CC Antya 6.310

sāḍe sāta prahara yāya kīrtana-smaraṇe
āhāra-nidrā cāri daṇḍa seha nahe kona dine
Synonyms: 
sāḍe sāta prahara — 75 praharas (one prahara equals three hours); yāya — is spent; kīrtana-smaraṇe — in chanting the Hare Kṛṣṇa mahā-mantra and remembering the lotus feet of Kṛṣṇa; āhāra-nidrā — eating and sleeping; cāri daṇḍa — four daṇḍas (one daṇḍa equals twenty-four minutes); seha — that; nahe — is not; kona dine — some days.
Translation: 
Raghunātha dāsa spent more than twenty-two hours out of every twenty-four chanting the Hare Kṛṣṇa mahā-mantra and remembering the lotus feet of the Lord. He ate and slept for less than an hour and a half, and on some days that also was impossible.