3.6

Translation by Swami Sivananda
6 The atman dwells in the heart, where there are one hundred and one arteries (nadi); for each of these there are one hundred branches and for each of these branches, again, there are seventy two thousand subsidiary vessels. Vyana moves in these.

Translation by Max Mueller
6. The Self is in the heart. There are the 101 arteries, and in each of them there are a hundred (smaller veins), and for each of these branches there are 72,000. In these the Vyâna (the back-breathing) moves.