(1) Before practising a'sanas, do vya'paka shaoca or take a full bath. Vya'paka shaoca must also be done before daily meditation; if a'sanas are done with daily meditation then it is not necessary to do vya'paka shaoca separately.
(2) Do not practise a'sanas in an open place, because it may result in sudden exposure and thereby you may catch cold. While practising a'sanas indoors, attention should be paid to keep the windows open so that air can pass through.
(3) No smoke should be allowed to enter the room. The less smoke the better.
(4) Males must wear a Kaopiina (laungot'a'), and there should be no other clothing on the body. Females must wear tight-fitting underwear and a bra.
(5) Practise a'sanas on a blanket or a mat. Do not do a'sanas on the bare ground, because you may catch cold, and some secretions which come from the body while practising a'sanas may be destroyed.
(6) Practise a'sanas only while breath is flowing through the left nostril or both nostrils; do not practise a'sanas when the breath flows only through the right nostril.
(7) Take sa'ttvika food. But a person for whom it is difficult to give up ra'jasika food can for the time being take a small piece of myrobalan (it is better to use the small type of myrobalan), or something of a similar nature, after meals. However, this procedure does not apply in cold countries.
(8) Do not cut the hair of the joints of the body.
(9) The nails of the fingers and toes must be kept cut short.
(10) Do not practise a'sanas on a full belly. It is prohibited to perform a'sanas for two-and-a-half to three hours after a meal.
(11) After practising a'sanas, you should massage your arms, legs and entire body, especially the joints, very well.
(12) After the massage is finished, remain in shava'sana (corpse posture) for at least two minutes.
(13) After shava'sana do not come in direct contact with water for at least ten minutes.
(14) A practitioner of a'sanas should not massage his or her body with oil. If you like you may rub oil lightly over the body.
(15) After practising a'sanas, it is desirable to walk in a solitary place for some time.
(16) Just after a'sanas pra'n'a'ya'ma is prohibited.
(17) If it is necessary to go outdoors after practising a'sanas and if at that time the body temperature has not come down to a normal level, or if there is any difference between the room temperature and the outside temperature, you must cover your body when going out. If possible, inhale a deep breath inside the room and exhale it after coming outside. In that way there will be no chance of catching cold.
(18) It is not prohibited for the practitioner of a'sanas to practise free-hand exercise, running or sports, but just after a'sanas all these are prohibited.
(19) There is no restriction of nostril for the following a'sanas: padma'sana (lotus posture), siddha'sana (siddha posture), ardhasiddha'sana (half siddha posture), bhojana'sana (cross-legged sitting posture), viira'sana (viira posture), diirgha pran'a'ma (long bowing posture), yoga'sana (yoga posture) and bhu'jaunga'sana (snake posture).
(20) For all those a'sanas where there is no restriction of nostrils, there is no restriction on food either.
(21) During menstruation, pregnancy and within one month of delivery, women must not practise a'sanas or any other exercise. The a'sanas for dhya'na can be done under all conditions -- padma'sana, siddha'sana and viira'sana are the proper a'sanas for dhya'na and dha'ran'a'.
(Official source: Carya'carya Part 3, by Shrii Shrii Anandamurti)
