I ran sleeper team for years. It's probably been 30+ years since I went 11 Western then retired from driving in the late 90's but the built in clock still is ticking. If I can get 6 hours continuous I'm happy as hell.I'm 67, I retired 10 years ago at 57. I drove truck for 34 years mostly at night (freight hauler).
I also have farmed our 90 acres, since we bought this place in 1994.
I have broken sleep, usually awake after 4 hours of sleep, very unusual for me to sleep straight 6 hours.
Always up by 4am and up until 9pm or 10pm.