Pinpointing the cells that keep the body's master circadian clock ticking
A new mouse model helps researchers study the roles of cell types in keeping time inside the body
August 7, 2020
Science Daily/UT Southwestern Medical Center
UT Southwestern scientists have developed a genetically engineered mouse and imaging system that lets them visualize fluctuations in the circadian clocks of cell types in mice. The method, described online in the journal Neuron, gives new insight into which brain cells are important in maintaining the body's master circadian clock. But they say the approach will also be broadly useful for answering questions about the daily rhythms of cells throughout the body.
"This is a really important technical resource for advancing the study of circadian rhythms," says study leader Joseph Takahashi, Ph.D., chair of the department of neuroscience at UT Southwestern Medical Center, a member of UT Southwestern's Peter O'Donnell Jr. Brain Institute, and an investigator with the Howard Hughes Medical Institute (HHMI). "You can use these mice for many different applications."
Nearly every cell in humans -- and mice -- has an internal circadian clock that fluctuates on a roughly 24-hour cycle. These cells help dictate not only hunger and sleep cycles, but biological functions such as immunity and metabolism. Defects in the circadian clock have been linked to diseases including cancer, diabetes, and Alzheimer's, as well as sleep disorders. Scientists have long known that a small part of the brain -- called the suprachiasmatic nucleus (SCN) -- integrates information from the eyes about environmental light and dark cycles with the body's master clock. In turn, the SCN helps keep the rest of the cells in the body in sync with each other.
"What makes the SCN a very special kind of clock is that it's both robust and flexible," says Takahashi. "It's a very strong pacemaker that doesn't lose track of time, but at the same time can shift to adapt to seasons, changing day lengths, or travel between time zones."
To study the circadian clock in both the SCN and the rest of the body, Takahashi's research group previously developed a mouse that had a bioluminescent version of PER2 -- one of the key circadian proteins whose levels fluctuate over the course of a day. By watching the bioluminescence levels wax and wane, the researchers could see how PER2 cycled throughout the animals' bodies during the day. But the protein is present in nearly every part of the body, sometimes making it difficult to distinguish the difference in circadian cycles between different cell types mixed together in the same tissue.
"If you observe a brain slice, for instance, almost every single cell has a PER2 signal, so you can't really distinguish where any particular PER2 signal is coming from," says Takahashi.
In the new work, the scientists overcame this problem by turning to a new bioluminescence system that changed color -- from red to green -- only in cells that expressed a particular gene known as Cre. Then, the researchers could engineer mice so that Cre, which is not naturally found in mouse cells, was only present in one cell type at a time.
To test the utility of the approach, Takahashi and his colleagues studied two types of cells that make up the brain's SCN -- arginine vasopressin (AVP) and vasoactive intestinal polypeptide (VIP) cells. In the past, scientists have hypothesized that VIP neurons hold the key to keeping the rest of the SCN synchronized.
When the research team looked at VIP neurons -- expressing Cre in just those cells, so that PER2 luminesced green in VIP cells, while red elsewhere -- they found that removing circadian genes from the neurons had little overall effect on the circadian rhythms of the VIP neurons, or the rest of the SCN. "Even when VIP neurons no longer had a functioning clock, the rest of the SCN behaved essentially the same," explains Yongli Shan, Ph.D., a UTSW research scientist and lead author of the study. Nearby cells were able to signal to the VIP neurons to keep them in sync with the rest of the SCN, he says.
When they repeated the same experiment on AVP neurons, however -- removing key clock genes -- not only did AVP neurons themselves show disrupted rhythms, but the entire SCN stopped synchronously cycling on its usual 24-hour rhythm.
"What this showed us was that the clock in AVP neurons is really essential for the synchrony of the whole SCN network," says Shan. "That's a surprising result and somewhat counterintuitive, so we hope it leads to more work on AVP neurons going forward."
Takahashi says other researchers who study circadian rhythms have already requested the mouse line from his lab to study the daily cycles of other cells. The mice might allow scientists to hone in on the differences in circadian rhythms between cell types within a single organ, or how tumor cells cycle differently than healthy cells, he says.
"In all sorts of complex or diseased tissues, this can let you see which cells have rhythms and how they might be similar or different from the rhythms of other cell types."
https://www.sciencedaily.com/releases/2020/08/200807111938.htm
How Does Mental Health Affect Your Sleep?
Contributed By: Rose MacDowell, Sleepopolis
Expert Verified By: Dr. Nicole Moshfegh, Psy.D.
The term mental health describes emotional, cognitive, and social well-being. Mental health is important at every stage of life, from childhood and adolescence through adulthood. Mental health affects not just how we feel, but how we think and behave. Our psychological condition determines how we handle stress, relate to others, and make choices.
There are more than 200 types of mental illness, which is defined by the American Psychiatric Association as “a health condition involving changes in emotion, thinking, and behavior.” Mental illness is based in the brain and can have a significant impact on relationships and quality of life.
Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.
Mental Illness: Causes and Symptoms
Mental health problems can affect self-esteem, happiness, and basic functions, such as eating and sleeping. (1) Social and financial success is strongly influenced by psychological wellness, including self-awareness and our ability to exercise self-control.
Many factors contribute to mental health issues, including:
Genes and brain chemistry
Family history of mental health problems
Life experiences, such as trauma or abuse
Mental health issues run the gamut from minor difficulty with daily living to full-blown psychosis. Treatment can have a significant impact on the course and outlook of psychological issues, making early detection crucial.
Mental illness can appear in early childhood or not until adulthood. (2) Some psychological issues may not emerge until later in life and can be influenced by certain drugs and medical conditions. There are numerous warning signs of mental health issues. These vary depending on the nature of the condition, and may include:
Eating or sleeping too much or too little
Withdrawing from relationships and usual activities
Having low or no energy
Feeling numb
Experiencing unexplained aches and pains
Feeling helpless or hopeless
FAQ
Q: What is the most common mental illness?A: Depression, a mood disorder that affects 300 million people worldwide, is the single most common mental illness. Anxiety disorders are more prevalent overall.
Psychological difficulties increase the risk of troubled relationships with family and friends. (3) Interpersonal conflict can be caused by irritability and mood swings, or feelings such as fear and anger. Other cognitive signs associated with mental health issues include worry, confusion, memory loss, and intrusive thoughts.
More serious mental disorders may cause hallucinations, including hearing voices or believing things that are not true. Suicidal behavior or thoughts of harming another person are also common signs of psychological issues. A person suffering from mental illness may experience paranoia, imagined physical ailments, or the need to abuse drugs or alcohol.
Types of Mental Health Disorders
Each type of mood disorder is characterized by unique signs and symptoms and may co-occur with other disorders. For example, anxiety might occur along with substance abuse, physical complaints, or a sleep disorder like insomnia.
The following are some of the most common mental health disorders:
Anxiety Disorders. People with anxiety disorders respond to certain objects or situations with fear and dread. Anxiety disorders can include panic disorders, generalized anxiety disorder, and phobias. (4) Symptoms of anxiety include:
Fatigue
Feelings of restlessness or irritability
Difficulty focusing or learning new concepts
Chronic pain or muscle tension
Trouble controlling feelings of worry
Problems sleeping, including the inability to sleep, unsatisfying sleep, or excessive sleeping
Psychiatric Disorders in Children. Common psychiatric disorders in children include attention deficit hyperactivity disorder (ADHD) a neurodevelopmental disorder that usually persists into adulthood. Symptoms include impulsiveness, trouble focusing on tasks or conversations, restlessness, and feeling easily frustrated. Oppositional defiant disorder is part of a spectrum known as disruptive, impulse-control, and conduct disorders. Symptoms of oppositional defiant disorder include hostility toward and lack of cooperation with teachers, parents, and other authority figures. (5)
Eating Disorders. Eating disorders involve extreme emotions, attitudes, and behaviors related to weight and food. Common eating disorders include anorexia, bulimia, and binge eating.
Substance Use Disorders. Mental health problems and substance abuse disorders often occur together. (6) Substance abuse can be a cause or a result of psychiatric issues, and may be an attempt by some patients to self-medicate or reduce symptoms.
Mood Disorders. Almost one in ten people aged eighteen or older have a mood disorder. Mood disorders involve persistent feelings of sadness, or feelings that fluctuate between extreme happiness and extreme sadness. Mood disorders include:
Depression. Approximately 17.3 million people in the US — 7.1% of adults — suffered from one or more major depressive episodes in the last year. Depression is characterized by sadness and lack of usual enjoyment that continue for two weeks or longer. Grief and sadness related to a change in life circumstances are different from depression, which doesn’t improve in response to external events
Bipolar disorder. Bipolar disorder affects approximately six million adults in the US, and impacts men and women equally. The disorder is characterized by severe fluctuations in mood, behavior, and thought patterns. Fluctuations can last from a few hours to several months, and may be affected seasonal and light changes
Personality Disorders. People with personality disorders have inflexible personality traits that are distressing to the sufferer and may cause problems in work, school, or social relationships. (7) These disorders are highly resistant to treatment, and include the following:
Antisocial personality disorder, or APD. People with antisocial personality disorder exploit, manipulate, and disregard the feelings of others. APD describes the behavior of sociopaths and psychopaths. Psychopaths do not have a conscience, whereas sociopaths have a conscience that is severely disordered
Narcissistic personality disorder, or NPD. Approximately 1% of people are afflicted with NPD. The disorder is associated with lack of empathy, feelings of superiority, and a need for admiration. Narcissists tend to be easily hurt and are unable to tolerate criticism. Treatment is generally ineffective because people with NPD don’t believe they have a mental health issue
Borderline personality disorder, or BPD. People with borderline personality disorder have trouble regulating their emotions. They tend to act impulsively, resulting in career and relationship difficulties. Of the 1.4% of the population with BPD, 75% are women, though this number may represent misdiagnosis in many men with the disorder
Psychotic Disorders. Psychotic disorders are characterized by abnormal perceptions such as hallucinations and delusions. Hallucinations are false perceptions that involve hearing or seeing things that don’t exist. Delusions are false beliefs, such as being pursued by authorities or people wishing to do the sufferer harm. The most common psychotic disorder is schizophrenia, which typically appears in the mid to late twenties. Possible causes of schizophrenia include genetic and environmental factors, disordered brain circuitry, trauma, and drug abuse.
Psychosis
Psychosis describes mental conditions that involve loss of contact with reality.
Mental Health and Sleep
One common sign of mental health difficulty is trouble sleeping. (8) The sleep disorder most closely associated with psychiatric disturbances is chronic insomnia. Some common mental illnesses and their effect on sleep include the following:
Depression. Clinical depression often presents with persistent insomnia, or the inability to sleep. (9) Hypersomnia, or excessive drowsiness, can be a sign of depression, as well. Sleep disorders are associated so strongly with depression that some medical practitioners advise caution in diagnosing depression in patients without symptoms of a sleep disorder. Up to 75% of people diagnosed with depression also suffer from insomnia.
Bipolar Disorder. Bipolar disorder is strongly associated with the inability to fall asleep, stay asleep, fall back to sleep, or all three. People in the manic phase of bipolar disorder often have difficulty sleeping, whereas those in the depressive phase may sleep much more than usual. Studies show that sleep deprivation can aggravate the struggles with emotional regulation that are common in people who are bipolar. (10) For many sufferers, trouble sleeping can be an indication of an approaching manic phase.
Anxiety Disorder. Anxiety is a principal cause of chronic insomnia. Even common anxiety related to work and life circumstances may trigger insomnia. A primary cause of chronic insomnia is conditioned anxiety related to sleep and the bedtime routine. Anxiety’s impact on the body includes hyperactivity of the central nervous system and excessive release of stress hormones, such as adrenaline and cortisol. Studies show a strong association between a history of insomnia and anxiety disorder, panic disorder, and social anxiety disorder. (11)
Borderline Personality Disorder. BPD sufferers with insomnia typically experience the daytime consequences of sleep loss, including sleepiness, difficulty concentrating, and irritability. Symptoms of BPD can be worsened by insomnia, leading to a vicious cycle of sleeplessness and behavioral issues.
Personality Disorders. Some personality disorders may be associated with disturbed sleep patterns. (12) One study revealed that people with circadian rhythm disorder are more likely to have a personality disorder than people with normal sleep and wake cycles.
Psychotic Disorders. Psychotic disorders such as schizophrenia can have a profound impact on sleep. Sleep disturbances are often an early sign of schizophrenia and can precede psychiatric symptoms by months or years. Schizophrenia patients are more likely to suffer from other sleep disorders, as well, including:
Obstructive sleep apnea
Restless legs syndrome
Periodic limb movement disorder
Circadian rhythm dysfunction
FAQ
Q: What is circadian rhythm dysfunction?A: Circadian rhythm dysfunction is caused by a loss of synchronization between sleep-wake cycles and natural light and darkness signals. Symptoms include the inability to fall or stay asleep, cognitive dysfunction, and trouble maintaining a traditional sleep schedule.
Does Depression Cause Insomnia, or Vice Versa?
It was once thought that insomnia symptoms resulted from psychiatric disorders and depression, not the other way around. Now the evidence isn’t so clear. Sleep problems may not just be the result of emotional disturbances, they may increase the likelihood of suffering from them, as well.
Medications to treat psychiatric disturbances may also cause insomnia. Psychotropic medications can have stimulating effects that contribute to interrupted sleep. Restless leg syndrome and periodic limb movements may be triggered or exacerbated by antidepressants and other drugs used to treat mood disorders.
An analysis of major studies revealed that volunteers who suffered from insomnia symptoms were twice as likely to be diagnosed with depression as those without sleep difficulties. Why? Though the connection between mood disorders and insomnia isn’t entirely understood, it is well-known that hormones and neurotransmitters are affected by poor sleep. Sleep is a restorative activity that reduces stress in the body and areas of the brain, especially the axis between the hypothalamus and adrenal and pituitary glands. Excess secretion of cortisol — also known as “the stress hormone” — may play a role, as well.
Lack of sleep and the resulting physiological stress may predispose insomnia sufferers to major mood disturbances, making early treatment of sleep disorders essential, especially in people with a family history of mental health issues. (13)
Depression and Other Sleep Disorders
Insomnia is not the only sleep disorder associated with depression and anxiety. (14) Sleep apnea is a common cause of depression, as is hypersomnia. Sleep apnea is characterized by blockage of the airway and repeated awakenings during the night. Chronic sleep apnea can result in weight gain, increased risk of heart attack and stroke, and memory problems.
Hypersomnia is associated with excessive time spent sleeping and daytime sleepiness. The disorder can be caused by medical conditions, certain drugs, and immune system dysfunction. Though most people need between seven and nine hours of sleep each night, the need for significantly more can indicate a mood disorder. Like sleep apnea, hypersomnia is related to a greater likelihood of heart attack and stroke.
Hypersomnia
A sleep disorder associated with excessive sleeping. Hypersomnia includes narcolepsy, an autoimmune disease that can cause extreme sleepiness and muscle weakness.
Psychiatric Medications and Sleep
Medications to treat psychological disturbances can have a positive or negative impact on sleep. (15) Most antidepressant medications influence the neurotransmitters dopamine, serotonin, and norepinephrine, all of which help to regulate sleep and wake cycles. Some can have stimulating effects that contribute to insomnia.
Restless legs syndrome and periodic limb movements can be triggered or exacerbated by antidepressants and other drugs used to treat mood disorders. (16) These medications can be helpful in patients without movement-related sleep disorders who suffer from hypersomnia.
Other medications such as older tricyclic drugs can help establish healthy sleep patterns in depressed patients with insomnia. Once a depressed patient starts taking medication, insomnia may be the last symptom to improve. Newer antidepressants such as selective serotonin reuptake inhibitors can suppress the REM stage of sleep, as well as the vivid dreaming that occurs during REM sleep.
Antipsychotic medications can help with insomnia, a common issue for schizophrenia sufferers. Some of these drugs can also cause daytime sleepiness, which may be preferable to insomnia. (17) Hypnotic medications are often prescribed along with antipsychotics, and may initially help with insomnia due to their sedative effects. However, many patients become tolerant of hypnotics or develop a rebound response, which can limit their usefulness for insomnia over the long-term.
Suicidal Behavior and Sleep
Suicidal behavior is a common feature of certain psychiatric conditions, including bipolar disorder and depression. Suicidal thoughts and actions can also occur in the absence of a psychiatric condition. Suicide is the second leading cause of death in people between 15 and 24. Suicide is more likely to be completed by people with access to guns.
Signs of suicidal thoughts and behavior may include the following:
Speaking about suicide or the desire to die
Feeling or talking about feeling hopeless
Researching ways to commit suicide
Appearing anxious or depressed
Excessive use of alcohol, or use of drugs
Exhibiting unusual behavior, such as rage, mood swings, or agitation
Suicidal behavior is often caused by psychiatric conditions, but may also be triggered by difficult life events, stress, loss of a loved one, or past trauma such as emotional, physical, or sexual abuse. Suicidal behavior is also more common in people suffering from post-traumatic stress disorder or chronic pain.
Recent research reveals that suicidal behavior and lack of sufficient sleep are related in adolescents and adults. (18) People who completed their suicidal actions were more likely to have suffered from insomnia, hypersomnia, or another sleep disturbance. Though further research is needed to better understand this link, existing studies reveal a strong association between mental health and sleep.
FAQ
Q: What is suicidal ideation?A: Suicidal ideation involves thinking about, planning, or considering suicide.
Last Word From Sleepopolis
Mental health is critically important to happiness and well-being. Research reveals a connection between mental illness and disturbed sleep, an association that may exist months or years before psychiatric symptoms appear.
Medications and other mental health treatments can help regulate sleep patterns, but may also cause or worsen insomnia, hypersomnia, and other sleep difficulties. Adjustment of medications or separate treatment of sleep issues can help establish healthy sleep patterns and improve quality of life for people suffering from mental health disorders.
References
Amy C. Watson, Self-Stigma in People With Mental Illness, Schizophrenia Bulletin, January 25, 2007
William Copeland Ph.D., Cumulative Prevalence of Psychiatric Disorders by Young Adulthood: A Prospective Cohort Analysis From the Great Smoky Mountains Study, Journal of the American Academy of Child & Adolescent Psychiatry, March 2011
Alan R. Teo, Social Relationships and Depression: Ten-Year Follow-Up from a Nationally Representative Study, Plos One, April 30, 2013
Peter J. Norton, Transdiagnostic models of anxiety disorder: Theoretical and empirical underpinnings, Clinical Psychology Review, August 2017
Martin B. Keller, MD, The Disruptive Behavioral Disorder in Children and Adolescents: Comorbidity and Clinical Course, Journal of the American Academy of Child & Adolescent Psychiatry, March 1992
Robert E Drake, et al. A systematic review of psychosocial research on psychosocial interventions for people with co-occurring severe mental and substance use disorders, Journal of Substance Abuse Treatment, January 2008
Tyrer P, Mulder R, Crawford M, Newton-Howes G, Simonsen E, Ndetei D, Koldobsky N, Fossati A, Mbatia J, Barrett B., Personality disorder: a new global perspective, World Psychiatry, February 2010
Krahn LE., Psychiatric disorders associated with disturbed sleep, Seminars in Neurology, March 25, 2005
Chiara Baglioni et al., Insomnia as a predictor of depression: A meta-analytic evaluation of longitudinal epidemiological studies, Journal of Affective Disorders, December 2011
Harvey AG, Talbot LS, Gershon A, Sleep Disturbance in Bipolar Disorder Across the Lifespan, Clinical Psychology, New York State Psychiatric Institute, April 8, 2012
Heidemarie Blumenthal, et al., The Links Between Social Anxiety Disorder, Insomnia Symptoms, and Alcohol Use Disorders: Findings From a Large Sample of Adolescents in the United States, Behavior Therapy, January 2019
Yaron Dagan, High prevalence of personality disorders among Circadian Rhythm Sleep Disorders (CRSD) patients, Journal of Psychosomatic Research, October 1996
Liu X, Buysse DJ, Gentzler AL, Kiss E, Mayer L, Kapornai K, Vetró A, Kovacs M., Insomnia and hypersomnia associated with depressive phenomenology and comorbidity in childhood depression, Sleep, January 30, 2007
Nutt D, Wilson S, Paterson L., Sleep disorders as core symptoms of depression, Dialogues in Clinical Neuroscience, September 2008
DeMartinis NA, Winokur A., Effects of psychiatric medications on sleep and sleep disorders, CNS and Neurological Disorders Drug Targets, February 6, 2007
Staner L., Sleep disturbances, psychiatric disorders, and psychotropic drugs, Dialogues in Clincal Neuroscience, December 7, 2005
Waite F, Myers E, Harvey AG, Espie CA, Startup H, Sheaves B, Freeman D., Treating Sleep Problems in Patients with Schizophrenia, Behavioural and Cognitive Psychotherapy, May 2016
Goldstein TR, Bridge JA, Brent DA., Sleep Disturbance Preceding Completed Suicide in Adolescents, Journal of Consulting and Clinical Psychology, February 17, 2010
Original article: https://sleepopolis.com/education/how-does-mental-health-affect-your-sleep/
Rose MacDowell
Rose is the Chief Research Officer at Sleepopolis, which allows her to indulge her twin passions for dense scientific studies and writing about health and wellness. An incurable night owl, she loves discovering the latest information about sleep and how to get (lots) more of it. She is a published novelist who has written everything from an article about cheese factories to clock-in instructions for assembly line workers in Belgium. One of her favorite parts of her job is connecting with the best sleep experts in the industry and utilizing their wealth of knowledge in the pieces she writes. She enjoys creating engaging articles that make a difference in people’s lives. Her writing has been reviewed by The Boston Globe, Cosmopolitan, and the Associated Press, and received a starred review in Publishers Weekly. When she isn’t musing about sleep, she’s usually at the gym, eating extremely spicy food, or wishing she were snowboarding in her native Colorado. Active though she is, she considers staying in bed until noon on Sundays to be important research.
Brain activity intensity drives need for sleep
September 16, 2019
Science Daily/University College London
The intensity of brain activity during the day, notwithstanding how long we've been awake, appears to increase our need for sleep, according to a new UCL study in zebrafish.
The research, published in Neuron, found a gene that responds to brain activity in order to coordinate the need for sleep. It helps shed new light on how sleep is regulated in the brain.
"There are two systems regulating sleep: the circadian and homeostatic systems. We understand the circadian system pretty well -- our built-in 24-hour clock that times our biological rhythms, including sleep cycles, and we know where in the brain this rhythm is generated," explained lead author Dr Jason Rihel (UCL Cell & Developmental Biology).
"But the homeostatic system, which causes us to feel increasingly tired after a very long day or sleepless night, is not well understood. What we've found is that it appears to be driven not just by how long you've been awake for, but how intensive your brain activity has been since you last slept."
To understand what processes in the brain drive homeostatic sleep regulation -- independent of time of day -- the research team studied zebrafish larvae.
Zebrafish are commonly used in biomedical research, partly due to their near-transparent bodies that facilitate imaging, in addition to similarities to humans such as sleeping every night.
The researchers facilitated an increase in brain activity of the zebrafish using various stimulants including caffeine.
Those zebrafish which had drug-induced increased brain activity slept for longer after the drugs had worn off, confirming that the increase in brain activity contributed to a greater need for sleep.
The researchers found that one specific area of the zebrafish brain was central to the effect on sleep pressure: a brain area that is comparable to a human brain area found in the hypothalamus, known to be active during sleep. In the zebrafish brain area, one specific brain signalling molecule called galanin was particularly active during recovery sleep, but did not play as big a role in regular overnight sleep.
To confirm that the drug-induced findings were relevant to actual sleep deprivation, the researchers conducted a test where they kept the young zebrafish awake all night on a 'treadmill' where the fish were shown moving stripes -- by imitating fast-flowing water, this gives the fish the impression that they need to keep swimming. The zebrafish that were kept awake slept more the next day, and their brains showed an increase in galanin activity during recovery sleep.
The findings suggest that galanin neurons may be tracking total brain activity, but further research is needed to clarify how they detect what's going on across the whole brain.
The researchers say their finding that excess brain activity can increase the need for sleep might explain why people often feel exhausted after a seizure.
"Our findings may also shed light on how some animals can avoid sleep under certain conditions such as starvation or mating season -- it may be that their brains are able to minimise brain activity to limit the need for sleep," said the study's first author, Dr Sabine Reichert (UCL Cell & Developmental Biology).
The researchers say that by discovering a gene that plays a central role in homeostatic sleep regulation, their findings may help to understand sleep disorders and conditions that impair sleep, such as Alzheimer's disease.
"We may have identified a good drug target for sleep disorders, as it may be possible to develop therapies that act on galanin," added Dr Reichert.
https://www.sciencedaily.com/releases/2019/09/190916110556.htm
Sleep interrupted: What's keeping us up at night?
August 6, 2019
Science Daily/Florida Atlantic University
One of the largest longitudinal studies to date examined evening consumption of alcohol, caffeine and nicotine among an African-American cohort and objectively measured sleep outcomes in their natural environments instead of laboratory or observatory settings. The study involved 785 participants and totaled 5,164 days of concurrent actigraphy and daily sleep diaries that recorded how much alcohol, caffeine or nicotine they consumed within four hours of bedtime. Results may be good news for coffee lovers, bad news for smokers.
Between 50 to 70 million Americans have a sleep disorder. Sleepless nights are associated with a number of adverse health outcomes including heart disease, high blood pressure, diabetes, and certain cancers. Evening use of alcohol, caffeine and nicotine are believed to sabotage sleep. Yet, studies examining their effects on sleep are limited by small sample sizes that don't represent racial and ethnic diversity or objective measures of sleep. Furthermore, these investigations have been conducted in laboratory or observatory settings.
Considering the public health importance of getting a good night's sleep and the widespread use of these substances, relatively few studies have thoroughly investigated the association between evening use of alcohol, caffeine and nicotine and sleep parameters.
A study led by a researcher at Florida Atlantic University with collaborators from Brigham and Women's Hospital, Harvard T. H Chan School of Public Health, Harvard Medical School, Emory University the National Institutes of Health, and the University of Mississippi Medical Center, is one of the largest longitudinal investigations to date to examine evening consumption of alcohol, caffeine and nicotine among an African-American cohort with objectively measured sleep outcomes in their natural environments.
Using actigraphy (wrist-watch-like sensor) and concurrent daily sleep diaries, the researchers examined the night-to-night associations of evening use of alcohol, caffeine and nicotine on sleep duration, sleep efficiency and wake after sleep onset. The study involved 785 participants and totaled 5,164 days of concurrent actigraphy and daily sleep diaries that recorded how much alcohol, caffeine or nicotine they consumed within four hours of bedtime.
Results of the study, published in the journal Sleep, may be good news for coffee lovers. The researchers did not find an association between consumption of caffeine within four hours of bedtime with any of the sleep parameters. However, the researchers warn that caffeine dosing, and individual variations in caffeine sensitivity and tolerance, were not able to be measured and can play an important role in the association between caffeine use and sleep.
For smokers and those who enjoy "Happy Hour" or an alcoholic beverage with dinner, the study shows that a night with use of nicotine and/or alcohol within four hours of bedtime demonstrated worse sleep continuity than a night without these substances, even after controlling for age, gender, obesity, level of education, having work/school the next day, and depressive symptoms, anxiety, and stress.
Nicotine was the substance most strongly associated with sleep disruption and yet another reason to quit smoking. There was a statistically significant interaction between evening nicotine use and insomnia in relation to sleep duration. Among participants with insomnia, nightly nicotine use was associated with an average 42.47-minute reduction in sleep duration. The effects of nicotine may be particularly significant among individuals with insomnia.
The results from this study are especially meaningful as they were observed in individuals unselected for sleep problems and who generally had high sleep efficiency. Moreover, they were based on longitudinal data so that the associations can take account of not only between-person differences but also within-person variations in exposures and covariates such as age, obesity, educational attainment, having work/school the next day, and mental health symptomatology.
"African Americans have been underrepresented in studies examining the associations of nicotine, alcohol, and caffeine use on sleep," said Christine E. Spadola, Ph.D., lead author and an assistant professor in FAU's Phyllis and Harvey Sandler School of Social Work within the College for Design and Social Inquiry. "This is especially significant because African Americans are more likely to experience short sleep duration and fragmented sleep compared to non-Hispanic Whites, as well as more deleterious health consequences associated with inadequate sleep than other racial or ethnic groups."
These findings support the importance of sleep health recommendations that promote the restriction of evening alcohol and nicotine use to improve sleep continuity.
https://www.sciencedaily.com/releases/2019/08/190806101604.htm
Neural sleep patterns emerged at least 450 million years ago
July 10, 2019
Science Daily/Stanford Medicine
Researchers at the Stanford University School of Medicine have found that neural signatures in sleeping zebrafish are analogous to those of humans, suggesting that the brain activity evolved at least 450 million years ago, before any creatures crawled out of the ocean.
Scientists have known for more than 100 years that fish enter a sleeplike state, but until now they didn't know if their sleep resembled that of land animals.
The researchers found that when zebrafish sleep, they can display two states that are similar to those found in mammals, reptiles and birds: slow-wave sleep and paradoxical, or rapid eye movement, sleep. The discovery marks the first time these brain patterns have been recorded in fish.
"This moves the evolution of neural signatures of sleep back quite a few years," said postdoctoral scholar Louis Leung, PhD.
A paper describing the research will be published July 10 in Nature. Philippe Mourrain, PhD, associate professor of psychiatry and behavioral sciences, is the senior author. Leung is the lead author.
To study the zebrafish, common aquarium dwellers also known as danios, the researchers built a benchtop fluorescent light-sheet microscope capable of full-fish-body imaging with single-cell resolution. They recorded brain activity while the fish slept in an agar solution that immobilized them. They also observed the heart rate, eye movement and muscle tone of the sleeping fish using a fluorescence-based polysomnography that they developed.
They named the sleep states they observed "slow-bursting sleep," which is analogous to slow-wave sleep, and "propagating-wave sleep," analogous to REM sleep. Though the fish don't move their eyes during REM sleep, the brain and muscle signatures are similar. (Fish also don't close their eyes when they sleep, as they have no eyelids.)
Sleeping like the fish
The researchers found another similarity between fish and human sleep. By genetically disrupting the function of melanin-concentrating hormone, a peptide that governs the sleep-wake cycle, and observing neural expressions as the fish slept, the researchers determined that the hormone's signaling regulates the fish's propagating wave sleep the way it regulates REM sleep in mammals.
Other aspects of their sleep state are similar to those of land vertebrates, Mourrain said: The fish remain still, their muscles relax, their cardio-respiratory rhythms slow down and they fail to react when they're approached.
"They lose muscle tone, their heartbeat drops, they don't respond to stimuli -- the only real difference is a lack of rapid eye movement during REM sleep," Mourrain said, though he added, "The rapid movement of the eyes is not a good criterion of this state, and we prefer to call it paradoxical sleep, as the brain looks awake while one is asleep."
While scientists can't say for certain that all animals sleep, it appears to be a universal need among vertebrates and invertebrates. Animals will die if they are deprived of sleep long enough, and people who fail to receive adequate sleep suffer from mental problems such as memory lapses and impaired judgment, along with a higher risk of disorders such as obesity and high blood pressure.
The exact benefits of sleep are still a mystery, however. "It's an essential function," Mourrain said, "but we don't know precisely what it does."
He added that sleep disorders are linked to most neurological disorders such as autism spectrum disorders, Fragile X syndrome, and Alzheimer's and Parkinson's disease. "Sleep disturbances are an aggravating factor of these disorders," Mourrain said. It is critical to develop this animal model to study sleep functions at the cellular level, including neuronal connectivity and DNA repair, and in turn understand the pathophysiological consequences of sleep disruptions, he added.
The discovery means sleep research can be conducted on zebrafish, which are easy to study, in part because they're transparent. They breed quickly, are inexpensive to care for and are just over an inch long. Drug testing requires only the addition of chemicals to their water.
"Because the fish neural signatures are in essence the same as ours, we can use information about them to generate new leads for drug trials," Leung said. He added that mice, often a stand-in for human research, are nocturnal and a less relevant model for our sleep.
"As zebrafish are diurnal like humans, it's perhaps more biologically accurate to compare fish sleep with humans' for some aspects," Leung said.
https://www.sciencedaily.com/releases/2019/07/190710132015.htm
Common sleep myths compromise good sleep and health
April 16, 2019
Science Daily/NYU Langone Health / NYU School of Medicine
People often say they can get by on five or fewer hours of sleep, that snoring is harmless, and that having a drink helps you to fall asleep.
These are, in fact, among the most widely held myths about sleeping that not only shape poor habits, but may also pose a significant public health threat, according to a new study publishing online in Sleep Health on April 16.
Researchers from NYU School of Medicine reviewed more than 8,000 websites to identify the 20 most common assumptions about sleep. With a team of sleep medicine experts, they ranked them based on whether each could be dispelled as a myth or supported by scientific evidence, and on the harm that the myth could cause.
"Sleep is a vital part of life that affects our productivity, mood, and general health and well-being," says study lead investigator, Rebecca Robbins, PhD, a postdoctoral research fellow in the Department of Population Health at NYU Langone Health. "Dispelling myths about sleep promotes healthier sleep habits which, in turn, promote overall better health."
The claim by some people that they can get by on five hours of sleep was among the top myths researchers were able to dispel based on scientific evidence. They say this myth also poses the most serious risk to health from long-term sleep deficits. To avoid the effects of this falsehood and others identified in this study, such as the value of taking naps when you routinely have difficulty sleeping overnight, Robbins and her colleagues suggest creating a consistent sleep schedule and spending more time, at least seven hours, asleep.
Another common myth relates to snoring. And while Robbins says snoring can be harmless, it can also be a sign of sleep apnea, a potentially serious sleep disorder in which breathing starts and stops over the course of the night. The authors encourage patients not to dismiss loud snoring, but rather to see a doctor since this sleep behavior may lead to heart stoppages or other illnesses.
The study authors also found sufficient evidence in published studies that, despite beliefs to the contrary, drinking alcoholic beverages before bed is indeed unhealthy for sleep. According to experts, alcohol reduces the body's ability to achieve deep sleep, which people need to function properly.
"Sleep is important to health, and there needs to be greater effort to inform the public regarding this important public health issue," says study senior investigator Girardin Jean Louis, PhD, a professor in the departments of Population Health and Psychiatry at NYU Langone. "For example, by discussing sleep habits with their patients, doctors can help prevent sleep myths from increasing risks for heart disease, obesity, and diabetes."
The researchers acknowledge that some myths still cause disagreement among sleep experts. For instance, although sleeping in on weekends does disrupt the natural circadian rhythm, for people in certain professions, such as shift workers, it may be better for them to sleep in than to get fewer hours of sleep overall. These discrepancies, they say, suggest that further research needs to be done.
https://www.sciencedaily.com/releases/2019/04/190416081414.htm
Does extra sleep on the weekends repay your sleep debt? No, researchers say
February 28, 2019
Science Daily/Cell Press
Insufficient sleep and untreated sleep disorders put people at increased risk for metabolic problems, including obesity and diabetes. But is extra sleep on the weekends enough to reduce those risks? The short answer, according to new findings is 'no.'
"The key take-home message from this study is that ad libitum weekend recovery or catch-up sleep does not appear to be an effective countermeasure strategy to reverse sleep loss induced disruptions of metabolism," says Kenneth Wright of the University of Colorado Boulder.
People often sleep more on weekends than they do during the week. Yet it wasn't known how returning to an insufficient sleep schedule during the workweek after a weekend of recovery sleep influences a person's metabolic health.
To find out, in the new study, researchers led by Christopher Depner and Wright enlisted healthy young adults. Each participant was randomly assigned to one of three groups. The first had plenty of time to sleep -- 9 hours -- each night for 9 nights. The second had just 5 hours to sleep each night over that same period. Finally, the third slept 5 hours for 5 days followed by a weekend in which they slept as much as they liked before returning to another 2 days of restricted sleep.
In the two sleep-restricted groups, insufficient sleep led to an increase in snacking after dinner and weight gain. During ad libitum weekend recovery sleep in the third group, study participants slept an hour longer on average than they usually would. They also consumed fewer extra calories after dinner than those who got insufficient sleep.
However, when they went back to getting insufficient sleep after the weekend, their circadian body clock was timed later. They also ate more after dinner as their weight continued to rise.
The sleep restriction in the first group of participants was associated with a decrease in insulin sensitivity of about 13 percent. But the group that had a chance to sleep more on the weekend still showed less sensitivity to insulin. The insulin sensitivity of their whole bodies, liver, and muscle decreased by 9 to 27 percent after they got insufficient sleep again, once the weekend was over.
"Our findings show that muscle- and liver-specific insulin sensitivity were worse in subjects who had weekend recovery sleep," Depner says, noting that those metabolic aberrations weren't seen in the people who got less sleep all along. "This finding was not anticipated and further shows that weekend recovery sleep is not likely [to be] an effective sleep-loss countermeasure regarding metabolic health when sleep loss is chronic."
The Sleep Research Society and American Academy of Sleep Medicine recommends 7 or more hours of sleep nightly for adults, to promote optimal health. The new findings add to evidence that insufficient sleep is a risk factor for metabolic disorders. It also shows that catching up on weekends isn't the solution to chronic sleep loss during the week.
Wright says that it's not yet clear whether weekend recovery sleep can be an effective health countermeasure for people who get too little sleep only occasionally -- a night or two per week, perhaps. They hope to explore the fine details of these dynamics in future studies, including the influence of daytime napping and other strategies for getting more Zzzs.
https://www.sciencedaily.com/releases/2019/02/190228113534.htm
Insufficient sleep associated with risky behavior in teens
Mental health issues, substance abuse, accidents more likely for high school students sleeping less than six hours per night
October 1, 2018
Science Daily/Brigham and Women's Hospital
Researchers examined a national data sample of risk-taking behaviors and sleep duration self-reported by high school students over eight years and found an association between sleep duration and personal safety risk-taking actions.
Adolescents require 8-10 hours of sleep at night for optimal health, according to sleep experts, yet more than 70 percent of high school students get less than that. Previous studies have demonstrated that insufficient slsleep eep in youth can result in learning difficulties, impaired judgement, and risk of adverse health behaviors. In a new study, researchers at Brigham and Women's Hospital examined a national data sample of risk-taking behaviors and sleep duration self-reported by high school students over eight years and found an association between sleep duration and personal safety risk-taking actions. Results are published in a JAMA Pediatrics research letter on October 1.
"We found the odds of unsafe behavior by high school students increased significantly with fewer hours of sleep," said lead author Mathew Weaver, PhD, research fellow, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital. "Personal risk-taking behaviors are common precursors to accidents and suicides, which are the leading causes of death among teens and have important implications for the health and safety of high school students nationally."
Compared to students who reported sleeping eight hours at night, high school students who slept less than six hours were twice as likely to self-report using alcohol, tobacco, marijuana or other drugs, and driving after drinking alcohol. They were also nearly twice as likely to report carrying a weapon or being in a fight. Researchers found the strongest associations were related to mood and self- harm. Those who slept less than six hours were more than three times as likely to consider or attempt suicide, and four times as likely to attempt suicide, resulting in treatment. Only 30 percent of the students in the study reported averaging more than eight hours of sleep on school nights.
The Youth Risk Behavior Surveys are administered biannually by the U.S. Centers for Disease Control and Prevention (CDC) at public and private schools across the country. Researchers used data from 67,615 high school students collected between 2007 and 2015. Personal safety risk-taking behaviors were examined individually and as composite categories. All analyses were weighted to account for the complex survey design and controlled for age, sex, race, and year of survey in mathematical models to test the association between sleep duration and each outcome of interest.
"Insufficient sleep in youth raises multiple public health concerns, including mental health, substance abuse, and motor vehicle crashes," said senior author Elizabeth Klerman, MD, PhD, director of the Analytic Modeling Unit, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital. "More research is needed to determine the specific relationships between sleep and personal safety risk-taking behaviors. We should support efforts to promote healthy sleep habits and decrease barriers to sufficient sleep in this vulnerable population."
https://www.sciencedaily.com/releases/2018/10/181001114300.htm
Sleep disorder linked with changes to brain structure typical of dementia
July 4, 2018
Science Daily/European Lung Foundation
Obstructive sleep apnea is associated with changes to the structure of the brain that are also seen in the early stages of dementia, according to a new study.
OSA, where the walls of the throat relax and narrow during sleep stopping breathing, is known to reduce levels of oxygen in the blood. The new study suggests that this drop in oxygen may be linked to a shrinking of the brain's temporal lobes and a corresponding decline in memory.
The researchers say the study provides evidence that screening older people for OSA and giving treatment where needed could help prevent dementia in this population.
The study was led by Professor Sharon Naismith from the University of Sydney, Australia. She said: "Between 30 and 50% of the risk for dementia is due to modifiable factors, such as depression, high blood pressure, obesity and smoking. In recent years, researchers have recognised that various sleep disturbances are also risk factors for dementia. We wanted to look specifically at obstructive sleep apnoea and its effects on the brain and cognitive abilities."
The researchers worked with a group of 83 people, aged between 51 and 88 years, who had visited their doctor with concerns over their memory or mood but had no OSA diagnosis. Each participant was assessed for their memory skills and symptoms of depression, and each was given an MRI scan to measure the dimensions of different areas of the brain.
Participants also attended a sleep clinic where they were monitored overnight for signs of OSA using polysomnography. This technique records brain activity, levels of oxygen in the blood, heart rate, breathing and movements.
The researchers found that patients who had low levels of oxygen in their blood while they were sleeping tended to have reduced thickness in the left and right temporal lobes of the brain. These are regions known to be important in memory and affected in dementia.
They also found that this alteration in the brain was linked with participant's poorer ability to learn new information. The researchers say this is the first time a direct link of this kind has been shown.
Conversely, patients with signs of OSA were also more likely to have increased thickness in other regions of the brain, which the researchers say could be signs of the brain reacting to lower levels of oxygen with swelling and inflammation.
OSA is more common in older people and has already been linked with heart disease, stroke and cancer, but it can be treated with a continuous positive airway pressure (CPAP) device, which prevents the airway closing during sleep.
Professor Naismith added: "We chose to study this group because they are older and considered at risk of dementia. Our results suggest that we should be screening for OSA in older people. We should also be asking older patients attending sleep clinics about their memory and thinking skills, and carrying out tests where necessary.
"There is no cure for dementia so early intervention is key. On the other hand, we do have an effective treatment for OSA. This research shows that diagnosing and treating OSA could be an opportunity to prevent cognitive decline before it's too late."
Professor Naismith and her team are now working on research to find out whether CPAP treatment can prevent further cognitive decline and improve brain connectivity in patients with mild cognitive impairment.
Andrea Aliverti, Professor of Bioengineering at Politecnico di Milano, Italy, is Head of the European Respiratory Society's Assembly on Clinical Physiology and Sleep and was not involved in the research. He said: "We already know that as well as disrupting sleep, OSA can increase the risk of high blood pressure, type 2 diabetes, heart attack and stroke. This research adds to evidence that OSA is also linked to dementia and suggests a likely mechanism for the link. However, we can treat OSA and measures such as stopping smoking and losing weight can reduce the risk of developing the condition."
https://www.sciencedaily.com/releases/2018/07/180704194350.htm
Mid-afternoon slump? Why a sugar rush may not be the answer
Protein -- not sugar -- stimulates cells keeping us thin and awake, a new study suggests.
A new study has found that protein and not sugar activates the cells responsible for keeping us awake and burning calories. The research, published in the Nov. 17 issue of the scientific journal Neuron, has implications for understanding obesity and sleep disorders.
Wakefulness and energy expenditure rely on "orexin cells," which secrete a stimulant called orexin/hypocretin in the brain. Reduced activity in these unique cells results in narcolepsy and has been linked to weight gain.
Scientists at the University of Cambridge compared actions of different nutrients on orexin cells. They found that amino acids -- nutrients found in proteins such as egg whites -- stimulate orexin neurons much more than other nutrients.
"Sleep patterns, health, and body weight are intertwined. Shift work, as well as poor diet, can lead to obesity," said lead researcher Dr Denis Burdakov of the Department of Pharmacology and Institute of Metabolic Science. "Electrical impulses emitted by orexin cells stimulate wakefulness and tell the body to burn calories. We wondered whether dietary nutrients alter those impulses."
To explore this, the scientists highlighted the orexin cells (which are scarce and difficult to find) with genetically targeted fluorescence in mouse brains. They then introduced different nutrients, such as amino acid mixtures similar to egg whites, while tracking orexin cell impulses.
They discovered that amino acids stimulate orexin cells. Previous work by the group found that glucose blocks orexin cells (which was cited as a reason for after-meal sleepiness), and so the researchers also looked at interactions between sugar and protein. They found that amino acids stop glucose from blocking orexin cells (in other words, protein negated the effects of sugar on the cells).
These findings may shed light on previously unexplained observations showing that protein meals can make people feel less calm and more alert than carbohydrate meals.
"What is exciting is to have a rational way to 'tune' select brain cells to be more or less active by deciding what food to eat," Dr Burdakov said. "Not all brain cells are simply turned on by all nutrients, dietary composition is critical.
"To combat obesity and insomnia in today's society, we need more information on how diet affects sleep and appetite cells. For now, research suggests that if you have a choice between jam on toast, or egg whites on toast, go for the latter! Even though the two may contain the same number of calories, having a bit of protein will tell the body to burn more calories out of those consumed."
Sleep problems prevalent for military members
April 7, 2015
RAND Corporation
Improving the quality and quantity of US military members' sleep following deployment could help reduce other health problems, including depression and post-traumatic stress disorder, according to a new study.
However, a lack of consistent and transparent sleep-related policies may impede efforts to promote sleep health among service members, researchers say.
"The U.S. military has shifted from combat operations in Iraq and Afghanistan toward helping service members and veterans reintegrate into noncombat roles," said Wendy Troxel, co-leader of the study and a behavioral scientist at RAND, a nonprofit research organization. "One issue that is often overlooked once military men and women return home is that of persistent sleep problems, because in many ways such problems are viewed as endemic to military culture."
Sleep disturbances are a common reaction to stress and are linked to a host of physical and mental health problems. Sleep problems often follow a chronic course, persisting long after service members return home from combat, with consequences for their reintegration and the readiness and resiliency of the force, researchers say.
The RAND report is the first comprehensive review of sleep-related policies and programs across the U.S. Department of Defense, examining the frequency of sleep disorders and factors that contribute to the problem. A survey of nearly 2,000 service members from all branches of the U.S. military found sleep problems had negative effects on mental health, daytime functioning and perceived operational readiness.
"Military policies on prevention of sleep problems are lacking, and medical policies focus on treating mental disorders that are often linked with sleep problems, instead of sleep itself," said Regina Shih, project co-leader and a senior social scientist at RAND. "We know that sleep problems may precede the onset of mental disorders."
While there may be stigma about seeking sleep treatment, it may be lower than the stigma associated with seeking help for mental health problems. Researchers say this suggests sleep could be a gateway to improving psychological health and readiness in service members.
Researchers say that historically, military cultural attitudes have tended to discount the importance of sleep. For example, service members noted that depriving oneself of sleep is often seen as a badge of honor and acknowledging the need for sleep can be seen as a sign of weakness.
The study recommends widespread education and awareness programs within the Defense Department as one means of shifting these cultural attitudes. In operational contexts, the military emphasizes mission first and the need for sleep may be sacrificed for operational demands. Policies are needed to educate service members and leaders about the importance of sleep, including awareness on the importance of sleep for resilience.
Leaders are not always sure how to develop and execute sleep plans that can balance circadian rhythms with the realities of operational environments, or how to allow for adequate recovery periods after extended sleep deprivation in order to optimize force readiness.
The RAND study presents 16 policy recommendations to help the military improve the prevention, identification and treatment of sleep problems in service members. Those policies fall under four broad categories: prevention of sleep problems; increasing identification and diagnosis of sleep problems; ways to clinically manage sleep disorders and promote sleep health; and ways to improve sleep in training and operational contexts.
http://www.sciencedaily.com/releases/2015/04/150407095639.htm
Sleep disorders found to be highly prevalent in firefighters
November 13, 2014
Science Daily/Brigham and Women's Hospital
In a national sample of almost 7,000 firefighters, researchers examined the prevalence of common sleep disorders and their association with adverse health and safety outcomes and found that sleep disorders are highly prevalent, and associated with substantially increased risk of motor vehicle crashes and cardio-metabolic diseases among firefighters.
"Our findings demonstrate the impact of common sleep disorders on firefighter health and safety, and their connection to the two leading causes of death among firefighters," said Barger. "Unfortunately, more than 80 percent of firefighters who screened positive for a common sleep disorder were undiagnosed and untreated."
Researchers found that a total of 37.2 percent of firefighters screened positive for sleep disorders including obstructive sleep apnea, insomnia, shift work disorder and restless leg syndrome. Firefighters with a sleep disorder were more likely to report a motor vehicle crash and were more likely to report falling asleep while driving than those who did not screen positive. Additionally, firefighters with sleep disorders were more likely to report having cardiovascular disease, diabetes, depression and anxiety, and to report poorer health status, compared with those who did not screen positive.
http://www.sciencedaily.com/releases/2014/11/141113085220.htm
Well-being in later life: The mind plays an important role
July 7, 2017
Science Daily/Helmholtz Zentrum München - German Research Center for Environmental Health
Well-being in later life is largely dependent on psychosocial factors. Physical impairments tend to play a secondary role, as scientists have discovered.
"Aging itself is not inevitably associated with a decline in mood and quality of life," says Prof. Karl-Heinz Ladwig, summarizing the results. "It is rather the case that psychosocial factors such as depression or anxiety impair subjective well-being, the Head of the Mental Health Research Group at the Institute of Epidemiology II, Helmholtz Zentrum München and Professor of Psychosomatic Medicine at the TUM University Hospital explains. "And in the case of women, living alone also plays an important role."
"To date the impact of emotional stress has barely been investigated"
For the current study, Prof. Ladwig and his team relied on data derived from about 3,600 participats with an average age of 73 who had taken part in the population-based KORA-Age Study. "What made the study particularly interesting was the fact that the impact of stress on emotional well-being has barely been investigated in a broader, non-clinical context," explains PD Dr. Karoline Lukaschek, epidemiologist in the Mental Health Research Group and lead author of the paper. "Our study therefore explicitly included anxiety, depression and sleep disorders."
Generally high levels of well-being but...
To ascertain levels of subjective well-being, the scientists used a questionnaire devised by the World Health Organization (the WHO-5 Well-Being Index) with a score range of 0 to 100. For the purpose of analysis, they divided the respondents' results into two categories: 'high' (score > 50) and 'low' (score ? 50). The subsequent evaluation revealed a high level of subjective well-being in the majority (79 percent) of the respondents. The average values were also above the threshold set by the WHO. In the 'low' group, however, there was a conspicuously high number of women: about 24 percent compared to 18 percent for men.
Depression and anxiety disorders are the biggest risk
Trying to uncover the most important causes for subjective well-being, the scientists mainly identified psychosocial factors: above all, depression and anxiety disorders had the strongest effect on well-being. Low income and sleep disorders also had a negative effect. However, poor physical health (for example, low physical activity or so-called multimorbidity) seemed to have little impact on perceived life satisfaction. Among women, living alone also significantly increased the probability of a low sense of well-being.
"The findings of the current study clearly demonstrate that appropriate services and interventions can play a major role for older people, especially for older women living on their own," Prof. Ladwig says, categorizing the results. "And this is all the more important, given that we know that high levels of subjective well-being are linked to a lower mortality risk."
https://www.sciencedaily.com/releases/2017/07/170707095413.htm
Interrupted sleep impairs memory in mice
July 27, 2011
Science Daily/Stanford University Medical Center
With the novel use of a technique that uses light to control brain cells, researchers have shown that fragmented sleep causes memory impairment in mice.
Until recently scientists have been unable to tease out the effects on the brain of different yet intertwined features of sleep. But these investigators were able to overcome that problem and come to their findings by using the novel method, known as optogenetics, to manipulate brain cells to affect just one aspect of sleep.
The study shows that "regardless of the total amount of sleep, a minimal unit of uninterrupted sleep is crucial for memory consolidation," the authors write in the study that will be published online July 25 in the Proceedings of the National Academy of Sciences.
While the study does not reach any conclusions about the amount of sleep needed to avoid memory impairment in humans, it does suggest that memory difficulties in people with apnea and other sleep disorders are likely connected to the compromised continuity of sleep caused by such conditions.
http://www.sciencedaily.com/releases/2011/07/110725152844.htm
Sleep disorders affect men and women differently
Women are more likely to feel tired and depressed than men
May 23, 2017
Science Daily/American Academy of Sleep Medicine
A new study suggests that men and women are affected differently by sleep disorders. Results show that women are more likely than men to have more severe symptoms of depression, trouble sleeping at night, and excessive daytime sleepiness. Women also have a higher degree of difficulty concentrating and remembering things due to sleepiness or tiredness. In contrast, male snoring was more likely than female snoring to force bed partners to sleep in different rooms.
Results show that women are more likely than men to have more severe symptoms of depression, trouble sleeping at night, and excessive daytime sleepiness. Women also have a higher degree of difficulty concentrating and remembering things due to sleepiness or tiredness. In contrast, male snoring was more likely than female snoring to force bed partners to sleep in different rooms.
"We found that females were more likely to have sleeping disorders associated with daytime sleepiness," said co-author Dr. John Malouf, founder of SleepGP sleep clinic in Coolangatta, Queensland, Australia. "Females were also likely to feel more affected by the burden of their symptoms."
The main purpose of the study was to understand the differences in functional status between the sexes when they present to primary care providers with sleep problems.
"What was surprising about the results was that while men and women tended to present at a similar age, their symptoms and the effect on their lives differed markedly," said lead author Allegra Boccabella, research associate at SleepGP clinic. "We didn't expect there to be differences across the board in terms of the different aspects of people's lives."
Study results are published in the May 15 issue of the Journal of Clinical Sleep Medicine.
Boccabella and Malouf conducted a retrospective clinical audit of 744 patients who received sleep-related health care from 7 private general practices in Australia between April 2013 and January 2015. Patients completed a variety of sleep-related questionnaires, including the Epworth Sleepiness Scale (ESS), the Snoring Severity Scale (SSS), and the Functional Outcomes of Sleep Questionnaire 10.
According to the authors, understanding how the symptoms reported by women differ from those of men can help medical professionals manage sleep disorders more holistically.
"If we can identify the ways that their lives are affected, we can help produce better outcomes for the patient," said Boccabella.
Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/05/170523081838.htm