I am regular reader of yogaforums.com and I recently found this interesting question by saumitra about Siddhasana. She experienced that while practicing Kapal bhati and anulom vilom sitting in Siddhasana position; she feel that her entire left feet numb as restricted blood flow.
Find her question in details here:
What you suggest to Saumitra, so that she can get rid from this issue.
Namaste.
Here is one detailed video demonstrate how to practice Siddhasana effectively.
Saumitra,
I strongly recommend to consult some yoga teacher in your area and show him how you perform Siddhasana. It may happen that the way you are practice may be wrong. If you still face this problem, better you practice kapalbhati and anulom vilom in normal posture.
You should consult physio if you keep facing this problem.
Lets see, what other yoga experts advice !
Namaste !