Circadian rhythm and light

قَالَ مُوسَىٰٓ أَتَقُولُونَ لِلۡحَقِّ لَمَّا جَآءَكُمۡۖ أَسِحۡرٌ هَٰذَا وَلَا يُفۡلِحُ ٱلسَّٰحِرُونَ

Moses said, ‘Is this what you say about the Truth when it comes to you? Is this sorcery? Sorcerers never prosper.’

فَلَمَّا جَآءَ ٱلسَّحَرَةُ قَالَ لَهُم مُّوسَىٰٓ أَلۡقُواْ مَآ أَنتُم مُّلۡقُونَ

When the sorcerers came, Moses said to them, ‘Throw down whatever you have.’

فَلَمَّآ أَلۡقَوۡاْ قَالَ مُوسَىٰ مَا جِئۡتُم بِهِ ٱلسِّحۡرُۖ إِنَّ ٱللَّهَ سَيُبۡطِلُهُۥٓ إِنَّ ٱللَّهَ لَا يُصۡلِحُ عَمَلَ ٱلۡمُفۡسِدِينَ

When they did so, Moses said, ‘Everything you have brought is sorcery and God will show it to be false. God does not make the work of mischief-makers right

وَٱتَّبَعُواْ مَا تَتۡلُواْ ٱلشَّيَٰطِينُ عَلَىٰ مُلۡكِ سُلَيۡمَٰنَۖ وَمَا كَفَرَ سُلَيۡمَٰنُ وَلَٰكِنَّ ٱلشَّيَٰطِينَ كَفَرُواْ يُعَلِّمُونَ ٱلنَّاسَ ٱلسِّحۡرَ وَمَآ أُنزِلَ عَلَى ٱلۡمَلَكَيۡنِ بِبَابِلَ هَٰرُوتَ وَمَٰرُوتَۚ وَمَا يُعَلِّمَانِ مِنۡ أَحَدٍ حَتَّىٰ يَقُولَآ إِنَّمَا نَحۡنُ فِتۡنَةࣱ فَلَا تَكۡفُرۡۖ فَيَتَعَلَّمُونَ مِنۡهُمَا مَا يُفَرِّقُونَ بِهِۦ بَيۡنَ ٱلۡمَرۡءِ وَزَوۡجِهِۦۚ وَمَا هُم بِضَآرِّينَ بِهِۦ مِنۡ أَحَدٍ إِلَّا بِإِذۡنِ ٱللَّهِۚ وَيَتَعَلَّمُونَ مَا يَضُرُّهُمۡ وَلَا يَنفَعُهُمۡۚ وَلَقَدۡ عَلِمُواْ لَمَنِ ٱشۡتَرَىٰهُ مَا لَهُۥ فِي ٱلۡأٓخِرَةِ مِنۡ خَلَٰقࣲۚ وَلَبِئۡسَ مَا شَرَوۡاْ بِهِۦٓ أَنفُسَهُمۡۚ لَوۡ كَانُواْ يَعۡلَمُونَ

and followed what the evil ones had fabricated about the Kingdom of Solomon instead. Not that Solomon himself was a disbeliever; it was the evil ones who were disbelievers. They taught people witchcraft and what was revealed in Babylon to the two angels Harut and Marut. Yet these two never taught anyone without first warning him, ‘We are sent only to tempt- do not disbelieve.’ From these two, they learned what can cause discord between man and wife, although they harm no one with it except by God’s leave. They learned what harmed them, not what benefited them, knowing full well that whoever gained [this knowledge] would lose any share in the Hereafter. Evil indeed is the [price] for which they sold their souls, if only they knew

وَجَآءَ ٱلسَّحَرَةُ فِرۡعَوۡنَ قَالُوٓاْ إِنَّ لَنَا لَأَجۡرًا إِن كُنَّا نَحۡنُ ٱلۡغَٰلِبِينَ

The sorcerers came to Pharaoh and said, ‘Shall we be rewarded if we win?’

وَأُلۡقِيَ ٱلسَّحَرَةُ سَٰجِدِينَ

The sorcerers fell to their knees

(And follow that which the devils falsely related against the kingdom of Solomon�) [2:102]. Muhammad ibn 'Abd al-'Aziz al-Qantari informed us> Abu'l-Fadl al-Haddadi> Abu Yazid al-Khalidi> Ishaq ibn Ibrahim> Jarir> Husayn ibn 'Abd al-Rahman> 'Imran ibn al-Harith who said: �Once as we were sitting with Ibn 'Abbas when he said: 'The devils used to eavesdrop on heaven. One of them would bring a word of truth from therein, and when he is trusted for telling the truth, he would add to it seventy lies with which he earns the hearts of people. When Solomon came to know about it, he took it and buried it beneath his throne. When he died, a devil stood in the street and said: 'Shall I guide you to Solomon's guarded treasure, the like of which he does not have?' They said: 'Yes, do'. He said: 'It is under his throne; go and unearth it'. They said: 'This is magic'. Different nations then copied it f

And they follow wa’ttaba‘ū is a supplement to nabadha ‘it cast away’ what the devils used to relate during the time of Solomon’s kingdom in the way of sorcery it is said that they the devils buried these books of sorcery underneath his throne when his kingdom was taken from him; it is also said that they used to listen stealthily and add fabrications to what they heard and then pass it on to the priests who would compile it in books; this would be disseminated and rumours spread that the jinn had knowledge of the Unseen. Solomon gathered these books and buried them. When he died the devils showed people where these books were and the latter brought them out and found that they contained sorcery and said ‘Your kingdom was only thanks to what is in here’; they then took to learning them and rejected the Scriptures of their prophets. In order to demonstrate Solomon’s innocence and in repudi

And the sorcerers came to Pharaoh saying ‘Surely a-inna read pronouncing both hamzas or by not pronouncing the second one but inserting an alif between the two in both cases there will be a wage for us if we are the victors?’

And the sorcerers fell down in prostration.

And so the sorcerers came to Fir'awn. They said: "Indeed there will be a (good) reward for us if we are the victors. (113)He said: "Yes, and moreover you will (in that case) be of the nearest (to me). (114) The Magicians convene and change Their Ropes into Snakes before Musa Allah describes the conversation that took place between Fir'awn and the magicians he collected to defeat Musa, peace be upon him. Fir'awn told them that he will reward them and give them tremendous provisions. He made them hope in acquiring what they wished for and to make them among his private audience and best associates. When they were assured of the cursed Fir'awn's promises,

And We revealed to Musa (saying): "Throw your stick," and behold! It swallowed up straight away all the falsehood which they showed (117)Thus truth was confirmed, and all that they did was made of no effect (118)So they were defeated there and returned disgraced (119)And the sorcerers fell down prostrate (120)They said: "We believe in the Lord of all that exists (121)"The Lord of Musa and Harun. (122) Musa defeats the Magicians, Who believe in Him Allah states that at that tremendous moment, in which Allah differentiated between Truth and Falsehood, He sent a revelation to His servant and Messenger Musa, peace be upon him, ordering him to throw the stick that he held in his right hand, فَإِذَا هِيَ تَلْقَفُ (It swallowed straight away) and devoured, مَا يَأْفِكُونَ (all the falsehood which they showed.) the magic that they caused the illusion with, of magic with which they caused m

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

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، أَخَّرَ الصَّلاَةَ يَوْمًا، فَدَخَلَ عَلَيْهِ عُرْوَةُ بْنُ الزُّبَيْرِ، فَأَخْبَرَهُ أَنَّ الْمُغِيرَةَ بْنَ شُعْبَةَ أَخَّرَ الصَّلاَةَ يَوْمًا وَهْوَ بِالْعِرَاقِ، فَدَخَلَ عَلَيْهِ أَبُو مَسْعُودٍ الأَنْصَارِيُّ فَقَالَ مَا هَذَا يَا مُغِيرَةُ أَلَيْسَ قَدْ عَلِمْتَ أَنَّ جِبْرِيلَ نَزَلَ فَصَلَّى، فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ صَلَّى فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ صَلَّى فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ صَلَّى فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ صَلَّى فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ قَالَ ‏ "‏ بِهَذَا أُمِرْتُ ‏"‏‏.‏ فَقَالَ عُمَرُ لِعُرْوَةَ اعْلَمْ مَا تُحَدِّثُ أَوَإِنَّ جِبْرِيلَ هُوَ أَقَامَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم وَقْتَ الصَّلاَةِ‏.‏ قَالَ عُرْوَةُ كَذَلِكَ كَانَ بَشِيرُ بْنُ أَبِي مَسْعُودٍ يُحَدِّثُ عَنْ أَبِيهِ‏.‏ قَالَ عُرْوَةُ وَلَقَدْ حَدَّثَتْنِي عَائِشَةُ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُصَلِّي الْعَصْرَ، وَالشَّمْسُ فِي حُجْرَتِهَا قَبْلَ أَنْ تَظْهَرَ‏.‏

Narrated Ibn Shihab:Once `Umar bin `Abdul `Aziz delayed the prayer and `Urwa bin Az-Zubair went to him and said, "Once in 'Iraq, Al-Mughira bin Shu`ba delayed his prayers and Abi Mas`ud Al-Ansari went to him and said, 'O Mughira! What is this? Don't you know that once Gabriel came and offered the prayer (Fajr prayer) and Allah's Messenger (ﷺ) prayed too, then he prayed again (Zuhr prayer) and so did Allah's Apostle and again he prayed (`Asr prayers and Allah's Messenger (ﷺ) did the same; again he prayed (Maghrib-prayer) and so did Allah's Messenger (ﷺ) and again prayed (`Isha prayer) and so did Allah's Apostle and (Gabriel) said, 'I was ordered to do so (to demonstrate the prayers prescribed to you)?'" `Umar (bin `Abdul `Aziz) said to `Urwa, "Be sure of what you Say. Did Gabriel lead Allah's Messenger (ﷺ) at the stated times of the prayers?" `Urwa replied, "Bashir bin Abi Mas`ud narrated like this on the authority of his father." `Urwa added, "Aisha told me that Allah's Messenger (ﷺ) used to pray `Asr prayer when the sunshine was still inside her residence (during the early time of `Asr)

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا عَبَّادٌ ـ هُوَ ابْنُ عَبَّادٍ ـ عَنْ أَبِي جَمْرَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَدِمَ وَفْدُ عَبْدِ الْقَيْسِ عَلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالُوا إِنَّا مِنْ هَذَا الْحَىِّ مِنْ رَبِيعَةَ، وَلَسْنَا نَصِلُ إِلَيْكَ إِلاَّ فِي الشَّهْرِ الْحَرَامِ، فَمُرْنَا بِشَىْءٍ نَأْخُذْهُ عَنْكَ، وَنَدْعُو إِلَيْهِ مَنْ وَرَاءَنَا‏.‏ فَقَالَ ‏ "‏ آمُرُكُمْ بِأَرْبَعٍ، وَأَنْهَاكُمْ عَنْ أَرْبَعٍ الإِيمَانِ بِاللَّهِ ـ ثُمَّ فَسَّرَهَا لَهُمْ شَهَادَةُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ، وَأَنِّي رَسُولُ اللَّهِ، وَإِقَامُ الصَّلاَةِ، وَإِيتَاءُ الزَّكَاةِ، وَأَنْ تُؤَدُّوا إِلَىَّ خُمُسَ مَا غَنِمْتُمْ، وَأَنْهَى عَنِ الدُّبَّاءِ وَالْحَنْتَمِ وَالْمُقَيَّرِ وَالنَّقِيرِ ‏"‏‏.‏

Narrated Ibn `Abbas:"Once a delegation of `Abdul Qais came to Allah's Messenger (ﷺ) and said, "We belong to such and such branch of the tribe of Rabi'ah and we can only come to you in the sacred months. Order us to do something good so that we may take it from you and also invite to it those whom we have left behind (at home)." So he said, "I order you to do four things and forbid you from four things: To believe in Allah" - and then he explained it to them "to testify that none has the right to be worshipped but Allah and that I am Allah's Messenger (ﷺ), to establish the prayers (at the stated times), to pay the Zakat (obligatory charity), to hand me the Khumus (fifth) if you acquire spoils of war. And I forbid from (using) Dubba, Hantam, Muqaiyyar, and Naqir (all these were utensils used for the preparation of alcoholic drinks)

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنِ ابْنِ شِهَابٍ، أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، أَخَّرَ الْعَصْرَ شَيْئًا فَقَالَ لَهُ عُرْوَةُ أَمَا إِنَّ جِبْرِيلَ عَلَيْهِ السَّلاَمُ قَدْ نَزَلَ فَصَلَّى أَمَامَ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏.‏ فَقَالَ عُمَرُ اعْلَمْ مَا تَقُولُ يَا عُرْوَةُ ‏.‏ فَقَالَ سَمِعْتُ بَشِيرَ بْنَ أَبِي مَسْعُودٍ يَقُولُ سَمِعْتُ أَبَا مَسْعُودٍ يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ نَزَلَ جِبْرِيلُ فَأَمَّنِي فَصَلَّيْتُ مَعَهُ ثُمَّ صَلَّيْتُ مَعَهُ ثُمَّ صَلَّيْتُ مَعَهُ ثُمَّ صَلَّيْتُ مَعَهُ ثُمَّ صَلَّيْتُ مَعَهُ ‏"‏ ‏.‏ يَحْسُبُ بِأَصَابِعِهِ خَمْسَ صَلَوَاتٍ ‏.‏

It was narrated from Ibn Shihab that 'Umar bin 'Abdul-'Aziz delayed the 'Asr prayer a little. 'Urwah said to him:"Jibril came down and led the Messenger of Allah (ﷺ) in prayer." 'Umar said: "Watch what you are saying, O 'Urwah!" He said: "I heard Bashir bin Abi Mas'ud say: 'I heard Abu Mas'ud say: "I heard the Messenger of Allah (ﷺ) say: 'Jibril came down and led me in prayer, and I prayed with him, then I prayed with him, then I prayed with him, then I prayed with him, then I prayed with him - and he counted off five prayers on his fingers

أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، قَالَ حَدَّثَنَا سَيَّارُ بْنُ سَلاَمَةَ، قَالَ سَمِعْتُ أَبِي يَسْأَلُ أَبَا بَرْزَةَ، عَنْ صَلاَةِ، رَسُولِ اللَّهِ صلى الله عليه وسلم قُلْتُ أَنْتَ سَمِعْتَهُ قَالَ كَمَا أَسْمَعُكَ السَّاعَةَ فَقَالَ سَمِعْتُ أَبِي يَسْأَلُ عَنْ صَلاَةِ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ كَانَ لاَ يُبَالِي بَعْضَ تَأْخِيرِهَا - يَعْنِي الْعِشَاءَ - إِلَى نِصْفِ اللَّيْلِ وَلاَ يُحِبُّ النَّوْمَ قَبْلَهَا وَلاَ الْحَدِيثَ بَعْدَهَا ‏.‏ قَالَ شُعْبَةُ ثُمَّ لَقِيتُهُ بَعْدُ فَسَأَلْتُهُ قَالَ كَانَ يُصَلِّي الظُّهْرَ حِينَ تَزُولُ الشَّمْسُ وَالْعَصْرَ يَذْهَبُ الرَّجُلُ إِلَى أَقْصَى الْمَدِينَةِ وَالشَّمْسُ حَيَّةٌ وَالْمَغْرِبَ لاَ أَدْرِي أَىَّ حِينٍ ذَكَرَ ثُمَّ لَقِيتُهُ بَعْدُ فَسَأَلْتُهُ فَقَالَ وَكَانَ يُصَلِّي الصُّبْحَ فَيَنْصَرِفُ الرَّجُلُ فَيَنْظُرُ إِلَى وَجْهِ جَلِيسِهِ الَّذِي يَعْرِفُهُ فَيَعْرِفُهُ ‏.‏ قَالَ وَكَانَ يَقْرَأُ فِيهَا بِالسِّتِّينَ إِلَى الْمِائَةِ ‏.‏

Shu'bah said:"Sayyar bin Salamah, narrated to us, he said: 'I heard my father ask Abu Barzah about the prayer of the Messenger of Allah (ﷺ).' I said: 'Did you really hear him?' He said: 'As I can hear you now.' He said: 'I heard my father ask about the prayer of the Messenger of Allah (ﷺ).' He said: 'He would not mind if he delayed it - meaning 'Isha' until midnight, and he did not like to sleep before it or speak after it.'" Shu'bah said: "Then I met him later on and asked him. He said: 'He used to pray Zauhr when the sun had passed its zenith, and (he would pray) 'Asr and a man could walk to the farthest point in Al-Madinah and the sun would still be clear and hot. And Maghrib, I do not know the time he mentioned.' After that I met him and asked him, and he said: 'He used to pray Fajr then after the prayer a man could regarding it, sitting next to him, look at the face of someone he knew and he could recognize it.' He said: 'And he used to recite in it between sixty and one hundred (verses)

وعبادته التي هو مشغول بها لا ينتقل إلى غيرها ولا يفتر عنها لا يستكبرون عن عبادته ولا يستحسرون يسبحون الليل والنهار لا يفترون ومفتاح مزيد الدرجات هي الصلوات

وينبغي أن لا ينفصل من طرف عرفة إلا بعد الغروب ليجمع في عرفة بين الليل والنهار وإن أمكنه الوقوف يوم الثامن ساعة عند إمكان الغلط في الهلال فهو الحزم وبه الأمن من الفوات

الباب الأول في فضيلة الأوراد وترتيبها في الليل والنهار

يشير إلى أنه غير متطلع إلى الأوقات بل هو مع الذي يقدر الليل والنهار

فهذا سؤال جاهل ظالم ضال مفرط في الجهل والظلم والضلال لأن خلق الأضداد والمتقابلات هو من كمال الربوبية كالليل والنهار والحر والبرد واللذة والألم والخير والشر والنعيم والجحيم

خلفة لمن أراد أن يذكر أو أراد شكورا} [الفرقان: 62]، أي يخلف أحدهما الآخر ليتدارك في أحدهما ما فات في الآخر. ### $ 2 - بيان عدد أوراد الليل والنهار وترتيبها

Diagnosis of circadian rhythm sleep disorders.: Insomnia and excessive sleepiness are common in the investigation of sleep-disordered breathing. Circadian rhythm sleep disorders are perhaps the most often overlooked conditions in the differential diagnosis of these symptoms. Circadian rhythm sleep disorders manifest as misalignment between the sleep period and the physical/social 24-h environmental cycle. The two most prevalent circadian rhythm sleep disorders are delayed sleep phase (common in adolescents) and advanced sleep phase (common in

Intrinsic circadian period of sighted patients with circadian rhythm sleep disorder, free-running type.: Background: Circadian rhythm sleep disorder, free-running type (FRT), is an intractable sleep disorder in which sleep and wake times progressively delay each day even in normal living environments. This disorder severely affects the social functioning of patients because of periodic nighttime insomnia, excessive daytime sleepiness, and a high rate of comorbid psychiatric disorders. Although abnormal regulation of the biological clock is suspected, the pathophysiology of FRT has yet to be elucida

Identification of a Preliminary Plasma Metabolome-based Biomarker for Circadian Phase in Humans.: Measuring individual circadian phase is important to diagnose and treat circadian rhythm sleep-wake disorders and circadian misalignment, inform chronotherapy, and advance circadian science. Initial findings using blood transcriptomics to predict the circadian phase marker dim-light melatonin onset (DLMO) show promise. Alternatively, there are limited attempts using metabolomics to predict DLMO and no known omics-based biomarkers predict dim-light melatonin offset (DLMOff). We analyzed the human

Home dim light melatonin onsets with measures of compliance in delayed sleep phase disorder.: The dim light melatonin onset (DLMO) assists with the diagnosis and treatment of circadian rhythm sleep disorders. Home DLMOs are attractive for cost savings and convenience, but can be confounded by home lighting and sample timing errors. We developed a home saliva collection kit with objective measures of light exposure and sample timing. We report on our first test of the kit in a clinical population. Thirty-two participants with delayed sleep phase disorder (DSPD; 17 women, aged 18-52 years)

A randomized controlled trial with bright light and melatonin for the treatment of delayed sleep phase disorder: effects on subjective and objective sleepiness and cognitive function.: Delayed sleep phase disorder (DSPD) is a circadian rhythm sleep disorder. Patients with DSPD have problems initiating sleep if they go to bed at a conventional time, and they often have problems waking at desired times. If they rise early in the morning, they usually experience severe sleepiness during morning hours. In the present study, we investigated the short- and long-term effects on measures of subjective and objective sleepiness and cognitive function of bright light and melatonin treatm

Light-induced changes of the circadian clock of humans: increasing duration is more effective than increasing light intensity.: Study objectives: To evaluate the effect of increasing the intensity and/or duration of exposure on light-induced changes in the timing of the circadian clock of humans. Design: Multifactorial randomized controlled trial, between and within subject design Setting: General Clinical Research Center (GCRC) of an academic medical center Participants: 56 healthy young subjects (20-40 years of age) Interventions: Research subjects were admitted for 2 independent stays of 4 nights/3 days for treatment

Metabolic consequences of stress during childhood and adolescence.

Stress, that is, the state of threatened or perceived as threatened homeostasis, is associated with activation of the stress system, mainly comprised by the hypothalamic-pituitary-adrenal axis and the arousal/sympathetic nervous systems. The stress system normally functions in a circadian manner and interacts with other systems to regulate a variety of behavioral, endocrine, metabolic, immune, and cardiovascular functions. However, the experience of acute intense physical or emotional stress, as well as of chronic stress, may lead to the development of or may exacerbate several psychologic and somatic conditions, including anxiety disorders, depression, obesity, and the metabolic syndrome. In chronically stressed individuals, both behavioral and neuroendocrine mechanisms promote obesity and metabolic abnormalities: unhealthy lifestyles in conjunction with dysregulation of the stress syst…

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Age-related changes in the cognitive function of sleep.

Healthy aging is characterized by a diminished quality of sleep with decreased sleep duration and increased time awake after sleep onset. Older adults awaken more frequently and tend to awaken less from rapid eye movement (REM) sleep and more from non-REM (nREM) sleep than young adults. Sleep architecture also begins changing in middle age leading to a dramatic decrease in the deepest stage of nREM-slow wave sleep (SWS)-as aging progresses. Other less marked nREM changes include reduced numbers of sleep spindles and K-complexes. In contrast, the amount of REM diminishes only slightly. Both circadian and homeostatic sleep-regulatory processes are affected by aging. Circadian rhythms of temperature, melatonin, and cortisol are phase advanced and their amplitude diminished. An increased number of nocturnal awakenings and diminished daytime sleepiness suggest diminished homeostatic sleep pre…

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Sleep and circadian functioning: critical mechanisms in the mood disorders?

Evidence for the importance of sleep in the mood disorders has mushroomed over the past decade. Among adolescents and adults with a mood disorder, sleep disturbance is a risk factor for episodes, can contribute to relapse, has an adverse impact on emotion regulation, is critical for cognitive functioning, compromises health, and may contribute to substance use comorbidity and suicidality. This evidence has triggered a shift away from viewing sleep disturbance as an epiphenomenon, toward viewing sleep disturbance as an important but under-recognized mechanism in the multifactorial cause and maintenance of the mood disorders. Because the biology underpinning the sleep and circadian system is an open system, readily influenced by inputs from the environment, sleep in the mood disorders represents a unique and exciting domain for interdisciplinary research across behavioral, social, cognitiv…

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Circadian rhythms and sleep in bipolar disorder.

Objective: Biological rhythm pathways are highlighted in a number of etiological models of bipolar disorder, and the management of circadian instability appears in consensus treatment guidelines. There are, however, significant conceptual and empirical limitations on our understanding of a hypothesised link between circadian, sleep, and emotion regulation processes in bipolar disorder. The aim of this article is to articulate the limits of scientific knowledge in relation to this hypothesis. Methods: A critical evaluation of various literatures was undertaken. The basic science of circadian and sleep processes, their involvement in normal emotion regulation, and the types of evidence suggesting circadian/sleep involvement in bipolar disorder are reviewed. Results: Multiple lines of evidence suggest that circadian and sleep-wake processes are causally involved in bipolar disorder. These p…

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The chronobiology, etiology and pathophysiology of obesity.

The effect of CD on human health is an emerging issue. Many records link CD with diseases such as cancer, cardiovascular, cognitive impairment and obesity, all of them conducive to premature aging. The amount of sleep has declined by 1.5 h over the past century, accompanied by an important increase in obesity. Shift work, sleep deprivation and exposure to bright light at night increase the prevalence of adiposity. Animal models have shown that mice with Clock gene disruption are prone to developing obesity and MetS. This review summarizes the latest developments with regard to chronobiology and obesity, considering (1) how molecular clocks coordinate metabolism and the specific role of the adipocyte; (2) CD and its causes and pathological consequences; (3) the epidemiological evidence of obesity as a chronobiological illness; and (4) theories of circadian disruption and obesity. Energy i…

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Sleep disorders in aging and dementia.

This paper reviews the characteristics of sleep disorders found in people at a greater risk of dementia: the elderly adult, patients with mild cognitive impairment (MCI) and those with neurodegenerative diseases. The frequency of sleep architecture modifications and circadian rhythm sleep disturbances increases with age. Although around 40% of older adults complain of poor sleep, true sleep disorders are far less prevalent in healthy older adults and are frequently associated with comorbidities. The sleep disorders observed in Alzheimer's disease (AD) patients are often similar to (but more intense than) those found in non-demented elderly people. Poor sleep results in an increased risk of significant morbidities and even mortality in demented patients and constitutes a major source of stress for caregivers. The prevalence of primary sleep disorders such as rapid eye movement (REM) sleep…

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Interactions of the circadian CLOCK system and the HPA axis.

Organisms have developed concurrent behavioral and physiological adaptations to the strong influence of day/night cycles, as well as to unforeseen, random stress stimuli. These circadian and stress-related responses are achieved by two highly conserved and interrelated regulatory networks, the circadian CLOCK and stress systems, which respectively consist of oscillating molecular pacemakers, the Clock/Bmal1 transcription factors, and the hypothalamic-pituitary-adrenal (HPA) axis and its end-effector, the glucocorticoid receptor. These systems communicate with one another at different signaling levels and dysregulation of either system can lead to development of pathologic conditions. In this review, we summarize the mutual physiologic interactions between the circadian CLOCK system and the HPA axis, and discuss their clinical implications.

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Jet lag and other sleep disorders relevant to the traveler.

Sleep and wakefulness are governed by homeostatic and circadian regulatory processes, and perturbations therein are primarily responsible for the sleep disturbances associated with travel. Misalignment between endogenous rhythms and the light/dark cycle can result in circadian rhythm sleep disorders, including jet lag. This condition will be the primary focus of this review, with an emphasis on predisposing factors, preventative options, and treatment strategies.

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Behavioural aspects of children's sleep.

There is good empirical evidence that behavioural factors play a role in the onset/maintenance of many childhood sleeplessness problems and that behaviour therapy can be used as an effective form of management. There is a smaller, but growing, literature supporting the idea that behavioural interventions may also play a significant role in the management of other types of sleep disorder (eg, rhythmic movement disorders, arousal disorders, nightmares and circadian rhythm sleep disorders), and this is an area ripe with research possibilities. This review outlines the nature of behavioural aspects of children's sleep and how these might be addressed by behaviour therapy. Clinical considerations concerned with the use of behavioural therapy are also highlighted (eg, the role of behaviour therapy as an adjunct to other treatments, its use with special populations, and how it might be delivere…

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Lab and field experiments: are they the same animal?

To advance our understanding of biological processes we often plan our experiments based on published data. This can be confusing though, as data from experiments performed in a laboratory environment are sometimes different from, or completely opposite to, findings from similar experiments performed in the "real world". In this mini-review, we discuss instances where results from laboratory experiments differ as a result of laboratory housing conditions, and where they differ from results gathered in the field environment. Experiments involving endocrinology and behavior appear to be particularly susceptible to influence from the environment in which they are performed. As such, we have attempted to promote discussion of the influence of housing environment on the reproductive axis, circadian biology and behavior, immune function, stress biology, neuroplasticity and photoperiodism. For …

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Human responses to the geophysical daily, annual and lunar cycles.

Collectively the daily, seasonal, lunar and tidal geophysical cycles regulate much of the temporal biology of life on Earth. The increasing isolation of human societies from these geophysical cycles, as a result of improved living conditions, high-quality nutrition and 24/7 working practices, have led many to believe that human biology functions independently of them. Yet recent studies have highlighted the dominant role that our circadian clock plays in the organisation of 24 hour patterns of behaviour and physiology. Preferred wake and sleep times are to a large extent driven by an endogenous temporal program that uses sunlight as an entraining cue. The alarm clock can drive human activity rhythms but has little direct effect on our endogenous 24 hour physiology. In many situations, our biology and our society appear to be in serious opposition, and the damaging consequences to our hea…

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The neuroendocrinology of stress: a never ending story.

Evolutionary success depends on our ability to adapt to changing circumstances. The neuroendocrine response to stress is an excellent example of a plastic system that responds to threats to homeostasis and alters its output to meet current and expected future demands. At the level of the hypothalamus, the corticotroph secretagogues corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) respond rapidly to an acute stressor but, following chronic stress, they adapt with a reduction of CRH but a major increase in AVP. The release of CRH and AVP activates pro-opiomelanocortin in anterior pituitary corticotroph cells and the release of adrenocorticotrophic hormone into peripheral blood from where it targets receptors in the adrenal cortex to release glucocorticoid hormones. These hormones (i.e. corticosterone in the rat and cortisol in man) are released in a pulsatile ultradian…

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Adaptive responses of the maternal hypothalamic-pituitary-adrenal axis during pregnancy and lactation.

Over the past 40 years, it has been recognised that the maternal hypothalamic-pituitary-adrenal (HPA) axis undergoes adaptations through pregnancy and lactation that might contribute to avoidance of adverse effects of stress on the mother and offspring. The extent of the global adaptations in the HPA axis has been revealed and the underlying mechanisms investigated within the last 20 years. Both basal, including the circadian rhythm, and stress-induced adrenocorticotrophic hormone and glucocorticoid secretory patterns are altered. Throughout most of pregnancy, and in lactation, these changes predominantly reflect reduced drive by the corticotropin-releasing factor (CRF) neurones in the parvocellular paraventricular nucleus (pPVN). An accompanying profound attenuation of HPA axis responses to a wide variety of psychological and physical stressors emerges after mid-pregnancy and persists u…

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"Speed" warps time: methamphetamine's interactive roles in drug abuse, habit formation, and the biological clocks of circadian and interval timing.

The indirect dopamine (DA) agonist methamphetamine (MAP) is evaluated in terms of its impact on the speed of temporal processing across multiple time scales involving both interval and circadian timing. Behavioral and neuropharmacological aspects of drug abuse, habit formation, neurotoxicity, and the potential links between interval and circadian timing are reviewed. The view that emerges is one in which the full spectrum of MAP-induced effects on timing and time perception is both complex and dynamic in as much as it involves DA-glutamate interactions and gene expression within cortico-striatal circuitry spanning oscillation periods ranging from milliseconds to multiple hours. The conclusion is that the psychostimulant properties of MAP are very much embedded within the context of temporal prediction and the anticipation of reward.

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From space to Earth: advances in human physiology from 20 years of bed rest studies (1986-2006).

Bed rest studies of the past 20 years are reviewed. Head-down bed rest (HDBR) has proved its usefulness as a reliable simulation model for the most physiological effects of spaceflight. As well as continuing to search for better understanding of the physiological changes induced, these studies focused mostly on identifying effective countermeasures with encouraging but limited success. HDBR is characterised by immobilization, inactivity, confinement and elimination of Gz gravitational stimuli, such as posture change and direction, which affect body sensors and responses. These induce upward fluid shift, unloading the body's upright weight, absence of work against gravity, reduced energy requirements and reduction in overall sensory stimulation. The upward fluid shift by acting on central volume receptors induces a 10-15% reduction in plasma volume which leads to a now well-documented set…

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Sleep and sleep disturbances: biological basis and clinical implications.

Sleep is a neurochemical process involving sleep promoting and arousal centers in the brain. Sleep performs an essential restorative function and facilitates memory consolidation in humans. The remarkably standardized bouts of consolidated sleep at night and daytime wakefulness reflect an interaction between the homeostatic sleep need that is manifested by increase in sleep propensity after sleep deprivation and decrease during sleep and the circadian pacemaker. Melatonin, the hormone produced nocturnally by the pineal gland, serves as a time cue and sleep-anticipating signal. A close interaction exists between the sleep-wake, melatonin, core temperature, blood pressure, immune and hormonal rhythms leading to optimization of the internal temporal order. With age the robustness of the circadian system decreases and the prevalence of sleep disorders, particularly insomnia, increases. Devia…

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Circadian rhythms in the CNS and peripheral clock disorders: human sleep disorders and clock genes.

Genetic analyses of circadian rhythm sleep disorders (CRSD), such as familial advanced sleep phase syndrome (ASPS) and delayed sleep phase syndrome (DSPS), and morningness-eveningness revealed the relationship between variations in clock genes and diurnal change in human behaviors. Variations such as T3111C in the Clock gene are reportedly associated with morningness-eveningness. Two of the pedigrees of familial ASPS (FASPS) are caused by mutations in clock genes: the S662G mutation in the Per2 gene or the T44A mutation in the casein kinase 1 delta (CK1delta) gene, although these mutations are not found in other pedigrees of FASPS. As for DSPS, a missense variation in the Per3 gene is identified as a risk factor, while the one in the CK1epsilon gene is thought to be protective. These findings suggest that further, as yet unidentified, gene variations are involved in human circadian activ…

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Sleep and circadian rhythms in children and adolescents with bipolar disorder.

The aim of this paper is to highlight the importance of the sleep-wake cycle in children and adolescents with bipolar disorder. After presenting an overview of the measurement and function of human sleep, we describe changes in sleep and circadian functioning across the life cycle. We then review evidence that, in adults, sleep and/or circadian rhythms are of considerable influence in the multifactorial causal chain implicated in relapse in bipolar disorder, discussing relevant mechanisms. The latter include abnormalities in the amount and timing of sleep, the role of social zeitgebers, and the importance of sleep in regulating emotional responses and mood. We next present preliminary data indicating considerable sleep disturbance among children and adolescents with bipolar disorder. Given the considerable sleep disturbance evident among children and adolescents with bipolar disorder alo…

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Light and the human circadian clock.

The circadian clock can only reliably fulfil its function if it is stably entrained. Most clocks use the light-dark cycle as environmental signal (zeitgeber) for this active synchronisation. How we think about clock function and entrainment has been strongly influenced by the early concepts of the field's pioneers, and the astonishing finding that circadian rhythms continue a self-sustained oscillation in constant conditions has become central to our understanding of entrainment. Here, we argue that we have to rethink these initial circadian dogmas to fully understand the circadian programme and how it entrains. Light is also the prominent zeitgeber for the human clock, as has been shown experimentally in the laboratory and in large-scale epidemiological studies in real life, and we hypothesise that social zeitgebers act through light entrainment via behavioural feedback loops (zeitnehme…

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Observed Relationship Behaviors and Sleep in Military Veterans and Their Partners.

Background: Emerging research has begun to examine associations between relationship functioning and sleep. However, these studies have largely relied on self-reported evaluations of relationships and/or of sleep, which may be vulnerable to bias. Purpose: The purpose of the study was to examine associations between relationship functioning and sleep in military couples. This is the first research to examine associations between observed relationship behaviors and subjective and polysomnographically measured sleep in a sample at-risk for both sleep and relationship problems. Methods: The sample included 35 military veterans and their spouses/partners. Marital functioning was coded from a videotaped conflict interaction. Analyses focused on behavioral codes of hostility and relationship-enhancing attributions. Sleep was assessed via self-report and in-home polysomnography. Results: Greater…

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Hippocampal-Prefrontal Reactivation during Learning Is Stronger in Awake Compared with Sleep States.

Hippocampal sharp-wave ripple (SWR) events occur during both behavior (awake SWRs) and slow-wave sleep (sleep SWRs). Awake and sleep SWRs both contribute to spatial learning and memory, thought to be mediated by the coordinated reactivation of behavioral experiences in hippocampal-cortical circuits seen during SWRs. Current hypotheses suggest that reactivation contributes to memory consolidation processes, but whether awake and sleep reactivation are suited to play similar or different roles remains unclear. Here we addressed that issue by examining the structure of hippocampal (area CA1) and prefrontal (PFC) activity recorded across behavior and sleep stages in male rats learning a spatial alternation task. We found a striking state difference: prefrontal modulation during awake and sleep SWRs was surprisingly distinct, with differing patterns of excitation and inhibition. CA1-PFC synch…

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Sleep selectively enhances memory expected to be of future relevance.

The brain encodes huge amounts of information, but only a small fraction is stored for a longer time. There is now compelling evidence that the long-term storage of memories preferentially occurs during sleep. However, the factors mediating the selectivity of sleep-associated memory consolidation are poorly understood. Here, we show that the mere expectancy that a memory will be used in a future test determines whether or not sleep significantly benefits consolidation of this memory. Human subjects learned declarative memories (word paired associates) before retention periods of sleep or wakefulness. Postlearning sleep compared with wakefulness produced a strong improvement at delayed retrieval only if the subjects had been informed about the retrieval test after the learning period. If they had not been informed, retrieval after retention sleep did not differ from that after the wake re…

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Elevated sleep spindle density after learning or after retrieval in rats.

Non-rapid eye movement sleep has been strongly implicated in consolidation of both declarative and procedural memory in humans. Elevated sleep-spindle density in slow-wave sleep after learning has been shown recently in humans. It has been proposed that sleep spindles, 12-15 Hz oscillations superimposed on slow waves (<1 Hz), in concert with high-frequency hippocampal sharp waves/ripples, promote neural plasticity underlying remote memory formation. The present study reports the first indication of learning-associated increase in spindle density in the rat, providing an animal model to study the role of brain oscillations in memory consolidation during sleep. An odor-reward association task, analogous in many respects to human paired-associate learning, is rapidly learned and leads to robust memory in rats. Rats learned the task over 10 massed trials within a single session, and EEG was …

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The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023.

Progress in the field of insomnia since 2017 necessitated this update of the European Insomnia Guideline. Recommendations for the diagnostic procedure for insomnia and its comorbidities are: clinical interview (encompassing sleep and medical history); the use of sleep questionnaires and diaries (and physical examination and additional measures where indicated) (A). Actigraphy is not recommended for the routine evaluation of insomnia (C), but may be useful for differential-diagnostic purposes (A). Polysomnography should be used to evaluate other sleep disorders if suspected (i.e. periodic limb movement disorder, sleep-related breathing disorders, etc.), treatment-resistant insomnia (A) and for other indications (B). Cognitive-behavioural therapy for insomnia is recommended as the first-line treatment for chronic insomnia in adults of any age (including patients with comorbidities), either…

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Aligning work and circadian time in shift workers improves sleep and reduces circadian disruption.

Sleep loss and circadian disruption-a state of misalignment between physiological functions and imposed sleep/wake behavior-supposedly play central roles in the etiology of shift work-related pathologies [1-4]. Circadian entrainment is, however, highly individual [5], resulting in different chronotypes [6, 7]. Chronotype in turn modulates the effects of working times: compared to late chronotypes, earlier ones sleep worse and shorter and show higher levels of circadian misalignment during night shifts, while late types experience more sleep and circadian disruption than early types when working morning shifts [8]. To promote sleep and reduce the mismatch between circadian and working time, we implemented a chronotype-adjusted (CTA) shift schedule in a factory. We abolished the most strenuous shifts for extreme chronotypes (i.e., mornings for late chronotypes, nights for early ones) and e…

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