It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that when sleep overcame him during the night prayer (qiyam al-layl), he would come to his bed and lie down, then sleep like a bird (briefly), then spring up, perform ablution and resume praying.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 587