According to Jai Deva Singh, a scholar of this text (2010), the verse also points to another practice: ajapa japa - the universal mantra [hamsa or soham] made effortlessly and automatically by the flow of the breath in every living being moment by moment. The mantra repeats ceaselessly with the breath, and this verse invites us to notice and join, becoming aware of the inherent interconnection of the individual self and the Timeless Self.
To begin with we notice: ham sounding silently on the inhale, and saha sounding silently on the exhale [That I Am]; over time this may shift organically to so-ham [I am That]. The interpretation below is an excerpt from Lorin Roche's Radiance Sutras
Beloved, your questions require answers that come through direct living experience.
The way of experience begins with a breath, such as the breath you are breathing now...
Exhaling, breath is released and flows out. There is a pulse as it turns to flow in.
In that turn you are empty. Enter that emptiness as the source of all life.
Inhaling, breath flows in, filling, nourishing. Just as it turns to flow out, a flash of pure joy
Life is renewed.