The speaker keeps returning to one image, the breath from their lungs, and uses it to show what they have given away over a lifetime. First it goes to someone they wanted to make smile, even while holding back sobs as a child. Then it goes to a girl they chased and caught before she reached the street, and to a time of laughter under a star-speckled ceiling. Breath here stands for care, energy and love.
The fourth stanza is the darkest. The speaker says they "stole" their breath on a day when they felt it wasn't needed anyway. The poem doesn't explain this, but it hints at a moment of despair. After that, the tone shifts. The speaker decides their story isn't over and finally gives the breath to themselves. The mood moves from tender and sad to determined, ending on a plain, confident claim: "This life is mine / And it I will live."