Pranayama and Breath

I used to find Pranayama Deep Breathing, the start of a Bikram class, very difficult and challenging.  I now enjoy the breathing exercise, it fills me with energy.  

As I experiment with the breath in Ashtanga yoga, it reminds me that finding the breath can be difficult and challenging and that being aware of each breath brings focus to the practice.

I am re reading Iyengar's Light on Life and I like Mr Iyengar's insight on Pranayama:

"Yogic breathing techniques are meditative in their origin and in their effect.  They basically consist of four parts.  They are inhalation (puraka), retention of the breath after inhalation (antara kumbhaka), exhalation (recaka) and retention after exhalation (bahya kumbhaka).  The in-breath should be long, subtle, deep, rhythmic, and even.  The energizing ingredients of the atmosphere  percolate into the cells of the lungs and rejuvenate life.  By retaining one's in-drawn breath, the energy is fully absorbed and distributed to the entire system through the circulation of blood.  The slow discharge of air in exhalation carries out accumulated toxins.  By pausing after the out-breath according to one's capacity, all stresses are purged and drained away.  The mind remains silent and tranquil."

"It is impossible , when we turn our attention to the inner movement of breath, to use our senses externally at the same time.  You cannot also be thinking that you must stop at the supermarket on the way home after work.  Pranayama is the beginning of withdrawal from the external engagement of the mind and senses.  That is why it brings peacefulness.  It is the hinge between extroversion and introversion" 

The second paragraph I find to be very true in my Ashtanga practice.  I have had moments where my mind has wandered, in my home practice, and I have lost everything.  My balance, the asana, my breath.  When I stopped and found my breath and focus I was able to continue.