I was reading through Sri Ravi's wonderful Lalita Sahasranama commentary and saw this under name 333:
"There is a nāḍi (nerve) called vāruṇi which can be controlled by breath. This nāḍi plays a significant role in excretion of bodily waste. If this nāḍi is brought under control by proper breathing exercises, one will never feel tiredness in the body. Sages keep this nāḍi under their control to cope up with longer duration of meditation. She is said to be in form of this nāḍi. This is also known Vāruṇi Vidyā, referred in Taittirīya Upaniṣad (III.vi), which says “seṣā bhārgavī vāruṇī vidyā सेषा भार्गवी वारुणी विद्या” which refers to the knowledge sage Bhṛgu acquired from Varuṇa; the knowledge referred in the Upaniṣad is about resting in the empty space of the heart (referring to khecarī mudrā or the effect of using khecarī mudrā)."
Does anyone have any experiences with this nadi, specifically with it's effect on physical exhaustion? Are there specific mantras/ or pranayams that are used for this purpose? Thank you so much
This is a very useful question. The effects of Varuni naadi is exactly as described by you. In olden days, there were yoga practices called "kriya". These were done to control the nadis through external forces. Once used to external, we would be able to control from inside.
These kriyas are to be very effective in internal cleaning and control. But now a days its very difficult to find people doing these kriyas.