Hello VIL and All:
The primary focal point of Spiritual Self-Realization, in my view, is ultimately the Self-Cultivation and Transformation of Consciousness. This may seem to be stating the obvious, yet getting to that focal point...and staying focused there...is oftentimes quite challenging. This is often especially true for novices, who new to the training practices. Stumbling blocks may seem to be everywhere!
Not the least of these stumbling blocks is the condition of the physical body at the commencement of the training. So long as the physical body remains unhealthy and unfit, a Sadhaka's overall physical condition can be a great impediment to the spiritual process by serving as a source of mental distraction and energy depletion which demands almost constant attention. This is often a major reason why many new practitioners fall away from their Sadhana, IMO.
For example, seated meditation is too difficult, even for short periods of time, due to lack of sufficent physical flexibility to comfortably assume and maintain the seated asanas usually recommended for the practice. Ditto for Hatha Yoga routines...it hurts!
Pranayama feels too difficult because of respiratory allergies, past or present cigarette smoking, or because of high levels of air pollution or chemical toxins in the practitioner's living or work environment. Dietary modifications are seen as undesirable, even though certain foods might be a cause of current health problems....so forget making those changes, and so forth. The list of physical impediments to establishing and consistently maintaining a self-disciplined Sadhana, and the list of excuses for not resolving these apparent impediments, goes on and on and on...ad infinitum et nauseum!
So virtually everyone initially requires some amount of chemical detoxification, blood purification, internal organ cleansing, and physiological strengthening, as well as a certain amount of stretching and loosening in order to free the mind of distraction regarding the physical body and its various functions. Hatha Yoga wisely incorporates highly effective, time proven techniques intended specifically for these purposes.
Cleansing and purification are also needed to open the Nadis and Chakras, and to refine, consolidate, compress, and store the Prana internally, and to gradually awaken and circulate the Kundalini Shakti. This intrinsic energy purification and cleansing, however, would appear to be more directly related to the real agenda priority of Cultivating and Transforming Consciousness than is the physical purification. Here we are addressing energetic refinement, rather than athletic conditioning and physiology. As such, mental modifications are the top priority. Whatever methods or tools that can be employed to get rid of that "stinkin' thinkin'..." and to eliminate 'toxic' thoughts and emotions, will refine the Prana and liberate the Kundalini, IMO.
Perhaps some more thoughts on this later, as I am off and away now to heal the sick and injured, and to raise the damned near dead back to life!
Hari OM!
Doc