When the active self of a person, tired in body and mind, loses touch with his worldly affairs, sleep comes to him.
Hence, one should not sleep in the day,nor keep late hours. Having known both these acts to be injurious, the wise should observe moderation in sleep. A conformity to the preceding rule of conduct is rewarded with health, good humour, strength, healthful complexion, virility and beauty, a frame which is neither too fat nor too thin,and a long life of a hundred years). A day sleep may not prove injurious to those who are habituated to it and conversely keeping late hours at night may not tell upon the health of those to whom it is customary. 37-39
An aggravated condition of the bodily Váyu or Pittam, an aggrieved state of the mind, loss of vital fluid, and a hurt or an injury may bring on insomnia, the remedy being the adoption of measures antagonistic to those which destroy sleep. The following measures are useful in cases of sleeplessness - such as anointing the body, rubbing of oil on the head, soft massages of the body (with cleansing paste) and shampooing; a diet consisting of cakes and pastry made up of Sáli-rice and wheat prepared with sugar or other derivatives of sugarcane, sweet or soothing articles with milk or meat juice or flesh of animals of the Biskira or Viles'aya class, and eating of grapes, sugar and sugar-cane at night, are beneficial (in such cases;; so also a soft and pleasant bed, and easy and convenient seats and means of locomotion. Hence, a wise physician should advise those and similar other measures to allay insomnia. 40-41.
Excessive sleep should be remedied by emetics, Sans'odhana measures, fastings, bleeding, and works which tend to disturb the mental equanimity of man. Keeping up at night is beneficial to persons afflicted with obesity, poison or the deranged Kapham; so also a nap in the day is beneficial to people troubled with hiccough, colic pain, dysentery, indigestion, or thirst. 42-43.
In this kind of light sleep, or in the preliminary stage of sleep, the sense organs are overpowered and remain only partially cognisant of their respective objects and all (subjective and objective) symptoms of a sleepy person such as, yawning, sense off atigue and heaviness of the limbs, present themselves in succession; these are the special features of Tandrá. One (prolonged) inhaling of the air through a widely open mouth and subsequent exhaling with the contraction of the limbs and tearful eyes are (all together) called Jrirnbhá or yawning.
A sense of fatigue without any physical labour which comes upon a person unaccompanied by hurried respiration is called Klama It obstructs the proper functions of the senses as also the workings of the active organs. * An inordinate love of pleasure and a great aversion to pain, attended with an apathy to all sorts of work even with the capacity of carrying them through is called Alasyam (laziness) Nausea, without vomiting of ingested food, attended with salivation and formation of sputum, and cardiac distress are the symptoms of Utklesham. A sweet taste in the mouth, drowsiness, a beating pain in the heart, dizziness, and non-relish for food are the signs of Grláai (languor). A feeling as if the whole body were wrapped in a wet sheet, accompanied by an extreme heaviness of the heart, is called Gauravam. 44-50.
* Hand, leg, anus, and generative organ etc.
Loss of consciousness (Murchchá) is due to an excess of the deranged Pittam and to the quality of the Tamas; vertigo (Bhrama) is due to an aggravated state of the Váyu, Pittam,and to the quality of the Rajas; drowsiness (Tandrá) is due to a similar condition of the Váyu, Kapham and to the quality of the Tamas; while sleep (Nidrá) is produced by the predominance of Kapham and to the quality of the Tamas in the organism. 51.
The growth of a foetus in the womb is effected by the serum (Rasa) prepared out of the food (assimilated by its mother) incarcerated by the Váyu in the internal passage of its body. 52.
Be it clearly understood that there exists fire or heat(Jyoti) in the umbilical region of the foetus which is fanned by its bodily Váyu and thus contributes to the growth of its body. The same Váyu in combination with the heat (thus generated), expands the upward, downward, and lateral channels (in the body of the embryo) and thus leads to the growth of the foetus. The eyes (Dristi - aperture of sight) and the hair-follicles of a man do not participate at all (in the general expansion of the body). This is a law of nature, and is the opinion of Dhanvantari. On the other hand the growth of hair and finger nails continue even when the body enters the stage of decay. This also is a law of nature. 53-56.
* In the text we find the word "Indriya" which refers to both Jnánendriya (sensory functions) and Karmendriya (motor functions) of the body.