Musannaf Ibn Abi Shayba 1:1409

Waki’ narrated to us, from al-A’mash, from Ibrahim, from al-Aswad, from ‘Aisha, who said: The Prophet (peace and blessings of Allah be upon him) used to sleep until he would breathe heavily (snore), then he would get up and pray, and he would not perform ablution.