BAHYA ABHYANTARA STHAMBHA VRITTIH DESHA KALA SANKHYABHIH PARIDRISHTO DIRGHA SUKSHMAH ||50||

बाह्याभ्यन्तरस्थम्भ वृत्तिः देशकालसन्ख्याभिः परिदृष्टो दीर्घसूक्ष्मः ॥५०॥

bāhya-ābhyantara-sthambha vṛttiḥ deśa-kāla-sankhyābhiḥ paridṛṣṭo dīrgha-sūkṣmaḥ ||50||

Exhalation, inhalation, retention, technique, time and number must be very precisely regulated over a lengthy period. ||50||


bāhya = external; exhalation 
abhyantara = internal; inhalation 
stambha = steadiness; restraint; suspension; stationary 
vṛttiḥ = (nom. from vṛtti) wave; thoughts; thought waves; movement
deśa = place; technique 
kāla = time
saṁkhyābhiḥ = (nom. from saṁkhyābhi) number; mathematics 
paridṛṣṭo = (from paridṛṣṭa) measured; regulated; precisely observed; verified 
dīrgha = long; extended 
sūkṣmaḥ = (nom. from sūkṣma) subtle; fine