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Nidra ks

  2. 2. GOVERNMENT AYURVEDA COLLEGE, KANNUR - PARIYARAM – 670502. CERTIFICATE This is to certify that the compilation entitled ‘Concept of Nidra’ is therecord of bona fide work done by Dr. Anjali Sivaram, under the direct supervisionand guidance of me, in the Dept. of Kriyasareera, Govt. Ayurveda College,Kannur. I strongly recommend and forward the same for being submitted forevaluation. Dr. Anny Yohannan. MD (Ay), Professor & H.O.D.,Place: Dept. of Kriyasareera, Govt.Ayurveda College,Date: Pariyaram, Kannur. 2
  3. 3. Contents Page no. 1. Introduction 1 2. What is nidra? 2 3. Nidra- when and why? 3 4. Effects of nidra 4 5. The duration and time of nidra 5 6. Types of nidra 6 7. Similar conditions like nidra 8 8. Sayana vidhi 9 9. Unhealthy nidra habits 10 10. Nidra- one of the vegaas 14 11. Nidraanaasa 15 12. Atinidraa 16 13. Ayurvedic glossary of nidra 16 14. Sleep- the modern aspect of nidra 18 15. Sleep rhythm 18 16. Sleep requirement 19 17. The sleep cycle 20 18. Stages of sleep 20 19. Physiological changes during sleep 24 20. Theories of sleep 27 21. Brain areas of sleep 28 22. Factors affecting sleep 30 23. Sleep disorders 31 24. Conclusion 33 3
  4. 4. BIBLIOGRAPHY 1. Ashtanga hrdayam, Vagbhata with Sarvanga sandara vyakhya by Arunadatta, Choukhamba Orientalia, 1989 2. Ashtanga samgraham, Vrddha Vagbhata with Prakaasika vyakhya by Vaodyabhushanam. K. Raghavan Thirumulpad, 1st edition, 1982 3. Bhaavaprakasa, Bhaava mishra 4. Charaka Samhita, Ayurveda deepika vyakhya by Chakrapaanidatta, edited by Vd. Yadavji Trikumji, Munshiram publishers, 5th edition,1992 5. Concept of mind, by a group of authors, Dept. of Samhitas& Siddhantas, V.P.S.V Ayurveda college, kottakkal. 6. Sabdakalpadrumam 7. Susruta Samhita,Nibandha Samgraha vyakhya by Dalhana edited by Vd. Yadavji Trikumji, Krishnadas Academy, Choukhaba Orientalia, !989 8. Svastavrttam, Kerala government Ayurveda publication-18Modern texts 1. Concise Medical Physioloigy- Sujit.K.Chaudhuri, 5th edition 2. Human physiology, C.C.Chatterjee, 11th edition 3. Oxford text book of psychiatry, Michael Gelder, Dennis Gath, Richard Mayou, ELBS, 2nd edition 4. Principles and application psychology, Stephen Worchel, Wayne Shebilske, Prentice Hall, 5th edition 5. Principles of anatomy and physiology, Tortora, Grabowski, 8th edition 6. Review of medical physiology, William.F.Ganong,21st edition 7. Text book of medical physiology, Guyton&Hall, 9th edition 4
  5. 5. Introduction Why Charakacharya mentioned the trayopastmbhas as the first one of theseven trios? It is only because of the utmost importance of this trio in themaintenance of health. Ayurveda just can not forget this group of factorsbecause a proper management of these factors is truly essential for the healthand any mismanagement can result in serious unhealthy state of body and/ormind. The etiology of many of the diseases of this eon suggests the same. The trayopastmbhas are the subsidiary pillars, which support the bodythrough out the life span, by providing the qualities like bala, varna, upachayaetc. They are considered as subsidiary or secondary as the principal pillars oflife are the three doshas. But their importance in the normal functioning of thebody can not be over looked. The trayopastmbhas are aahara, nidra and brahmacharya. Each one ofthese deserves due importance because these factors are concerned with thebasic needs of living system and over indulgence or total abstinence of any ofthese may be harmful to life. Hence one should apply rational thought as well asscientific knowledge to while designing one’s own lifestyle. The aahara is mainly concerned with the energy production andmaintenance of living tissues. The nidra is the one which provide completerelaxation to the body and mind and there by it restore the potentials of theindividual. The brahmacharya is concerned with disciplined mode of sexual lifeand reproduction.What is nidra? 5
  6. 6. The term ‘nidra’ is derived as “nindyate iti nidra” (Sabdakalpadrumam) According to darsanas, there are four avasthas or states of mind andatma. They are v Jaagradavastha v Svapnavastha v Sushuptiavastha v Tureeyavastha Jaagradavastha- In this phase, the person is able to perceive subject via panchendriyas Svapnavastha- This is the phase of sleep in which the person experiences some feelings depending upon what he has done or perceived during the jaagradavastha. Sushuptiavastha- This also is a phase of sleep but nothing is experienced by the person. Only the life sustaining vital functions (like respiration, circulation etc) happen. Tureeyavastha- This is experienced only by yogis. Due to aadhikya in satva guna, the person has full control over his nidra and there is no effect of tamoguna on this phase.In nidra, both the Svapnavastha and Sushuptiavastha are included. According to yoga sastra, the nidra is a type of chittavrtti and it is theaasraya to the cause of abhaava of manovishaya. 6
  7. 7. ‘Abhaava pratyayaalambanaavrtti nidra”In other words, nidra is that function of mind which blocks all the perception doneby the mind. During nidra the mind is subjected to the feeling from inside i.e.from the mind itself.Nidra-when and why? Charakacharya explains the nidra as “yadaa tu manasi klante karmaatmanah klamaanvitaah vishayebhyo nivartante tadaa svapiti maanavah” (C.Sutram 21/35)It is a special state of mind in which the mind is not associated with any type ofindriyas. This detachment from the bahya vishaya is resulted from the tirednessof body as well as mind.Kapha dosha and tamoguna are responsible for sleep. According to Susrutacharya, the nidra occurs when thechetanaasthaanam i.e. hrdaya is covered by tamoguna. “hrdayam chetanaasthaanamuktam susruta dehinaam tamo abhibhute tasmimstu nidraavisati dehinaam nidrahetustamah satvam bodhane heturuchyate svabhaavaeva vaa heturgareeyan parikeertyate” (S.sareeram)For vaagbhata, nidra is tamomoola and tamomayi “lokaadi sarga prabhavaa tamomoolaa tamomayee baahulyat tamaso ratrau nidra praayena jaayate 7
  8. 8. sleshmaavrteshu srotassu sramaaduparateshu cha indriyeshu sva karmabhyo nidraavisati dehinaam” (A.S.sootram 9) The night is tamo adhika, by its nature. This tamo aadhikya contributes tothe nidra as nidra itself is tamomoola and tamomayi. In addition when the mindbecomes tamo adhika and/or body becomes kaphaadhika (which is the bodilycounterpart of tamoguna) indriyas become inactive and nidra happens.Effects of nidra The physiological change during sleep is best manifested in the heart.The heart or hrdaya is compared with a lotus flower which blooms in the day timeand withers in the night time. Similarly the hrdaya droops when the personsleeps. The body achieves the proper relaxation and rest through the sleep.Thus nidra is as important as nutritious food for the maintenance of health.(Aatreya Samhita) Charakacharya opines that the sukha & duhkha, pushti & kaarsya, bala &abala, vrshata & kleebata, jnana & ajnana and the very presence and absence oflife depend on the management of sleep pattern. A well modulated sleep patternsurely brings delight and longevity to the person. (C.sootram21/36) Susrutacharya also has similar opinion. He says that the nidra bringsbala, varna, vrshyata to the person and the body of such persons may be well 8
  9. 9. built but not obese. The lifespan of such a person may extend up to hundredyears. Bhaavamisra opines that the nidra in the proper time providedhatusaamya, absence of tandra, pushti, varna, bala and utsaaha. In addition italso causes agnideepti. “nidraa tu sevitaa kaale dhatu saamyamatandritaam pushtim varnam balotsaaham vahnideepthi karoti hi” (B.P.poorvam5/3-5)The duration and time of nidra Susrutacharya says that the person should sleep for a moderate timeperiod only. “budhah svapnam mitam charet” This is so relevant because the nidra at an improper time and duration cannot produce any desirable effect but the effect of such nidra may be like theeffect of kaala raatri. (C. sootram21/37-38)Hence the effect of nidra strictly depends on the proper timing. (B.P.poorvam5/3) Why such restriction in the time and duration of nidra has been suggestedby acharyas? It is because the deprivation of sleep during night and sleeping inthe day time are equally disagreeable to health for, they alter the equilibrium ofdosha of body considerably.Still Susrutacharya advocates that one should follow the timing of sleep, to whichhe is accustomed, without any difference. If it is saatmya, the nidra at any timewon’t alter the doshavastha. 9
  10. 10. “nidra saatmeekrtaa yaistu ratrau cha yadi vaa divaa na tesham svapataam dosho jaagrataam vaapi jaayate” (S.sareeram4/41)Types of nidra According to Charakacharya as well as Vaagbhatacharya, there are 7types of nidra. But Susrutacharya opines that there are 6 types of nidra.7 types of nidra v Taamasa nidra: the nidra due to the increased tamo guna of the manas v Kaphaja nidra: the nidra due to the increased kapha dosha in the body v Manah sramabhava nidra: the nidra due to the exhaustion of manas or mind v Sareera sramabhava nidra: the nidra due to the exhaustion of sareera or body v Aagantukee nidra: the nidra which forecasts death v Vyaadhyanuvartinee nidra: the nidra which occurs due to some diseases v Praakrtika nidra: the natural form of nidra which happens in nights. “tamobhavaa sleshma samudbhavaa cha manassareera srama sambhavaa cha aagantukee vyaadhyanuvartinee ch 10
  11. 11. raatri svabhaava prabhavaa cha nidra” (C.sootram21/58)Among these 7 types of nidra the paakrtika nidra is the only desirable one. It isalso called ‘bhootdhaatri’ as it fosters the living things as their mother. TheTaamasa nidra is the worst as it is the root cause of each and every sin. Theremaining 5 reveal the unhealthy state only and they should be regarded asdiseases.6 types of nidra v Vaishnavi: it is the one which is included under the upastambha group. As it is so helpful to the maintenance of the healthy state of an individual (just like the lord Vishnu maintain the harmony of universe) it is called vaishnavi. v Taamasi: it is the form nidra which occurs due to excess tamas or kapha in the sanjnaavahasrotas. v Nidra in tamoguna persons: here the nidra comes irrespective of day and night. v Nidra in rajo guna persons: here the nidra can come at any time irrespective of day and night. But this may not happen always. v Nidra in satva guna persons: here the sleep comes only in midnight v Vaikaariki: it is the form of nidra resulted from some disease.Similar conditions like nidra 11
  12. 12. As per Susrutacharya, tandra is similar state like nidra but with increasedgaurava, jrmbha and klama. Nidra like conditions can be produced byabnormality of indriyas as well as increased tamas. Saarngadharacharya opines that nidra is produced by the action of tamasand kapha while moorchha is produced by tamas and pitta. Bhranti happens dueto the influence of rajas and pitta and tandra is produced by tamas and vaayu.Hence the conditions similar to nidra can be counted as follows: 1. Tandraa- is a condition characterised by reduced acuity of perception, yawning and tiredness. This condition is similar to intense urge for sleep. This may be correlated with stupor. This is caused by the increase of tamas,vaata and kapha. 2. Jrmbhaa- yawning 3. Klama- usually fatigue occurs after physical labour. A condition of tiredness without prior physical exertion is called klama. It may be roughly correlated with exhaustion. 4. Aalasyam- Laziness. It is the lack of interest to work. Technically it is the aptitude for rest and the aversion for work even when the person is having sufficient physical strength for doing work. 5. Glaani- is a state characterised by abnormal sweet taste in mouth, stupor, nausea, giddiness and anorexia 6. Gauravam- feeling of heaviness, as though wrapped in wet leather. 7. Moorcchaa- fainting caused by the increase of pitta and tamas. 8. Bhramaa- giddiness due to the increase of rajas, pitta and vaata. 12
  13. 13. (S. sareeram 4/49-56)Sayana vidhi The Vaagbhatacharya suggests that a person can go to bed for sleep aftertaking light but healthy supper. He should avoid all the distressing thoughts andthus clean the mind. Just before sleeping one should think about the almightyGod. He can use a pillow which is comfortable for him. The bed should becovered with clean bed linen and it should be wide and even and should becomfortable for the person. (A.S. sootram 3/118-120) The sayanavidhi formulated by Bhaavamisra also convey the idea aboutthe qualities and effect of different ‘sayya’ or bed as well as the place to sleep.He opines that sleeping on bed with good qualities is hrdya and vrshya. Itremoves the tiredness of body and mind and provides pushti, dhrti and soundsleep. Sleeping on cot is tridoshasamana. Sleeping on bed which is filled withfeather is kapha vaatahara. Sleeping on floor provides brmhana and vrshyataand reduces the pitta and rakta doshas. Sleeping on plank is vatala.“susayyaasayanam hrdyam pushtinidraadhrtipradamsramaanilaharam vrshyam vipareetamatonyadhatridosha samanee khatvaa toolee vaata kaphaapahaabhoosayyaa brmhanee vrshyata kaashtha pattee tu vaatalaabhoosayyaa vaatalaateeva rookshaa pittaasranaasinee” (B.Ppoorvam5/200-202) Sleeping in the moonlight is seeta and provides smraananda. It reducestrshna, daaha and pitta. Compared to this, sleeping in the avasyaya is of less 13
  14. 14. qualities because it may cause vaata kaphakopa. Sleeping in complete darknessmay frighten the individual because when gets up from sleep suddenly one cannot identify the place and direction due to extreme darkness. But it is pitta kaphaSamana and kaamavardhana. It creates klama.“jyotsnaa seetaa smaraanandapradaa trtpittadaahakrttatoheena gunah kuryaadavasyayo anilam kaphamtamo bhayaavaham moha dingmohajanakam bhavetpittahrt kaphahrt kaamavardhanam klamakrt cha tat” (B.P. poorvam 5/277-278)Unhealthy nidra habits There are two types of sleep habits which are described as totallyunhealthy in nature. They are ‘divaasvapna’ and ‘raatrijaagarana’Divaasvapana Night is the accepted time for nidra and sleeping in the day time is contraindicated as it may produce sleshma pitta kopa. “greeshma varjyeshu kaaleshu divaasvapnaat prakupyatah sleshmapitte, divaasvapnastasmaatteshu na sasyate” (C.sootram 21/44) There are some special occasions in which sleeping in day time isindicated. They can be categorized as follows: o In relation with rtu o In relation with diseases o In relation with activities 14
  15. 15. o In special category individualsIn relation with rtu: Divaasvapna is indicated in greeshma rtu to all the individuals. This isbecause, o Greeshma rtu comes under aadana kaala which characterised by rookshana svabhaava. This causes vaata vrddhi. Inorder to reduce this effect divaasvapna can be performed. o The duration of night is much reduced in greeshma rtu. In order to get the required sleep, one can sleep in the day time also. “greeshme tuaadana rookshanaam vardhamaane cha maarute raatrinam chaatisamkshepaat divaasvapnah prasasyate”(C.sootram21/43) “greeshme vaayuchayaadaanaraukshyalpa bhaavatah divaasvapna hito anyasmin kaphapittakaro hi sah” (A.S. sootram 7/56)In relation with diseases: That there are some diseases in which, divaasvapna is indicated toreduce the tiredness and other ill effects caused by these diseases. Theyinclude (C.sootram 21/39-40) o Trshna o Soola o Hikka o Jeernaatisaara o Svaasa 15
  16. 16. o Ajeerna o KshataIn relation with activities: Divaasvapna can be performed following the activities like, o Singing o Long lecture o Consumption of alcohol o Sexual intercourse o Sodhana therapy o Weight lifting o Walking long distances o Traveling in vehicles o Deprivation of sleep in night o Emotional outbursts Divaasvapna just before the intake of food is favorable as it improves the digestive capacity.In special category individuals: o Vrddha (old people) o Baala (children) o Abala (weak people) o Krsa (lean people) 16
  17. 17. o Those who are accustomed to the divaasvapnaHere, the divaasvapna brings about dhaatusaamya, bala, sleshmavrddhi,sthairya or stability of body parts and life.“sarva ete divaasvapnam severan saarvakaalikamdhaatusaamyam tathaa hyeshaam balam chaapyupajaayatesleshmaapushnaati chaangaani sthairyam bhavati chaayushah”(C.sootram21/42)Divaasvapna –contra indications. Divaasvapna is generally contra indicated in all rtus except greeshma as itmay cause sleshma pitta kopa. In addition, in the following categories also, thedivaasvapna is strictly contra indicated o Obese individuals o Those who take fatty substances daily o Kapha prakrti individuals o Those who suffer from kapharogas o Those who suffer from doosheevisha “medasvinah snehanityaah sleshmalaah sleshmaroginah doosheevishaartaascha divaa na sayeeran kadaachana”(C.sootram21/45)Yoga ratnaakarakaara opines that the sleeping after the intake of food is sounhealthy that it causes kopana of all the three doshas.The adverse effects of divaasvapna in totally contra indicated conditions: The performance of divaasvapna in totally contraindicated conditions mayproduce certain complications like haleemaka, sirassoola, staimitya,gaatragaurava, angamarda, agni maandya, hrllepa, sotha, arochaka, hrllasa, 17
  18. 18. peenasa, arddhavabhedaka, kotha, arumshika, pitaka, kandu, tandra, kaasa,galaroga, smrtibhramsa, buddhibhramsa, srotorodha, jvara, lack of ability ofindriyas, vishavegapravartana in vishaartas. (C.sootram 21/46-49)But sleeping in sitting posture is neither abhishyandi nor rookshana. “arookshanamanabhishyandi tvaseenaprachalaayitam”Raatrijaagaranam As stated elsewhere the night is the suitable time for sleep and it shouldbe used for sleeping. The deprivation of sleep in night time is extremelyrookshana and it causes vaatapitta vrddhi. But raatrijaagaranam is indicated inthose who suffer from kapha or medas or visha.Nidra- one of the vegaas Vegas are the natural urges which should not be controlled deliberately.Nidra is one among the 13 vegas. The dhaarana of nidraavega may causemoha,gaurava of sirah and akshi, aalasya, jrmbha and angamarda. Thetreatment that can be given to these symptoms is nothing but to allow theindividual to sleep. Gentle touch also can promote sleep. (A.H.sootram 4)Nidraanaasa Nidraa naasa is nothing but the inability to sleep in night. This may becaused by vaatadosha or pittadosha or due to manastaapa, sosha or abhighata. 18
  19. 19. “nidraanaaso anilaat pittat manstaapat kshayaadapi sambhavatyabhighaatat cha pratyaneekai prasaamyati” (S. sareeram4/42)The causes of nidraanaasa can be tabulated as follows: (C.sootram 21/55-57)Treatment processes Virechana, nasya, vamana, dhoomapaana, raktamokshana, atiyoga of atinidraa treatmentFeelings Bhaya, chintaa, krodhaCondition of manas Increased satva, reduced tamasExternal conditions Vyaayaama, upavaasa, asukhasayyaaOther factors Kaarya, kaala, vikaara, prakrti, vaatavrddhi Nidraanaasa my cause angamarda, sirogurutva, jrmbha, jaadya, glaani,bhrama, apakti, tandraa and other rogas caused by vaata dosha. “nidraanaasad angamarda sirogaurava jrmbhikaa jadya glani bhrama apkti tandraa rogaascha vaatajaah” (A.H.sootram7/64)Treatment for nidraanaasa: There are some effective guidelines to get sound sleeps. They include,the usage of the following processes and products like abhyanga (externalapplication of oil), utsaadanam, snaana, intake of graamya, anoopa or audakavariety of meat, saaliannam, milk , curd, fattyfooditems, alcoholic beverages, 19
  20. 20. relaxed mind, pleasant smell, pleasing sound, gentle touch, akshi tarpana,sirolepa, vadanalepa, goodbed bedlinen, appropriate time for sleep etc.“abhyangotsaadanam snaanam graamayaanoopaudakaarasaahsaalyannam sadadhiksheeram sneho madyam manah sukhammanaso anugunaa gandhaah sabdaah samvahanaani chachakshushostarpanam lepah siraso vadanasya chasvaasteernam sayanam vesma sukham kaalastathochitahaanayantyachiraannidraam pranashtaa yaa nimittatah” (C.sootram 21/52-54)Atinidraa Atinidraa is caused by increased kapha in the srotas which may lead togaatra gaurava. Gaatra gaurava causes aalasya which in turn results in nidra.This is not at all favourable for the body as well as mind.Prognosis of atinidraa Atinidraa if not exceeded 1 ½ days, is saadhya and beyond that it isasaadhya.Ayurvedic glossary of nidra (sleep) Aalasya - laziness Alpanidrataa - reduced sleep Anidrataa - insomnia Asvapnah - sleeplessness Atisvapnah - excessive sleep Bahusvapnah - excessive sleep 20
  21. 21. Jaagaranam - keeping awake Jrmbhaa - yawning Klama - exhaustion Mada - intoxication Mahaasvapnah - excessive sleep Moorcchaa - fainting Nidra - sleep Nidraabhaava - insomnia Nidraabhramsa - interrupted sleep Nidraahaani - lack of sleep Nidraanaasa - insomnia Nidraaviparyaya - day sleep and night awakening Nistandrataa - lack of tiredness in spite of not sleeping Prajaaagaranam - keeping awake Sayana - 1) sleep 2) lying down Svapna - 1) sleep 2) dream Svapnanityataa - excessive sleep Sannyaasa - coma Tandraa - stupor Unnidrataa - inability to sleep Vinidrataa - insomniaSLEEP-the modern aspect of nidra 21
  22. 22. Sleep is a physiological phase of ‘unawakening’ that exists between twophases of normal and routine awakening. It is a period of rest for the body andmind during which bodily functions are partially suspended and sensitivity to theexternal stimuli is diminished, but readily or easily regained.Clinical features of sleep: Usually a person sleeps about 8 hours in a 24 hours period. During sleep • The person appears to be cut off from the environment • The threshold for various sensory stimulations are substantially raised • Muscle tones fall and muscle relax • Blood pressure, heart rate and rectal temperature fall, respirations become slower but deeper.Some persons snore due to the fact that relaxed tongue in supine posture partlyobstructs the air passage.Sleep rhythm Animals and humans show one sleep period in 24 hours. Night,commonly being the period of rest, is used for sleep. But this considerably varieswith habit. (In night shift workers, day sleeping is the habit.) A term ‘sleep wake cycle’ is frequently used. In a 24 hour period, a man,sleeps about 7 hours and remains awake for the 17 hours. So the sleep wakecycle of the given person id 7/17 hours. Sleep wake cycle of a given person isreasonably fixed. If for any reason a person has to sleep less for one or twodays, he compensates the lost hours of sleep by oversleeping in the following 22
  23. 23. days. This is an example for the working of biological clock and this rhythm ofsleep is often termed as circadian rhythm.Sleep requirements During sleep the body gets repaired by itself and the brain processes theday’s events and help to sort them. Some sleep more and others sleep less, butboth may be normal. The range of deviation of sleeping hours in the normaladult population is 4 to 10 hours per day, although the infants and children sleepmore while the old people sleep less. A normal adult can withstand several days(up to 10 days) of sleep deprivation without showing any remarkably grosschanges. Category Sleep requirement New born babies 16- 20 hours Children 12-14 hours Adults 4-10 hours Old age About 5 hours Infants sleep for pretty shorter periods at a stretch. In a new born ingantthe duration of each sleep is only up to 60 minutes. Sleep alternates with statesof wakefulness. The state of wakefulness is also about one hour. When theinfant is one year old, the length of periods of sleep and wakefulness becomeslonger and extend up to 90 minutes. Later, day time sleep becomes lighter and 23
  24. 24. the child gets longer sleep at night. As the child grows older, he may require onlyone or two day time naps.The sleep cycle An individual sleep cycle lasts for about 1 ½ hours. Thus assuming asubject sleeps for about 8 hours in a night there will be some five such sleepcycles in the whole period. Each cycle of the sleep contains various stages ofsleep.Stages of sleep Normal sleep consists of two types: - non rapid eye movement sleep(NREM sleep) or slow wave sleep and rapid eye movement sleep (REM sleep).Because of the fact that eyeballs move and yet the sleep is deeper, the REMsleep is also called paradoxical sleep The physiological characteristics of thesephases are largely opposite. Both the phases have a complex multilevelstructure that ensures the development of active brain processes characteristic ofeach phase. In NREM sleep, tonic or stable changes in vegetative and motorindices occur. The muscular tension decreases, respiratory rate and cardiacrhythm become slow. In REM sleep, the EEG records rapid low amplitudeoscillations, similar to those in the initial stage of sleep or even wakefulness.Physical changes are also noted. Rapid eye movements, twitching of facialmuscles and extremities, disturbed breathing, changes in heart rate andhypertension are seen in REM sleep 24
  25. 25. The NREM or slow wave sleep consists of four stages, each of whichgradually merges into the next. Each stage has been identified by EEGrecordings. • Stage 1- This is a transition stage between wakefulness and sleep that normally lasts from 1 to 7 minutes. The person is relaxing with eyes closed and has fleeting thoughts. If awakened, the person will often say he has not been sleeping. Alpha waves diminish and theta waves appear on the EEG. • Stage 2- This is the first stage of true sleep, even though the person experiences only light sleep. It is a little harder to awaken the person. Fragments of dreams may be experienced, and the eyes may slowly roll from side to side. The EEG shows sleep spindles- sudden, short bursts of sharply pointed waves that occur at 12 to 14 Hz. • Stage 3- This is a period of moderately deep sleep. The person is very relaxed. Body temperature begins to fall and blood pressure decreases. It is difficult to awaken the person, and the EEG shows a mixture of sleep spindles and delta waves. This stage occurs about 20 minutes after falling asleep. • Stage 4- Deep sleep occurs. The person is very relaxed and responds slowly if awakened. When bed wetting and sleep walking occur, they do so during this stage. The EEG is dominated by delta waves. 25
  26. 26. In a typical 7 or 8 hours sleep period, a person goes from stage 1 to 4 ofNREM sleep. Then the person ascends to stage 3 and 2 and then to REMsleep within 50 to 90 minutes. The cycle normally repeats throughout thesleep period. In REM sleep the EEG readings are similar to those of stage 1 ofNREM sleep. It is during this sleep that most of the dreaming occurs. Theeyeballs move frequently, the muscles relax more and the intensity ofsleep is more. The eye ball movements are probably due to the fact thatthe subject follows the objects in the dream. Yet because of greatermuscle relaxation, the subject is unable to move. May be because of this,the subject feels a sense of paralysis, even though the situation in thedream demands physical movements. In men, erection of the penishappens during most REM intervals, even when the dream content is notsensual. Following REM sleep, the person descends again to stage 3 and4 of NREM sleep. Towards morning the REM sleep becomes longer andNREM sleep becomes shorter. The REM periods start out lasting from 5to 10 minutes and gradually lengthen until the final one lasts about 50minutes. Most sedatives significantly reduce REM sleep. If people are awakened during REM sleep they almost always saythey have been dreaming and they are able to recall their dreams in vividdetails. When people are awakened during stage 2 through stage 4 theyrarely claim to have been dreaming and they never remember manydetails. However, strong panic emotions with little dream imagery occur in 26
  27. 27. stage 3 and 4. These emotions are called night terrors or sleep terrors. They consist of labored breathing and paralysis and high anxiety. As a person ages, the average time spent sleeping decreases. In addition, the percentage of REM sleep decreases. As much as 50% of an infant’s sleep is REM as contrasted with 35% for 2 year olds and 25% for adults. The high percentage of REM sleep in infants and children is thought to be important for the maturation of the brain. Neuronal activity is high during REM sleep; brain oxygen use is higher during REM sleep than during intense mental or physical activity while awake.The sleep pattern of an individual changes significantly after a long period ofsleep deprivation. Scientists observed that the individual, after a period of sleepdeprivation of 264 hours, spent much more time in stage 4 on the first recoverynight, at the expense of stage 2. On the second recovery night, REM sleepincreased sharply at the expense of stage 2 through 4. The phenomenon ofincreased REM sleep after sleep deprivation is called REM rebound. The effects of sleep deprivation suggest that sleep repairs and restoresvarious systems. Prolonged deprivation leads to irritability, fatigue, poorconcentration, memory failure and reduced muscle co ordination. Some peopleare associated with behavioral abnormalities and mental illness. When the people are allowed to sleep except when thy enter stage 4 andREM sleep, they develop the same symptoms as if they had been deprived of alltheir sleep. Such experiments indicate that we need sleep especially stage 4 27
  28. 28. and REM to maintain normal functions. Selective deprivation of REM sleepalone suggests that it is especially important in solidifying memories fro skillslearned the day before. The skills are remembered less well by REM deprivedpeople than they are by people who sleep normally or by people who aredeprived of other stages of sleep.Physiological changes during sleep During sleep, somatic activity is greatly decreased. Threshold of manyreflexes is elevated and responsiveness is also lessened. Man cannotremember the events occurring during sleep. The metabolic rate being the least, all tissues and organs perform theleast work. The physiological changes can be tabulated as follows:Systems/somatic functions Changes during sleepCirculatory system Pulse rate, cardiac output, vasomotor tone and blood pressure reducedRespiratory system a) Respiration may be costal or periodic, specially in children b) Tidal volume, rate of respiration and, therefore, pulmonary ventilation-lowered. (Sometimes the rate may be unchanged or even high due to shallow breathing.Metabolic rate Reduced by 10-15% 28
  29. 29. Secretions a) Salivary and lacrimal reduced b) Gastric- unaltered or raised c) Sweat- raised d) hGH of pituitary- increasedUrine Volume reduced, reaction may be variable, specific gravity and phosphates- raisedMuscles Relaxed and the tone is minimumEyes a) Eye balls- roll up and out due to flaccid external ocular muscles may take up any position b) Eye lids- come closer, specially due to drooping of upper eyelid c) Pupils- contractedBlood Volume is increased due to dilution of plasmaNervous system a) Deep reflexes reduced b) Babinski- extensor c) Superficial reflexes unchanged d) Vasomotor reflexes- more brisk e) Light reflex- retained 29
  30. 30. In addition to this remarkable changes can be identified in theelectroencephalogram (EEG). The variation in EEG according to the changes inthe stages of sleep can be tabulated as follows:Stage of sleep EEG pattern Clinical signs0 Alpha rhythm when eyes are Awake closedI Alpha rhythm DozingII a) Spindles Unequivocal sleep b) Theta rhythmIII a) Delta rhythm Deep sleep b) Theta rhythmIV Delta rhythm Deep sleepREM Mixed frequency, but mostly low Considerable eyeball voltage, fast waves resembling movements, dreaming, awakened state with eyes open. night mares (In the dreams the subject is seeing something; may be because of this the EEG develops alpha block rhythm)N.B: When attention is focused on something, the alpha rhythm is replaced byfast, somewhat irregular low voltage activity. This phenomenon is called alphablock. 30
  31. 31. Theories of sleep There are several theories for explaining the cause of sleep, but none isquiet satisfactory. 1) Cerebral ischemia: Sleep is due to cortical ischemia. The drowsiness after food is due to splanchnic vasodilatation, fall of blood pressure and consequent cerebral ischemia. 2) Pavlov’s theory: Sleep is a special manifestation of conditioned inhibition. It is due to spread of an internal inhibitory process and is considered the concomitant sleep as a symptom of the cortical inhibition. 3) Biochemical aspects: Many chemical substances are considered to be able to induce sleep. They include acetylcholine, lactic acid, bromhormone, serotonin etc. But almost all of these hypotheses are not proved satisfactorily. 4) Kleitman’s theory: Due to reduction of muscle tone and discharge of less afferent impulses, the cerebral cortex remains inactive. Fatigue of the muscle with consequent reduction of transmission of afferent impulses to the cerebral cortex and thereby keeping it inactive seems to be a plausible factor in the production of sleep. Kleitman also observed that reticular formation plays an important role in the production of sleep. The afferent impulses, carried through the peripheral nerves and the spinal cord, activate the reticular formation. Activity of the reticular formation causes wakefulness. But in sleep the reticular formation remains inactive. 31
  32. 32. 5) Feed back theory of wakefulness and sleep: Once the reticular activating system is excited it is maintained for some time by the feed back impulses originated from cerebral cortex and back, peripheral muscles and back and sympathetic activity and back through liberation of epinephrine. After a prolonged wakefulness, the neuronal cells of the reticular activation system becomes unexcitable and feedback mechanism gradually fails to keep the reverberate process active- causing further depressions of the reticular activating system and sleep ensues. After a period of sleep the neuronal cells of the reticular activating system get back its excitability and if further activated by any arousal signal then wakefulness occurs with the onset of feedback process. 6) Sleep depends upon conditioned reflex: Certain conditioned stimuli causing activation of reticular formation may induce sleep. Examples for such conditioned reflexes include, cradle songs, tapping over the head and body etc. for babies and reading, massaging, brushing, softly pulling hairs, etc. for adults. 7) Stimulation of several specific areas of brain can produce sleep.Brain areas of sleep: The NREM sleep or slow wave sleep is associated with the followingcentres. 32
  33. 33. 1. The diencephalic sleep zone- is in the posterior hypothalamus and the nearby intra laminar and anterior thalamic nuclei. The stimulus frequency must be 8 Hz; faster stimuli produce arousal.2. The medullary synchronizing zone- is in the reticular formation of the medulla oblongata at the level of the nucleus solitarius. Stimulation of this zone produces sleep if the frequency is low but arousal if the frequency is high.3. Basal forebrain sleep zone- This zone includes the pre optic area and the diagonal band of Broca. It differs from the other two zones in that stimulation of the basal forebrain zone produces slow wave sleep whether the stimulating frequency is high or low.4. Raphe nuclei- These are situated in the pons, in the median plane. The serotoninergic fibers originate from these nuclei and they are involved in NREM sleep production.On the other hand the REM sleep is produced by the stimulation of the locusceruleus of pons and the noradrenergic neurons (NAgic) arising from them.In the dorsal surface of pons, in the floor of the 4th ventricle the locus ceruleusis situated. The NAgic fibers go to various areas, eg, hypothalamus/cerebralcortex/cerebellum and are intensely associated with sleep, depression andeating habits. 33
  34. 34. Factors affecting sleep: 1. Food: It is known to affect the pattern of sleep. Heavy late meals usually cause night mares. When digestion is disturbed it will reflect on the sleep and alarming dreams may occur. Coffee and tea may prolong the time taken for falling asleep as they contain caffeine. 2. Drugs: Drugs also change the pattern of sleep. Diet-pills contain stimulants and hence reduce sleep. Tranquilizers and hypnotic drugs induce and prolong sleep. Sleep induced by sleeping pills is mostly blank and dreamless. 3. Addictions: Alcohol and cigarettes affect both NREM and REM sleep. They speed up the fluctuation between these two phases of sleep. When the effect of alcohol is over, the person falls into REM sleep and that reduces possibility of deep relaxation. 4. Stimuli: External stimuli such as light and sound usually disrupt sleep. Some people find it very difficult to get sleep when the lights are on. Usually slow music in low volume is conducive to sleep but loud noises interrupt sleep. Touch also has an influence on sleep. A soft and comfortable bed promotes sleep. Rough and hard touches hinder sleep. 5. Physical/mental work: A person exhausted by physical exercises may fall asleep quickly. Serious thinking will ward off sleep. Hence it is not advisable to contemplate on serious topics at bedtime. But 34
  35. 35. monotonous mental activities such as repeated counting usually invite sleep.Sleep disorders: The sleep related disorders can be classified as follows: • Insomnia • Hypersomnia • Sleep-wake schedule disorders • ParasomniaInsomnia: The term insomnia is used to describe a condition when there is inability tofall asleep or stay in sleep or there is reduction total time of sleep. Insomnia maybe secondary, due to causes like acute hostile environment, exciting situationscontinuing for many days, or due to severe pain or due to some mental diseases.In most cases, there is no apparent cause and such cases may be called‘primary’ insomnia.Hypersomnia: Hypersomnia refers to an excessively long or deep sleep from which aperson can be awakened only by vigorous stimulation. It may be associated withconditions such as with head injury, stroke, and encephalitis. The conditionswhich can be included under this heading are narcolepsy, idiopathichypersomnolence, sleep apnoea, the Kleine-Levin syndrome. Narcolepsy: This is a condition of involuntary attacks of sleep that lastabout 15 minutes and may occur at almost any time of the day. It is an inability, 35
  36. 36. in waking state, to inhibit REM sleep. This condition is more common in males.There may be a family history of narcolepsy. It may be a genetically transmitteddisorder as an autosomal dominant trait. Patients with narcolepsy often havesecondary emotional and social difficulties, and their difficulties are increased byother people’s lack of understanding. Many etiological theories have beenadvanced but none is convincing. Idiopathic hypersomnolence: This is the most prevalent of primaryhypersomnias. Patients complain that they are unable to wake completely untilseveral hours after getting up. During this time thy feel confused and may bedisoriented. They usually have prolonged and deep night-time sleep. Almosthalf of them have periods of day time automatic behaviour, the etiology of whichis obscure. Sleep apnoea: This syndrome consists of daytime drowsiness togetherwith periodic respiration and excessive snoring at night. It is usually associatedwith upper airwau obstruction. The Kleine-Levin syndrome: This consists of episodes of somnolence andincreased appetite, often lasting for days or weeks and with long intervals ofnormality between them. Patients can always be roused from the daytime sleep,but are irritable on waking and occasionally aggressive, some are muddled andexperience depression, hallucinations and disorientation.Sleep-wake schedule disorder: Fatigue and transient difficulties in sleeping accompany changes in bodilyrhythms after travel across time zones or changes in shift worm. Regular 36
  37. 37. changes of shift or the irregular alternation of night work and days off may lead tochronic problems of poor sleep, fatigue, impaired concentration and an increasedliability to accidents.Parasomnias: The conditions which can be included under this heading are nightmaresand somnambulism. Nightmares: This is also called dream anxiety disorder. A night mare is anawakening from REM sleep to full consciousness with detailed dream recall.Night mares may be stimulated by frightening experiences during the day, andfrequent night mares usually occur during a period of anxiety. Somnambulism: This is also called sleep-walking. This is an automatismoccurring during deep non REM sleep, usually in the early part of the night. It ismost common between the ages of 5 and 12 years. Most of them do not actuallywalk, but sit up and make repetitive movements, Some walk around, usually withtheir eyes open, in a mechanical manner but avoiding familiar objects. They donot respond to questions and are very difficult to wake. They can usually be ledback to bed. Most episodes last a few seconds or minutes, but rarely as long asan hour. 37
  38. 38. Conclusion: The concept of nidra and sleep are quite comparable. The nidra is soimportant for the maintenance of health. This is true in the light of modernscientific knowledge also. According to ayurvedic concept, the kapha and tamasare responsible for the nidra; while the sleep production has been attributed tomany factors including stimulation of certain areas of brain. Ayurveda classifies the nidra on the basis of the mode of origin whilemodern classification of sleep is based on physiological variations seen inassociation with the different types of sleep. Nidra or sleep is affected by a number of factors like food, activities,external stimuli etc. Any variation in the normal sleep pattern is not at all desirable and theymay cause serious health problems which demand proper medical attention. 38