Your most valuable possessions for Yoga -Agni and Prana
When I asked my yoga teacher in India about what other material I should add for the course content of "The subtler dimensions of asana practice", he told me that I should write an article on the Jatara Agni (the body's fire) and Prana (the body's life force). He said everything else at best is secondary. This article is a product of that suggestion. It is written with various scriptural references about the importance of this fire in all aspects of yoga.
Throughout the yogic scriptures, Ayurveda and the Vedic scriptures, the Jatara agni (जठराग्नि) and the Prana get very important mentions. In Ayurveda, treatment of diseases is done through normalizing this Jatara Agni and the flow of Prana.
In Hatha yoga, the body is compared to a clay pot that is decaying because it is immersed in water. This Jataragni strengthened by yoga, is compared to a fire used to bake this pot to make it strong (Gheranda Samhita).
2) The sound of Prana
Chandogya Upanishad describes the sound of the agni and the prana as a tool for meditation. It is thought that when one closes the ears, the rumble that one hears is said to be the sound of the body's fire.
Chandogya Upanishad III-xiii-7
तस्यैषा दृष्टिर्यत्रितदस्मिञ्छरीरे संस्पर्शेनोष्णिमानं विजानाति तस्यैषा श्रुतिर्यत्रैतत्कर्णावपिगृह्य निनदमिव नदथुरिवाग्नेरिव ज्वलत उपशृणोति तदेतद्दृष्टं च श्रुतं चेत्युपासीत चक्षुष्यः श्रुतो भवति य एवं वेद य एवं वेद
॥ इति त्रयोदशः खण्डः ॥
tasyaiṣā dṛṣṭiryatritadasmiñcharīre saṃsparśenoṣṇimānaṃ vijānāti tasyaiṣā śrutiryatraitatkarṇāvapigṛhya ninadamiva nadathurivāgneriva jvalata upaśṛṇoti tadetaddṛṣṭaṃ ca śrutaṃ cetyupāsīta cakṣuṣyaḥ śruto bhavati ya evaṃ veda ya evaṃ veda
III-xiii-7: Again, the light of Brahman that shines above this heaven, above everything, above all, in the incomparably good and the highest worlds, even this is the light within the body of man. This light can be seen inasmuch as one has a perception of warmth when one touches the body. It can be heard inasmuch as, on closing the ears, one hears something like the sound of a chariot or the bellowing of a bull, or the sound of a blazing fire. One should meditate on the light as seen and heard. One who meditates on this thus, becomes beautiful and illustrious - yea, one who meditates thus.
Yoga Sutra 3.23 talks about the portents of death. The commentaries on the yoga sutras elaborate on this to include the absence of the sound of prana. The above asana is Garba Pindasana or Embryo in the womb pose. Here we close the ears and listen to the sounds inside.
3) Vaishvanara - the digestive fire
Another name for the Jatara Agni is Vaishvanara. In chapter 15 of the Bhagavad Gita, Bhagavan Krishna says,
अहं वैश्वानरो भूत्वा प्राणिनां देहमाश्रित: |
प्राणापानसमायुक्त: पचाम्यन्नं चतुर्विधम् || 14||
ahaṁ vaiśhvānaro bhūtvā prāṇināṁ deham āśhritaḥ
prāṇāpāna-samāyuktaḥ pachāmy annaṁ chatur-vidham
Becoming the digestive fire, Vaishvānara, I reside in the bodies of all beings. Associating with Prana and Apana, I digest the four types of food (1. Bhojya - Foods that are chewed, such as bread, chapatti, etc. 2. Peya - These are mostly liquid or semi-solid foods which we have to swallow or drink, such as milk, juice, etc. 3. Kośhya - Foods that are sucked, such as sugarcane. 4. Lehya - This includes foods that are licked, such as honey, etc.)
As shown in the section on Agni, in "The Subtler dimensions of Asana Practice", the fire if not strong, will not be able to completely metabolize food and the un-metabolized food is deposited as Ama (waste material) in the body. For the same reason, eating heavy and excess food also douses the fire just as sand thrown on fire douses it, and makes the body susceptible to illness (Please see the video below). If the fire is strong, the body has a higher resistance to illness. The three imbalances in the body's fire area shown below.
4) Tips in asana practice to maintain the Agni
Those who maintain a regular hatha yoga practice, such as Ashtanga Vinyasa Yoga, will be aware of the following guidelines to maintain the Agni during practice.
5) The secret to prowess in asanas
The ultimate secret to prowess in asanas that my teacher was referring to is not obtained by doing more and more brute force practice, but by clearing the obstacles to the flow of prana (Ref: Prowess in poses).
6) Flexibility vs Malleability in asana practice
Flexing a metal into various shapes using heat
In Hatha Yoga, the Ujjayi breath is used to generate heat. The Bandhas are thought to channel this heat using the Prana (Ref: Flexibility vs Malleability in asana practice). Even if one is not flexible, one is said to become malleable in Hatha Yoga just the way a heated metal sheet can easily be flexed into various shapes.
7) Diet : The cornerstone for all yoga practices
If there is one aspect that is emphasized throughout the scriptures to attain success in yoga, it is a light and moderate quantity diet. This is called Hita Mita Ahara (appropriate and moderate quantity food). A vegetarian diet is also suggested for various reasons in this article. More information can be found in the articles below:
1) The Yogi, the Bogi and the Rogi: Ancient wisdom on achieving depth in Asanas
2) An empty stomach has one problem; A full stomach has a 100 problems: Diet and Yoga wisdom from ancient texts
3) The most compelling link between Yoga and Diet in the scriptures
Yoga is big business these days primarily associated with asana practice. Even though there are many workshops on how to do fancy handstands and backbends, the truth to attaining success in any branch of yoga has less to do with doing more than to do with doing (eating) less and clearing the obstacles to the flow of Prana (Yoga Sutra 4.2). This article is a summary of previous articles about the two main ingredients for success in yoga - Agni and Prana.