Being Asleep by 8 P.M. and Waking at 4 A.M.

https://www.psychologytoday.com/us/blog/the-athletes-way/201908/is-being-asleep-by-8-pm-and-waking-at-4-am-a-disorder

Napping https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod7/05.html