It varies. I have chronic fatigue. If I don't take my meds to wake me up, I could sleep all night and day. But I wake up frequently due to pain from medical issues, and sleep apnea. My sleep cycle is so off that I didn't go to sleep until about 2 am and had to be up at 5. So laid down this evening around 5, and slept hard til 8:30. If I have nowhere to go, I sleep throughout the day...even if I'd slept all night.