Shloka 54
इन्द्रस्य दुःखप्राप्तिः—त्रिशिरोवधः, वृत्रोत्पत्तिः, जृम्भिकाजननम्
Indra’s Distress: Slaying of Triśiras, Birth of Vṛtra, and the Origin of Yawning
स्वान्यड्रान्यभिसंक्षिप्य निष्क्रान्तो बलनाशन: । ततः प्रभूृति लोकस्य जृम्भिका प्राणसंश्रिता
svāny aṅgāny abhisaṅkṣipya niṣkrānto balanāśanaḥ | tataḥ prabhṛti lokasya jṛmbhikā prāṇasaṃśritā ||
シャリヤは言った。「自らの肢体を引き寄せ、身を縮めて、敵の力を滅ぼすインドラはするりと外へ抜け出た。その時以来、あくびの力（jṛmbhikā）は、あらゆる生きものの生命の息（プラーナ）のうちに宿るようになった。」
शल्य उवाच
Educational Q&A
Even ordinary bodily phenomena are presented as rooted in cosmic history: the verse links a universal impulse (yawning) to prāṇa, suggesting that life-breath pervades all beings and that self-mastery and timely contraction/withdrawal can be a means of protection and success.
In a mythic account, Indra is described as escaping by contracting his limbs; thereafter, the force called jṛmbhikā (yawning) is said to have taken residence in the life-breaths of all people, explaining why yawning is universal.