यद्वै तत्पुरुषे शरीरमिदं वाव तद्यदि-दमस्मिन्नन्तः पुरुषे हृदयमस्मिन्हीमे प्रा-णा प्रतिष्ठिता एतदेव नातिशीयन्ते ॥ ४ ॥
In plain words
Whatever that bodily form in the person is, that indeed is this heart located within the inner person. For within this heart these vital breaths are established, and they never exceed it.
Close to the Sanskrit
Which indeed that body in the person is, this indeed is that. Whatever is in this inner person the heart, in this indeed these breaths are established, this very thing they do not exceed.