Even saintly persons like Bhṛgu, born previously, could not perform such severe austerities, nor will anyone in the future be able to do so. Who within these three worlds can sustain his life without even drinking water for one hundred celestial years?
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
नैतत्पूर्वर्षयश्चक्रुर्न करिष्यन्ति चापरे । निरम्बुर्धारयेत्प्राणान् को वै दिव्यसमाः शतम्
naitatpūrvarṣayaścakrurna kariṣyanti cāpare | niramburdhārayetprāṇān ko vai divyasamāḥ śatam
SB 7.3.19