कुम्भके कुम्भवत्कालमनन्तं परितिष्ठति ।अभ्यासात्स्तम्भिते प्राणे प्राणस्पन्दो निरुद्ध्यते
In plain words
In kumbhaka, [prāṇa] stands like a jar for an endless span of time; when, through practice, prāṇa has been held fixed -- the vibration of prāṇa is restrained.