Next, when he is in profound sleep, and knows nothing, there are the seventy-two thousand arteries called Hita, which from the heart spread through the body. Through them he moves forth and rests in the surrounding body. And as a young man, or a great king, or a great Brahmana, having reached the summit of happiness, might rest, so does he then rest.

In plain words: Agatasatru explains that in deep, dreamless sleep, when a person knows nothing, the self moves through 72,000 channels called Hita that spread from the heart through the body, and rests there. It rests as peacefully as a young man or a great king at the height of happiness.