One verse

Srimad Bhagavatam 4.23.6

4.23.6

ग्रीष्मे पञ्चतपा वीरो वर्षास्वासारषाण्मुनि: । आकण्ठमग्न: शिशिरे उदके स्थण्डिलेशय: ॥ ६ ॥

grisme panca-tapa viro varsasv asarasan munih akantha-magnah sisire udake sthandile-sayah

grisme
in the summer season
panca-tapah
five kinds of heating
virah
the hero
varsasu
in the rainy season
asarasat
being situated within the torrents of rain
munih
like the great sages
akantha
up to the neck
magnah
drowned
sisire
in winter
udake
within water
sthandile-sayah
lying down on the floor.

Following the principles of forest living and the footsteps of the great sages and munis, Prthu Maharaja accepted five kinds of heating processes during the summer season, exposed himself to torrents of rain in the rainy season and, in the winter, stood in water up to his neck. He also used to simply lie down on the floor to sleep.