Bhashya
यद्वै तत्पुरुषे शरीरं गायत्री इदं वाव तत् ।यदिदम-स्मिन्नन्तः मध्ये पुरुषे हृदयं पुण्डरीकाख्यम् एतद्गायत्री ।कथ-मिति, आह-अस्मिन्हीमे प्राणा प्रतिष्ठिता, अतशरीरवत् गायत्री हृदयम् ।एतदेव च नातिशीयन्ते प्राणा ।'प्राणो ह पिता ।प्राणो माता' 'अहिंसन्सर्वभूतानि'इति श्रुते भूतशब्दवाच्या प्राणा ॥
In plain words
Whatever that body in the person is, the Gāyatrī is indeed that. And whatever is located right in the center of the person, within the heart known as the lotus—that is the Gāyatrī. How so? The text answers: Because within it these vital breaths are established, the heart is Gāyatrī, just like the physical body. And the breaths never exceed it. As the scriptural passages state: 'Prāṇa is truly the father, prāṇa is the mother,' and 'Not injuring all beings'—thus the vital breaths are designated by the word bhūta.
Close to the Sanskrit
Which indeed that body in the person is, Gāyatrī this indeed is that. Whatever is in this inner middle person the heart known as lotus, this is Gāyatrī. How, it says: In this indeed these breaths are established, therefore like the body the heart is Gāyatrī. And this very thing the breaths do not exceed. 'Prāṇa indeed is father. Prāṇa is mother' 'Not injuring all beings' thus from the śruti the breaths are designated by the word bhūta.