Rest and napping القيلولة

وَمِنۡ ءَايَٰتِهِۦ مَنَامُكُم بِٱلَّيۡلِ وَٱلنَّهَارِ وَٱبۡتِغَآؤُكُم مِّن فَضۡلِهِۦٓۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَسۡمَعُونَ

Among His signs are your sleep, by night and by day, and your seeking His bounty. There truly are signs in this for those who can hear

هُوَ ٱلَّذِي جَعَلَ لَكُمُ ٱلَّيۡلَ لِتَسۡكُنُواْ فِيهِ وَٱلنَّهَارَ مُبۡصِرًاۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَسۡمَعُونَ

It is He who made the night so that you can rest in it and the daylight so that you can see- there truly are signs in this for those who hear

وَمِن رَّحۡمَتِهِۦ جَعَلَ لَكُمُ ٱلَّيۡلَ وَٱلنَّهَارَ لِتَسۡكُنُواْ فِيهِ وَلِتَبۡتَغُواْ مِن فَضۡلِهِۦ وَلَعَلَّكُمۡ تَشۡكُرُونَ

In His mercy He has given you night and day, so that you may rest and seek His bounty and be grateful.’

وَمِنۡ ءَايَٰتِهِۦٓ أَنۡ خَلَقَ لَكُم مِّنۡ أَنفُسِكُمۡ أَزۡوَٰجࣰ ا لِّتَسۡكُنُوٓاْ إِلَيۡهَا وَجَعَلَ بَيۡنَكُم مَّوَدَّةࣰ وَرَحۡمَةًۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَتَفَكَّرُونَ

Another of His signs is that He created spouses from among yourselves for you to live with in tranquillity: He ordained love and kindness between you. There truly are signs in this for those who reflect

ٱللَّهُ ٱلَّذِي جَعَلَ لَكُمُ ٱلَّيۡلَ لِتَسۡكُنُواْ فِيهِ وَٱلنَّهَارَ مُبۡصِرًاۚ إِنَّ ٱللَّهَ لَذُو فَضۡلٍ عَلَى ٱلنَّاسِ وَلَٰكِنَّ أَكۡثَرَ ٱلنَّاسِ لَا يَشۡكُرُونَ

It is God who has given you the night in which to rest and the day in which to see. God is truly bountiful to people, but most people do not give thanks

And of His signs is your sleep by night and day by His will as a repose for you and your seeking during the day of His bounty in other words your going about freely in order to seek a living is by His will. Surely in that there are signs for people who listen listening in a way so as to be prompted to reflect and take heed.

And among His signs is the creation of the heavens and the earth, and the difference of your languages and colors. Verily, in that are indeed signs for men of sound knowledge (22)And among His signs is your sleep by night and by day, and your seeking His bounty. Verily, in that are indeed signs for a people who listen.) Allah sai (23) وَمِنْ آيَاتِهِ (And among His signs) indicating His magnificent power. خَلْقُ السَّمَاوَاتِ وَالْأَرْضِ (is the creation of the heavens and the earth,) The heavens with their vast height and brightness and beauty of the stars and planets, and the earth with its density and its mountains, valleys, seas, plains, animals and trees. وَاخْتِلَافُ أَلْسِنَتِكُمْ (and the difference of your languages) So, we see that some speak Arabic, and the Tatars have their own language, as do the Georgians, Romans, Franks, Berbers, Tou Couleurs (of Sudan), Ethiopians,

He it is Who made for you the night that you should rest therein and the day to see the attribution of sight ibsār to ‘the day’ is figurative since one is able to see during it. Surely in that are signs indications of His Oneness exalted be He for a folk who are able to hear hearing in such a way so as to reflect and be admonished.

And of His mercy exalted be He He has made for you night and day that you may rest therein in the night and that you may seek in the day of His bounty to earn your livelihood that perhaps you might give thanks’ for the grace of God during both of these times.

Do not grieve over their speech, for all power and honor belong to Allah. He is the All-Hearer, the All-Knower (65)Behold! Verily, to Allah belongs whosoever is in the heavens and whosoever is in the earth. And those who worship and invoke others besides Allah, in fact they follow not the partners, they follow only a conjecture and they do nothing but lie (66)He it is Who has appointed for you the night that you may rest therein, and the day to make things visible (to you). Verily, in this are Ayat for a people who listen (those who think deeply)(67) All Might and Honor is for Allah - He Alone has Full Authority within the Universe Allah said to His Messenger , وَلَا يَحْزُنكَ (Do not greive) because of the remarks of these idolators, and depend on Allah and ask for His help. Put your trust in Him. إِنَّ الْعِزَّةَ لِلَّهِ جَمِيعًا (For all power and honor belong to Allah.) All mig

Say: "Tell me! If Allah made the night continuous for you till the Day of Resurrection, which god besides Allah could bring you light? Will you not then hear? (71)Say: "Tell me! If Allah made the day continuous for you till the Day of Resurrection, which god besides Allah could bring you night wherein you rest? Will you not then see? (72)It is out of His mercy that He has made for you the night and the day that you may rest therein and that you may seek of His bounty – and in order that you may be grateful (73) Night and Day are among the Blessings of Allah and are Signs of Tawhid Allah reminds His servants of His favors towards them by subjugating for them the night and day, without which they could not survive. He explains that if He made the night continuous, lasting until the Day of Resurrection, that would be harmful for them and would cause boredom and stress. So He says: مَنْ إ

حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الأَسْوَدِ، قَالَ سَمِعْتُ جُنْدَبًا، يَقُولُ اشْتَكَى النَّبِيُّ صلى الله عليه وسلم فَلَمْ يَقُمْ لَيْلَةً أَوْ لَيْلَتَيْنِ‏.‏

Narrated Jundab:The Prophet (ﷺ) became sick and did not get up (for Tahajjud prayer) for a night or two

حَدَّثَنَا ابْنُ مُقَاتِلٍ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ هِنْدٍ بِنْتِ الْحَارِثِ، عَنْ أُمِّ سَلَمَةَ ـ رضى الله عنها ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم اسْتَيْقَظَ لَيْلَةً فَقَالَ ‏ "‏ سُبْحَانَ اللَّهِ مَاذَا أُنْزِلَ اللَّيْلَةَ مِنَ الْفِتْنَةِ، مَاذَا أُنْزِلَ مِنَ الْخَزَائِنِ مَنْ يُوقِظُ صَوَاحِبَ الْحُجُرَاتِ، يَا رُبَّ كَاسِيَةٍ فِي الدُّنْيَا عَارِيَةٍ فِي الآخِرَةِ ‏"‏‏.‏

Narrated Um Salama:One night the Prophet (ﷺ) got up and said, "Subhan Allah! How many afflictions Allah has revealed tonight and how many treasures have been sent down (disclosed). Go and wake the sleeping lady occupants of these dwellings up (for prayers), perhaps a well dressed in this world may be naked in the Hereafter

أَخْبَرَنَا الْعَبَّاسُ بْنُ عَبْدِ الْعَظِيمِ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ أَسْمَاءَ، قَالَ حَدَّثَنَا جُوَيْرِيَةُ بْنُ أَسْمَاءَ، عَنِ الْوَلِيدِ بْنِ أَبِي هِشَامٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ صَلُّوا فِي بُيُوتِكُمْ وَلاَ تَتَّخِذُوهَا قُبُورًا ‏"‏ ‏.‏

It was narrated from Nafi' that Abdullah bin Umar said:"Pray in your houses and do not make them like graves

أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا عَفَّانُ بْنُ مُسْلِمٍ، قَالَ حَدَّثَنَا وُهَيْبٌ، قَالَ سَمِعْتُ مُوسَى بْنَ عُقْبَةَ، قَالَ سَمِعْتُ أَبَا النَّضْرِ، يُحَدِّثُ عَنْ بُسْرِ بْنِ سَعِيدٍ، عَنْ زَيْدِ بْنِ ثَابِتٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم اتَّخَذَ حُجْرَةً فِي الْمَسْجِدِ مِنْ حَصِيرٍ فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم فِيهَا لَيَالِيَ حَتَّى اجْتَمَعَ إِلَيْهِ النَّاسُ ثُمَّ فَقَدُوا صَوْتَهُ لَيْلَةً فَظَنُّوا أَنَّهُ نَائِمٌ فَجَعَلَ بَعْضُهُمْ يَتَنَحْنَحُ لِيَخْرُجَ إِلَيْهِمْ فَقَالَ ‏ "‏ مَا زَالَ بِكُمُ الَّذِي رَأَيْتُ مِنْ صُنْعِكُمْ حَتَّى خَشِيتُ أَنْ يُكْتَبَ عَلَيْكُمْ وَلَوْ كُتِبَ عَلَيْكُمْ مَا قُمْتُمْ بِهِ فَصَلُّوا أَيُّهَا النَّاسُ فِي بُيُوتِكُمْ فَإِنَّ أَفْضَلَ صَلاَةِ الْمَرْءِ فِي بَيْتِهِ إِلاَّ الصَّلاَةَ الْمَكْتُوبَةَ ‏"‏ ‏.‏

It was narrated from Zaid bin Thabit that :The Prophet (ﷺ) used some palm fiber mats to section off a small area in the masjid. And the Messenger of Allah (ﷺ) prayed in it for several nights until the people gathered around him. Then, one night they did not hear his voice, and they thought that he was sleeping, so they cleared their throats to make him come out to them. He said: 'You kept doing that until I feared that it would be made obligatory for you, and if it were made obligatory, you would not be able to do it. O people, pray in your houses, for the best prayer a person offers is in his house, apart from the prescribed (obligatory) prayers

والثاني: القيلولة، فإنها مما تعين على قيام الليل، كما يعين السحور على صيام النهار، فإن نام فليجتهد في الانتباه قبل الزوال بقدر الاستعداد للصلاة قبل دخول الوقت.

ومنها: أن لا يترك القيلولة بالنهار، فإنها تعين على قيام الليل.

اعلم أن قيام الليل عسير على الخلق إلا على من وفق للقيام بشروطه الميسرة له ظاهرا وباطنا فأما الظاهرة فأربعة أمور الأول أن لا يكثر الأكل فيكثر الشرب فيغلبه النوم ويثقل عليه القيام كان بعض الشيوخ يقف على المائدة كل ليلة ويقول معاشر المريدين لا تأكلوا كثيرا فتشربوا كثيرا فترقدوا كثيرا فتتحسروا عند الموت كثيرا وهذا هو الأصل الكبير وهو تخفيف المعدة عن ثقل الطعام الثاني أن لا يتعب نفسه بالنهار في الاعمال التي تعيا بها الجوارح وتضعف بها الأعصاب فإن ذلك ايضا مجلبة للنوم الثالث أن لا يترك القيلولة بالنهار فإنها سنة للاستعانة على قيام الليل + حديث الاستعانة بقيلولة النهار على قيام الليل أخرجه ابن ماجه من حديث ابن عباس وقد تقدم + الرابع أن لا يحتقب الأوزار بالنهار فإن ذلك مما يقسى القلب ويحول بينه وبين أسباب الرحمة قال رجل للحسن يا أبا سعيد إني أبيت معافى وأحب قيام الليل وأعد طهوري فما بالي لا أقوم فقال ذنوبك قيدتك وكان الحسن رحمه الله إذا دخل السوق فسمع لغطهم ولغوهم يقول أظن أن ليل هؤلاء ليل سوء فإ

الورد الثالث من ضحوة النهار إلى الزوال ونعني بالضحوة المنتصف وما قبله بقليل وإن كان بعد كل ثلاث ساعات أمر بصلاة فإذا انقضى ثلاث ساعات بعد الطلوع فعندها وقبل مضيها صلاة الضحى فإذا مضت ثلاث ساعات أخرى فالظهر فإذا مضت ثلاث ساعات أخرى فالعصر فإذا مضت ثلاث أخرى فالمغرب ومنزلة الضحى بين الزوال والطلوع كمنزلة العصر بين الزوال والغروب إلا أن الضحى لم تفرض لأنه وقت انكباب الناس على أشغالهم فخفف عنهم الوظيفة الرابعة في هذا الوقت الأقسام الأربعة وزيد أمران أحدهما الاشتغال بالكسب وتدبير المعيشة وحضور السوق فإن كان تاجرا فينبغي أن يتجر بصدق وأمانة وإن كان صاحب صناعة فبنصح وشفقة ولا ينسى ذكر الله تعالى في جميع أشغاله ويقتصر من الكسب على قدر حاجته ليومه مهما قدر على أن يكتسب في كل يوم لقوته فإذا حصل كفاية يومه فليرجع إلى بيت ربه وليتزود لآخرته فإن الحاجة إلى زاد الآخرة أشد والتمتع به أدوم فاشتغاله بكسبه أهم من طلب الزيادة على حاجة الوقت فقد قيل لا يوجد المؤمن إلا في ثلاث مواطن مسجد يعمره أو بيت يستره أ

قال الله تعالى @QB@ ومن آياته منامكم بالليل والنهار @QE@

معينة على ما شرع الله سبحانه له من النكاح وملك اليمين من إعفاف الرجل نفسه وأهله فلا تطمح نفسه إلى سواها من الحرام ويعفها فلا تطمح نفسها إلى غيره وكلما كانت المحبة بين الزوجين أتم وأقوى كان هذا المقصود أتم وأكمل قال تعالى : @QB@ هو الذي خلقكم من @QE@ @QB@ نفس واحدة وجعل منها زوجها ليسكن إليها @QE@ وقال : @QB@ ومن آياته أن خلق لكم من أنفسكم أزواجا لتسكنوا إليها وجعل بينكم مودة ورحمة @QE@

Slow-wave sleep during a brief nap is related to reduced cognitive deficits during sleep deprivation.: Sleeping for a short period (i.e. napping) may help mitigate impairments in cognitive processing caused by sleep deprivation, but there is limited research on effects of brief naps in particular. Here, we tested the effect of a brief nap opportunity (30- or 60-min) during a period of sleep deprivation on two cognitive processes with broad scope, placekeeping and vigilant attention. In the evening, participants (N = 280) completed a placekeeping task (UNRAVEL) and a vigilant attention task (Psych

The effects of a mid-day nap on the neurocognitive performance of first-year medical residents: a controlled interventional pilot study.: Purpose: Despite shorter duty hours, fatigue remains a problem among medical residents. The authors tested the effect of a short, mid-day nap on the cognitive functioning and alertness of first-year internal medicine (IM) residents during normal duty hours. Method: This was a controlled, interventional study performed between July 2008 and April 2010. The authors recruited a nap group of 18 residents and a rest (control) group of 11 residents. Investigators connected all participants to an ambul

Night shifts in interns: Effects of daytime napping on autonomic activity and cognitive function.: Objective: Night shifts have adverse cognitive outcomes that might be attenuated by daytime napping. The neurovisceral integration model suggests that resting vagally mediated heart rate variability (vmHRV) is linked with cognitive function. This study investigated the relationship between resting vmHRV and cognitive function after different nap durations in interns after shift work. Methods: A total of 105 interns were randomly allocated to one of three groups (non-nap, n = 35; 15-min nap, n =

Optimising sleep and performance during night float: A systematic review of evidence and implications for graduate medical education trainees.: Graduate medical education (GME) training commonly requires residents and fellows to engage in night float shift work. This review aims to assess the effectiveness of interventions for trainees when preparing for, completing, and recovering from working night float shifts. We reviewed all available studies published prior to September 2019 using PubMed, Scopus, CINAHL, the Cochrane library, PsycINFO, and Google Scholar databases. We included all original, primary research articles assessing eith

Effects of napping on sleepiness and sleep-related performance deficits in night-shift workers: a systematic review.: Night-shift workers are prone to sleep deprivation, misalignment of circadian rhythms, and subsequent sleepiness and sleep-related performance deficits. The purpose of this narrative systematic review is to critically review and synthesize the scientific literature regarding improvements in sleepiness and sleep-related performance deficits following planned naps taken during work-shift hours by night workers and to recommend directions for future research and practice. We conducted a literature

Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials.: Objective: To estimate the association between daytime napping and cognitive and physical sport performance and fatigue after normal sleep and partial sleep deprivation (less sleep duration than necessary). Design: Systematic review and meta-analysis. Data sources: The PubMed, Scopus, Web of Science, Cochrane Central, SportDiscus and PsycINFO databases. Eligibility criteria for selecting studies: Randomised controlled trials on the effect of daytime napping on sport performance and fatigue avail

Circadian rhythms and disorders of the timing of sleep.

The daily alternation between sleep and wakefulness is one of the most dominant features of our lives and is a manifestation of the intrinsic 24 h rhythmicity underlying almost every aspect of our physiology. Circadian rhythms are generated by networks of molecular oscillators in the brain and peripheral tissues that interact with environmental and behavioural cycles to promote the occurrence of sleep during the environmental night. This alignment is often disturbed, however, by contemporary changes to our living environments, work or social schedules, patterns of light exposure, and biological factors, with consequences not only for sleep timing but also for our physical and mental health. Characterised by undesirable or irregular timing of sleep and wakefulness, in this Series paper we critically examine the existing categories of circadian rhythm sleep-wake disorders and the role of t…

matched on Wakefulness (mesh), Sleep (mesh)

Disturbance of the Circadian System in Shift Work and Its Health Impact.

The various non-standard schedules required of shift workers force abrupt changes in the timing of sleep and light-dark exposure. These changes result in disturbances of the endogenous circadian system and its misalignment with the environment. Simulated night-shift experiments and field-based studies with shift workers both indicate that the circadian system is resistant to adaptation from a day- to a night-oriented schedule, as determined by a lack of substantial phase shifts over multiple days in centrally controlled rhythms, such as those of melatonin and cortisol. There is evidence that disruption of the circadian system caused by night-shift work results not only in a misalignment between the circadian system and the external light-dark cycle, but also in a state of internal desynchronization between various levels of the circadian system. This is the case between rhythms controlle…

matched on Work Schedule Tolerance (mesh), Sleep (mesh)

Working Time Society consensus statements: Evidence-based effects of shift work on physical and mental health.

Potential effects of shift work on health are probably related to the misalignment between the light-dark cycle and the human activity-rest cycle. Light exposure at night mediates these effects, including social misalignment and leads to an inversion of activity and rest, which, in turn, is linked to changes in behaviours. This article reviews the epidemiological evidence on the association between shift work and health, and possible mechanisms underlying this association. First, evidence from findings of the meta-analyses and systematic reviews published in the last 10 yr is presented. In addition, it reports the larger single-occupation studies and recent large population-based studies of the general workforce. Koch's postulates were used to evaluate the evidence related to the development of disease as a result of exposure to shift work. Finally, we discussed limitations of the multip…

matched on Work Schedule Tolerance (mesh), Sleep (mesh)

Sleep and Nutrition Interactions: Implications for Athletes.

This narrative review explores the relationship between sleep and nutrition. Various nutritional interventions have been shown to improve sleep including high carbohydrate, high glycaemic index evening meals, melatonin, tryptophan rich protein, tart cherry juice, kiwifruit and micronutrients. Sleep disturbances and short sleep duration are behavioural risk factors for inflammation, associated with increased risk of illness and disease, which can be modified to promote sleep health. For sleep to have a restorative effect on the body, it must be of adequate duration and quality; particularly for athletes whose physical and mental recovery needs may be greater due to the high physiological and psychological demands placed on them during training and competition. Sleep has been shown to have a restorative effect on the immune system, the endocrine system, facilitate the recovery of the nervo…

matched on Athletic Performance (mesh), Sleep (mesh)

Circadian Rhythm Sleep-Wake Disorders in Older Adults.

The timing, duration, and consolidation of sleep result from the interaction of the circadian timing system with a sleep-wake homeostatic process. When aligned and functioning optimally, this allows wakefulness throughout the day and a long consolidated sleep episode at night. Mismatch between the desired timing of sleep and the ability to fall and remain asleep is a hallmark of the circadian rhythm sleep-wake disorders. This article discusses changes in circadian regulation of sleep with aging; how age influences the prevalence, diagnosis, and treatment of circadian rhythm sleep-wake disorders; and how neurologic diseases in older patients affect circadian rhythms and sleep.

matched on Wakefulness (mesh), Sleep (mesh)

The sleep-deprived human brain.

How does a lack of sleep affect our brains? In contrast to the benefits of sleep, frameworks exploring the impact of sleep loss are relatively lacking. Importantly, the effects of sleep deprivation (SD) do not simply reflect the absence of sleep and the benefits attributed to it; rather, they reflect the consequences of several additional factors, including extended wakefulness. With a focus on neuroimaging studies, we review the consequences of SD on attention and working memory, positive and negative emotion, and hippocampal learning. We explore how this evidence informs our mechanistic understanding of the known changes in cognition and emotion associated with SD, and the insights it provides regarding clinical conditions associated with sleep disruption.

matched on Wakefulness (mesh), Sleep Deprivation (mesh)

Circadian Rhythm Sleep-Wake Disorders.

Purpose of review: The endogenous circadian rhythms are one of the cardinal processes that control sleep. They are self-sustaining biological rhythms with a periodicity of approximately 24 hours that may be entrained by external zeitgebers (German for time givers), such as light, exercise, and meal times. This article discusses the physiology of the circadian rhythms, their relationship to neurologic disease, and the presentation and treatment of circadian rhythm sleep-wake disorders. Recent findings: Classic examples of circadian rhythms include cortisol and melatonin secretion, body temperature, and urine volume. More recently, the impact of circadian rhythm on several neurologic disorders has been investigated, such as the timing of occurrence of epileptic seizures as well as neurobehavioral functioning in dementia. Further updates include a more in-depth understanding of the symptoms…

matched on Wakefulness (mesh), Sleep (mesh)

Characteristics of shift work and their impact on employee performance and wellbeing: A literature review.

Objectives: To identify the characteristics of shift work that have an effect on employee's performance (including job performance, productivity, safety, quality of care delivered, errors, adverse events and client satisfaction) and wellbeing (including burnout, job satisfaction, absenteeism, intention to leave the job) in all sectors including healthcare. Design: A scoping review of the literature was undertaken. Data sources: We searched electronic databases (CINAHL, MEDLINE, PsychINFO, SCOPUS) to identify primary quantitative studies. Review methods: The search was conducted between January and March 2015. Studies were drawn from all occupational sectors (i.e. health and non health), meeting the inclusion criteria: involved participants aged ≥18 who have been working shifts or serve as control group for others working shifts, exploring the association of characteristics of shift work …

matched on Work Schedule Tolerance (mesh), Fatigue (mesh)

Health consequences of shift work and insufficient sleep.

This review summarises the literature on shift work and its relation to insufficient sleep, chronic diseases, and accidents. It is based on 38 meta-analyses and 24 systematic reviews, with additional narrative reviews and articles used for outlining possible mechanisms by which shift work may cause accidents and adverse health. Evidence shows that the effect of shift work on sleep mainly concerns acute sleep loss in connection with night shifts and early morning shifts. A link also exists between shift work and accidents, type 2 diabetes (relative risk range 1.09-1.40), weight gain, coronary heart disease (relative risk 1.23), stroke (relative risk 1.05), and cancer (relative risk range 1.01-1.32), although the original studies showed mixed results. The relations of shift work to cardiometabolic diseases and accidents mimic those with insufficient sleep. Laboratory studies indicate that …

matched on Work Schedule Tolerance (mesh), Sleep Deprivation (mesh)

Limbic thalamus and state-dependent behavior: The paraventricular nucleus of the thalamic midline as a node in circadian timing and sleep/wake-regulatory networks.

The paraventricular thalamic nucleus (PVT), the main component of the dorsal thalamic midline, receives multiple inputs from the brain stem and hypothalamus, and targets the medial prefrontal cortex, nucleus accumbens and amygdala. PVT has been implicated in several functions, especially adaptation to chronic stress, addiction behaviors and reward, mood, emotion. We here focus on the wiring and neuronal properties linking PVT with circadian timing and sleep/wake regulation, and their behavioral implications. PVT is interconnected with the master circadian pacemaker, the hypothalamic suprachiasmatic nucleus, receives direct and indirect photic input, is densely innervated by orexinergic neurons which play a key role in arousal and state transitions. Endowed with prominent wake-related Fos expression which is suppressed by sleep, and with intrinsic neuronal properties showing a diurnal osc…

matched on Wakefulness (mesh), Sleep (mesh)

The Consolidation and Transformation of Memory.

Memory consolidation refers to the transformation over time of experience-dependent internal representations and their neurobiological underpinnings. The process is assumed to be embodied in synaptic and cellular modifications at brain circuits in which the memory is initially encoded and to proceed by recurrent reactivations, both during wakefulness and during sleep, culminating in the distribution of information to additional locales and integration of new information into existing knowledge. We present snapshots of our current knowledge and gaps in knowledge concerning the progress of consolidation over time and the cognitive architecture that supports it and shapes our long-term memories.

matched on Wakefulness (mesh), Sleep (mesh)

Role of the basal ganglia in the control of sleep and wakefulness.

The basal ganglia (BG) act as a cohesive functional unit that regulates motor function, habit formation, and reward/addictive behaviors, but the debate has only recently started on how the BG maintain wakefulness and suppress sleep to achieve all these fundamental functions of the BG. Neurotoxic lesioning, pharmacological approaches, and the behavioral analyses of genetically modified animals revealed that the striatum and globus pallidus are important for the control of sleep and wakefulness. Here, we discuss anatomical and molecular mechanisms for sleep-wake regulation in the BG and propose a plausible model in which the nucleus accumbens integrates behavioral processes with wakefulness through adenosine and dopamine receptors.

matched on Wakefulness (mesh), Sleep (mesh)

Control of sleep and wakefulness.

This review summarizes the brain mechanisms controlling sleep and wakefulness. Wakefulness promoting systems cause low-voltage, fast activity in the electroencephalogram (EEG). Multiple interacting neurotransmitter systems in the brain stem, hypothalamus, and basal forebrain converge onto common effector systems in the thalamus and cortex. Sleep results from the inhibition of wake-promoting systems by homeostatic sleep factors such as adenosine and nitric oxide and GABAergic neurons in the preoptic area of the hypothalamus, resulting in large-amplitude, slow EEG oscillations. Local, activity-dependent factors modulate the amplitude and frequency of cortical slow oscillations. Non-rapid-eye-movement (NREM) sleep results in conservation of brain energy and facilitates memory consolidation through the modulation of synaptic weights. Rapid-eye-movement (REM) sleep results from the interactio…

matched on Wakefulness (mesh), Sleep (mesh)

The effects of Ramadan intermittent fasting on athletic performance: recommendations for the maintenance of physical fitness.

The behavioural modifications that accompany Ramadan intermittent fasting (RIF) are usually associated with some alterations in the metabolic, physiological, and psychological responses of athletes that may affect sport performance. Muslim athletes who are required to train and/or compete during the month-long, diurnal fast must adopt coping strategies that allow them to maintain physical fitness and motivation if they are to perform at the highest level. This updated review aims to present the current state of knowledge of the effects of RIF on training and performance, focusing on key-factors that contribute to the effects of Ramadan on exercise performance: energy restriction, sleep deprivation, circadian rhythm perturbation, dehydration, and alterations in the training load. The available literature contain few studies that have examined the effects of RIF on physical performance in …

matched on Athletic Performance (mesh), Sleep (mesh)

Dopamine in Drosophila: setting arousal thresholds in a miniature brain.

In mammals, the neurotransmitter dopamine (DA) modulates a variety of behaviours, although DA function is mostly associated with motor control and reward. In insects such as the fruitfly, Drosophila melanogaster, DA also modulates a wide array of behaviours, ranging from sleep and locomotion to courtship and learning. How can a single molecule play so many different roles? Adaptive changes within the DA system, anatomical specificity of action and effects on a variety of behaviours highlight the remarkable versatility of this neurotransmitter. Recent genetic and pharmacological manipulations of DA signalling in Drosophila have launched a surfeit of stories-each arguing for modulation of some aspect of the fly's waking (and sleeping) life. Although these stories often seem distinct and unrelated, there are some unifying themes underlying DA function and arousal states in this insect model…

matched on Wakefulness (mesh), Sleep (mesh)

Play it again: reactivation of waking experience and memory.

Episodic and spatial memories each involve the encoding of complex associations in hippocampal neuronal circuits. Such memory traces could be stabilised from short- to long-term forms by consolidation processes involving the 'reactivation' of the original network firing patterns during sleep and rest. Waking experience can be replayed in many different brain areas, but an important role for the hippocampus lies in the organisation of the 'reactivation' process. Emerging evidence suggests that sharp wave/ripple (SWR) events in the hippocampus could coordinate the reactivation of memory traces and direct their reinstatement in cortical circuits. Although the mechanisms remain uncertain, there is a growing consensus that such SWR-directed reactivation of brain-wide memory traces could underlie memory consolidation.

matched on Wakefulness (mesh), Sleep (mesh)

The memory function of sleep.

Sleep has been identified as a state that optimizes the consolidation of newly acquired information in memory, depending on the specific conditions of learning and the timing of sleep. Consolidation during sleep promotes both quantitative and qualitative changes of memory representations. Through specific patterns of neuromodulatory activity and electric field potential oscillations, slow-wave sleep (SWS) and rapid eye movement (REM) sleep support system consolidation and synaptic consolidation, respectively. During SWS, slow oscillations, spindles and ripples - at minimum cholinergic activity - coordinate the re-activation and redistribution of hippocampus-dependent memories to neocortical sites, whereas during REM sleep, local increases in plasticity-related immediate-early gene activity - at high cholinergic and theta activity - might favour the subsequent synaptic consolidation of me…

matched on Wakefulness (mesh), Sleep (mesh)

Functional neuroimaging insights into the physiology of human sleep.

Functional brain imaging has been used in humans to noninvasively investigate the neural mechanisms underlying the generation of sleep stages. On the one hand, REM sleep has been associated with the activation of the pons, thalamus, limbic areas, and temporo-occipital cortices, and the deactivation of prefrontal areas, in line with theories of REM sleep generation and dreaming properties. On the other hand, during non-REM (NREM) sleep, decreases in brain activity have been consistently found in the brainstem, thalamus, and in several cortical areas including the medial prefrontal cortex (MPFC), in agreement with a homeostatic need for brain energy recovery. Benefiting from a better temporal resolution, more recent studies have characterized the brain activations related to phasic events within specific sleep stages. In particular, they have demonstrated that NREM sleep oscillations (spin…

matched on Wakefulness (mesh), Sleep (mesh)

The orexin system: roles in sleep/wake regulation.

The neuropeptides orexin A and orexin B, produced in hypothalamic neurons, are critical regulators of sleep/wake states. Deficiency of orexin signaling results in narcoleptic phenotype in humans, dogs, and rodents. Recently, accumulating evidence has indicated that the orexin system regulates sleep and wakefulness through interactions with neuronal systems that are closely related with emotion, reward, and energy homeostasis. In this review, we will discuss the current understanding of the physiology of the orexin system especially focusing on its roles in the regulation of sleep/wakefulness states.

matched on Wakefulness (mesh), Sleep (mesh)

Antagonism of serotonergic 5-HT2A/2C receptors: mutual improvement of sleep, cognition and mood?

Serotonin [5-hydroxytryptamine (5-HT)] and 5-HT receptors are involved in sleep and in waking functions such as cognition and mood. Animal and human studies support a particular role for the 5-HT(2A) receptor in sleep, which has led to renewed interest in this receptor subtype as a target for the development of novel pharmacological agents to treat insomnia. Focusing primarily on findings in healthy human volunteers, a review of the available data suggests that antagonistic interaction with 5-HT(2A) receptors (and possibly also 5-HT(2C) receptors) prolongs the duration of slow wave sleep and enhances low-frequency (< 7 Hz) activity in the sleep electroencephalogram (EEG), a widely accepted marker of sleep intensity. Despite certain differences, the changes in sleep and the sleep EEG appear to be remarkably similar to those of physiologically more intense sleep after sleep deprivation. It…

matched on Wakefulness (mesh), Sleep (mesh)

Orexin neuronal circuitry: role in the regulation of sleep and wakefulness.

Orexin A and orexin B were initially identified as endogenous ligands for two orphan G protein-coupled receptors [104]. They were initially recognized as regulators of feeding behavior in view of their exclusive production in the lateral hypothalamic area (LHA), a region known as the feeding center, and their pharmacological activity [104,30,49,107]. Subsequently, the finding that orexin deficiency causes narcolepsy in humans and animals suggested that these hypothalamic neuropeptides play a critical role in regulating sleep/wake cycle [22,46,71,95,117]. These peptides activate waking-active monoaminergic and cholinergic neurons in the hypothalamus/brain stem regions to maintain a long, consolidated awake period. Recent studies on efferent and afferent systems of orexin neurons, and phenotypic characterization of genetically modified mice in the orexin system further suggested roles of o…

matched on Wakefulness (mesh), Sleep (mesh)

The roles of dopamine and serotonin, and of their receptors, in regulating sleep and waking.

Based on electrophysiological, neurochemical and neuropharmacological approaches, it is currently accepted that serotonin (5-HT) and dopamine (DA) function to promote waking (W) and to inhibit slow wave sleep (SWS) and/or rapid-eye-movement sleep (REMS). Serotonergic neurons of the dorsal raphe nucleus (DRN) fire at a steady rate during W, decrease their firing during SWS and virtually cease activity during REMS. On the other hand, DA cells in the ventral tegmental area (VTA) and the substantia nigra pars compacta (SNc) do not change their mean firing rate across the sleep-wake cycle. It has been proposed that DA cells in the midbrain show a change in temporal pattern rather than firing rate during the sleep-wake cycle. Available evidence tends to indicate that during W and REMS an increase of burst firing activity of DA neurons occurs together with an enhanced release of DA in the VTA, …

matched on Wakefulness (mesh), Sleep (mesh)

Do permanent night workers show circadian adjustment? A review based on the endogenous melatonin rhythm.

"Permanent" or "fixed" night shifts have been argued to offer a potential benefit over rotating shift systems in that they may serve to maximize circadian adjustment and hence minimize the various health and safety problems associated with night work. For this reason, some authors have argued in favor of permanent shift systems, but their arguments assume at least a substantial, if not complete, adjustment of the circadian clock. They have emphasized the finding that the day sleeps taken between successive night shifts by permanent night workers are rather longer than those of either slowly or rapidly rotating shift workers, but this could simply reflect increased pressure for sleep. The present paper reviews the literature on the adjustment to permanent night work of the circadian rhythm in the secretion of melatonin, which is generally considered to be the best known indicator of the s…

matched on Work Schedule Tolerance (mesh), Sleep (mesh)

Altered sleep-wake cycles and food intake: the Ramadan model.

In this review the effects of diurnal fasting on normal physiological processes are considered. Ramadan is placed in a circadian context, food and fluid ingestion being displaced to the pre-sunrise and post-sunset hours. Over the holy month, negative energy balance is often experienced, though this deficit is not a universal finding. Responses to exercise during the day show influences consistent with hypohydration and an increased reliance on fat as a source of fuel for exercise. Muscle performance and psychomotor performance are impaired as the month of fasting progresses but it is not clear how circadian rhythms in responses to activity are altered. For some measures at rest there is a reduction in amplitude and a delay in acrophase. Health-related benefits are reflected in a rise in high-density lipoprotein cholesterol and individuals with predispositions for coronary heart disease a…

matched on Wakefulness (mesh), Sleep (mesh)

Chronobiology of sleep in humans.

Periodic circadian (24-h) cycles play an important role in daily hormonal and behavioural rhythms. Usually our sleep/wake cycle, temperature and melatonin rhythms are internally synchronized with a stable phase relationship. When there is a desynchrony between the sleep/wake cycle and circadian rhythm, sleep disorders such as advanced and delayed sleep phase syndrome can arise as well as transient chronobiologic disturbances, for example from jet lag and shift work. Appropriately timed bright light is effective in re-timing the circadian rhythm and sleep pattern to a more desired time, ameliorating these disturbances. Other less potent retiming effects may also be obtained from the judicious use of melatonin and exercise.

matched on Work Schedule Tolerance (mesh), Sleep (mesh)