleep is light and fragmented. The sleep physiology is not resting the way it’s supposed to.”

Night-time exposure to artificial light is widespread in the modern world, either from light-emitting devices indoors, or from outdoor sources such as street lights. Up to 40% of people sleep with a bedside lamp on or with a light on in the bedroom and/or keep the television on.

“In addition to sleep, nutrition and exercise, light exposure during the daytime is an important factor for health, but during the night we show that even modest intensity of light can impair measures of heart and endocrine health,” said co-first author Dr Ivy Mason.

The study tested the effect of sleeping with 100 lux (moderate light) compared to 3 lux (dim light) in participants over a single night. Moderate light exposure caused the body to go into sympathetic activation. In blood vessels, sympathetic activation constricts arteries and arterioles which increases vascular resistance and decreases distal blood flow. When this occurs throughout the body, the increased vascular resistance causes arterial pressure to increase.

“These findings are important particularly for those living in modern societies where exposure to indoor and outdoor nighttime light is increasingly widespread,” Dr Zee said.

Zee’s top tips for reducing light during sleep

1) Keep lights off. If a light is necessary (eg for older people’s safety), keep it dim and close to the floor.

2) Colour is important: amber or red/orange light stimulates the brain. Avoid white or blue light.

3) Blackout shades or eye masks are good if outdoor light can’t be controlled. Move your bed so the outdoor light isn’t shining on your face

As a rule of thumb, Dr Zee said that being able to see things really well means it’s too light.

Source: Northwestern University

Categories : General InterestTags :

How Detrimental to Sleep is Media Use Before Bedtime?

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A new study published in the Journal of Sleep Research found a complicated relationship between media use and bedtime and sleep quality and duration, with short, simple media use resulting in earlier bedtime and longer sleep duration.

Many factors contribute to sleep disturbance among young adults. Use of media is increasing rapidly, and little is known regarding its association with sleep disturbance. Previous research showed that social media use before bedtime in young adults resulted in reduced and poorer quality sleep.

The study examined how sleep might be impacted by media use – such as watching movies, television, or YouTube videos; browsing the Internet; or listening to music – before bed.

In the study, 58 adults kept a diary that recorded information related to time spent with media before bed, location of use, and multitasking. Electroencephalography captured parameters such as bedtime, total sleep time, and sleep quality. 

Media use in the hour before sleep was associated with an earlier bedtime. If the before-bed use did not involve multitasking and was conducted in bed, it was also associated with more total sleep time. A long use of media associated with later bedtime and less total sleep time.

Sleep quality, operationalised as the percent of total sleep time spent in N3 and REM sleep, was unaffected by media use before bed.

“If you are going to use media, like watching TV or listening to music, before bed, keep it a short, focused session and you are unlikely to experience any negative outcomes in your sleep that night,” said lead author Morgan Ellithorpe, PhD, of the University of Delaware.

Source: Wiley

Categories : Metabolic DisordersTags :

Getting Adequate Sleep Results in Reduced Calorie Intake

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Getting adequate sleep could be key to fighting growing rates of obesity around the world, according to a study published in JAMA Internal Medicine, which focused solely on improving sleep duration in overweight individuals.

Understanding the underlying causes of obesity and how to prevent it is the best way to fight obesity, according to first author Dr Esra Tasali. “The current obesity epidemic, according to experts, is mostly explained by an increase in caloric intake, rather than lack of exercise,” she said.

In a randomised clinical trial with 80 adults, published in JAMA Internal Medicine, researchers found that young, overweight adults who habitually slept fewer than 6.5 hours a night were able to sleep for 1.2 hours longer after a personalised sleep hygiene counselling session. The sleep intervention was intended to extend time in bed duration to 8.5 hours and, compared to controls, the increased sleep duration also reduced participants’ overall caloric intake by an average of 270 kcal (calories) per day.

“Over the years, we and others have shown that sleep restriction has an effect on appetite regulation that leads to increased food intake, and thus puts you at risk for weight gain over time,” said Tasali. “More recently, the question that everyone was asking was, ‘Well, if this is what happens with sleep loss, can we extend sleep and reverse some of these adverse outcomes?”

The study examines the effects of sleep extension on caloric intake but also does so in a real-world setting, with no influence on participants’ diets. Participants slept in their own beds, tracked their sleep with wearable devices, and otherwise followed their normal lifestyle without any instructions on diet or exercise.

“Most other studies on this topic in labs are short-lived, for a couple of days, and food intake is measured by how much participants consume from an offered diet,” said Tasali. “In our study, we only manipulated sleep, and had the participants eat whatever they wanted, with no food logging or anything else to track their nutrition by themselves.”

Instead, to objectively track participants’ caloric intake, investigators relied on the “doubly labelled water” method to track change in energy stores, which uses isotopes of hydrogen and oxygen in drinking water. “This is considered the gold standard for objectively measuring daily energy expenditure in a non-laboratory, real-world setting and it has changed the way human obesity is studied,” said Professor Dale A. Schoeller, senior study author and pioneer of the method.

Overall, individuals who increased their sleep duration were able to reduce their caloric intake by an average of 270 kcal per day – which would translate to roughly 12 kg of weight loss over three years if the effects were maintained over a long term.

Perhaps the most surprising aspect of the study was the intervention’s simplicity. “We saw that after just a single sleep counselling session, participants could change their bedtime habits enough to lead to an increase in sleep duration,” said Dr Tasali. “We simply coached each individual on good sleep hygiene, and discussed their own personal sleep environments, providing tailored advice on changes they could make to improve their sleep duration. Importantly, to blind participants to sleep intervention, recruitment materials did not mention sleep intervention, allowing us to capture true habitual sleep patterns at baseline.”

Even though the study did not systematically assess factors that may have influenced sleep behaviour, “limiting the use of electronic devices before bedtime appeared as a key intervention,” said Dr Tasali.

Following just a single counselling session, participants increased their average sleep duration by over an hour a night. Despite prescribing no other lifestyle changes, most participants had a large decrease in how much they ate, with some participants’ intake reduced by 500kcal per day.

The subjects were only involved in the study for a total of four weeks, with two weeks for gathering baseline information about sleep and caloric intake, followed by two weeks to monitor the effects of the sleep intervention.

“This was not a weight-loss study,” said Dr Tasali. “But even within just two weeks, we have quantified evidence showing a decrease in caloric intake and a negative energy balance – caloric intake is less than calories burned. If healthy sleep habits are maintained over longer duration, this would lead to clinically important weight loss over time. Many people are working hard to find ways to decrease their caloric intake to lose weight – well, just by sleeping more, you may be able to reduce it substantially.”

Source: University of Chicago Medicine

Categories : NeurologyTags :

Prompts During Sleep Boosts Recall of Names and Faces

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Hearing names repeated during deep sleep may help bolster recall of names and faces, according to new research from Northwestern University.

The researchers found that people’s name recall improved significantly when memories of newly learned face-name associations were reactivated while they were napping. Uninterrupted deep sleep was key in this improvement.

“It’s a new and exciting finding about sleep, because it tells us that the way information is reactivated during sleep to improve memory storage is linked with high-quality sleep,” said lead author Nathan Whitmore, a PhD candidate in the Interdepartmental Neuroscience Program at Northwestern University.

The research is reported in the Nature partner journal npj Science of Learning.

The three main stages of the experiment of Whitmore et al. (2022). First, participants learned 80 face-name associations. Next, they slept while EEG was monitored to determine sleep stage, and 20 of the spoken names were presented softly over background music during slow-wave sleep. Finally, memory testing showed superior memory due to memory reactivation during sleep, but only when sleep was undisturbed by sound presentations. Credit: Nathan Whitmore, a Ph.D. candidate in the Interdepartmental Neuroscience Program at Northwestern University.

The results also highlighted the importance of adequate sleep: for study participants with EEG measurements that indicated disrupted sleep, the memory reactivation had no effect and may even be detrimental. But in those with uninterrupted sleep during the specific times of sound presentations, the reactivation helped participants recall just over 1.5 more names.

The study recruited 24 participants, aged 18-31 years old, who were asked to memorise the faces and names of 40 pupils from a hypothetical Latin American history class and another 40 from a Japanese history class. When each face was presented again, they were asked to recall the associated name. After the learning exercise, participants took a nap while the researchers carefully monitored brain activity using EEG measurements. When participants reached the N3 “deep sleep” state, some of the names were softly played on a speaker with music that was associated with one of the classes.

When participants awoke, they were again tested on recognising faces and recalling their names.

According to the researchers, the finding on the relationship between sleep disruption and memory accuracy is noteworthy for several reasons.

“We already know that some sleep disorders like apnoea can impair memory,” said Whitmore. “Our research suggests a potential explanation for this—frequent sleep interruptions at night might be degrading memory.”

The lab is currently exploring the reactivation of memories and deliberately disrupting sleep in order to learn more about the relevant brain mechanisms.

Source: EurekAlert!

Categories : Respiratory DiseasesTags :

Melatonin May be The Culprit for Nocturnal Asthma

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Why patients with asthma find their condition worsens at night has remained largely unknown, but now researchers have found that the sleep hormone melatonin may be the culprit.

In ‘nocturnal asthma’ , patients with asthma often experience a worsening of asthmatic symptoms at night. More than 50% of asthma deaths occur at night, showing a link between nocturnal asthma symptoms and asthma deaths. Though numerous triggers that explain the pathogenesis of nocturnal asthma have been described, the precise mechanisms regulating this asthma phenotype remain obscured until now. Now, a study published in the American Journal of Physiology Lung Cellular and Molecular Physiology may have explained the relationship via melatonin.

Asthma patients suffer from bronchoconstriction which may be eased with a bronchodilator. However, melatonin, which is often prescribed for insomnia, favours a state of bronchoconstriction and weakens the relaxing effect of a bronchodilator through the activation of the melatonin MT2 receptor.

To elucidate this, the research group identified the expression of the melatonin MT2 receptor in human airway smooth muscle. They observed that the activation of the melatonin MT2 receptor with higher doses of melatonin or melatonin receptor agonist ramelteon greatly potentiated the bronchoconstriction. In addition, melatonin attenuated the relaxing effects of the widely used bronchodilator β-adrenoceptor agonist.

“Although serum concentration of melatonin did not significantly induce the airway constriction, greater doses of melatonin, which is clinically used to treat insomnia, jet lag, or cancer, worsened asthma symptoms and impaired the therapeutic effect of bronchodilators,” said study leader Kentaro Mizuta from Tohoku University Graduate School of Dentistry .

First author Haruka Sasaki added, “The pharmacological therapy that blocks the melatonin MT2 receptor could inhibit the detrimental effects of melatonin on airways.”

Source: Tohoku University