Rules Of Pranayama

Some rules for Pranayam
Select a clean and peaceful place for doing Pranayama. If possible, choose a place near a clean pond or river.
As there is a lot of pollution in the cities, some kind of incense can be lit like Guggulu and purified butter, to create a clean environment at that place, igniting a lamp with purified butter only, can also serve the purpose.
Sit either in any of the Asanas, viz. Padmasana, Sidhasana or Vajrasana, which ever you find convenient. The sheet or cloth (cotton or wool etc.) on which you sit must be a non-conductor of electricity.
Breathe only through the nose, because by doing so the air which you take in, is filtered. During daytime when you are not sitting for the performance of Pranayama make it a habit to do respire only through nose and not through mouth. Nasal respiration keeps the temperature of the Nadis (Vessels) –'Ida',Pingala and 'susmana' even. It also prevents foreign and harmful objects from getting into lungs.
Like ‘Yog’, Pranayama should also be performed four or five hours after taking food. In the morning Pranayama should be done after finishing daily routine acts like cleansing mouth, emptying of bowels etc., it should also be done before Yogsana. In the beginning Pranayama should be done for five or ten minutes gradually the time may be increased up to about 1/2 or 1 hour. Maintain a specific number of repetitions and do not variate. Maintain a specific rhythm. If it is not possible to clean the bowels by morning, at night take some mild laxative like terminalia chebula (Indian Hardaya) or any other mild laxative (a non habit forming medicinal herb having a laxative effect). Kapala-bhati Pranayama, if done regularly for a few days will help in curing constipation.
Keep your mind calm and composed. However, Pranayama can also calm down the disturbed mind and keep one happy.
Methods of Pranayama may be varied according to the seasons and your own physical make up and mental attitude. Keep this in mind and modulate the method accordingly. Some Pranayama increase the body temperature, whereas, some bring it down. Some Pranayama maintain the temperature at the normal level.
If you feel fatigued in the course of doing Pranayama , rest for sometime and then begin deep breathing, which will remove the fatigue.
Pregnant women, hungry persons, persons suffering from fever and those who are lustful having no control on their passions should not do Pranayama . If you are sick, keep in mind the instructions to be followed by sick persons while during Pranayama.
For prolonged exercises of Pranayama, observance of celibacy is necessary. Besides, food should be simple not containing irritating spices. It should be ‘Sattvika’ – (Plain and simple, non-spicy food). Use of cow’s milk, ghee (clarified butter), fruits and green vegetables can be said to be ideal food. Moderation also is a good rule to observe.
Do not strain yourself while doing ‘Kumbhak’ i.e. retaining the breathed air inside or keeping the air out after exhaling (Breathing in is called ‘puraka’, retaining the breathed air in is called ‘Kumbhak’ and exhaling the air is called ‘Recak').
Pranayama does not mean just breathing in, keeping the breathed air in and exhaling it. It also means establishing control on the entire breathing process, and maintaining mental equilibrium, and concentration of mind.
It is beneficial to chant the mantra (a group of words that carry vibrations and energy) Om (the first cosmic soundless sound), aloud and repeat the same several times before doing Pranayama. Even recital of sacred songs in the praise of almighty God or recital of some sacred hymns may be beneficial. This will calm your mind and make you fit for Pranayama, because a peaceful mind is very essential while doing Pranayama . Mental or loud recitation of Gayatri Mantra (considered as one of the greatest mantra, used in meditation and also for chanting) or any other sacred hymn brings spiritual benefits to the Sadhaka.
See that while doing Pranayama , none of your organs such as mouth, eyes, nose, etc. feels any strain and it should be done gradually without any undue stress or strain. All the organs of the body should be kept in normal condition. While doing Pranayama sit in an erect posture. Keep your spine and neck straight. This is essential for reaping the full benefit of Pranayama .
If possible Pranayama should be done after your usual morning functions like cleansing of mouth, evacuation of bowels, bathing etc. However, if it becomes necessary for you to take bath after Pranayama , keep an interval of about 15 to 20 minutes between Pranayama and bathing. For acquiring proficiency in Pranayama do not depend on books or what is done and preached by others. Seek the guidance of an expert and do Pranayama under his direct supervision.
Different treatise advocating or dealing with the subject of Pranayama describe several methods and each of them has its own importance. However, it is not possible for most people to do all these exercises daily. Hence, with the blessings of our teachers and in view of our experience, we have evolved seven methods of Pranayama , which incorporate into themselves, almost all the peculiarities of Pranayama rendering them scientific and useful from a spiritual point of view. All these seven types of Pranayama can be done, as a routine and in a time bound programme of about 20 minutes. The person who does these exercises daily and regularly can attain following benefits which are briefly described as under:
All the three Doshas (Humors) - Vata , pitta and Kapha get adjusted in proper proportion and abnormalities in them are removed.
Digestive system improves and diseases pertaining to digestive organs are cured.
Diseases pertaining to lungs, heart and brain are also cured.
Obesity, Diabetes, Cholesterol, Constipation, Flatulence, Acidity, Respiratory troubles, Allergy, Migraine, High blood pressure, diseases pertaining to kidneys, sexual disorders of males and females etc. are also cured.
Resistance against diseases is stepped up. Immunity develops.
Hereditary diseases like diabetes and heart disease are can be avoided.
Falling of hair or its premature graying, appearance of wrinkles on face or other parts of the body at young age, diminution of eye sight, forgetfulness, etc. are relieved and process of aging is retarded.
Face becomes bright, luminous and calm.
Energy Chakra are cleansed and enables the practitioner to awaken the Kundalini.
Mind becomes stable and tranquil. A sense of contentment and enthusiasm or zeal develops. Conditions like depression are relieved.
Performance of yogic exercises like meditation will be easy.
All the diseases of the physical and etheric bodies will be cured. Freedom from negative and harmful mental conditions like anger, lasciviousness, greed for money, arrogance etc. will be achieved.
All the physical and mental disorders and abnormalities are cured and toxins eradicated from the body.
Freedom from negative thinking is achieved and the mind develops the habit of positive and constructive thinking.

Courtesy : http://www.divyayoga.com