Ethymology and Definition
Nivritti निवृत्ति (nivṛtti). Return, disappearance, abolition, prevention, cessation, abstaining or desisting from; ceasing from worldly acts. This term is often considered with its counterpart 'pravritti', the latter meaning 'social action' and nivritti 'inward contemplation'. This technique is called 'Non-breathing'.
This is a breathing through which energetic breathing is sought.
Neither the thorax nor the abdomen move. It is through the throat that air is sipped up to the heart and then expel it through the nose. The breathing is therefore very short. The abdomen is slightly contracted in uddiyana bandha.
Only this tiny circulation of air must be felt, without restrictions. This minute amount goes in an out quickly.
It is in these conditions that the energy, the subtle breath, can be generated.