that’s not always the case unfortunately, and when it is the case, it still requires an insanely high control pause - at least 180 sec
In the Buteyko’s lecture at MSU, it’s mentioned that there’s an old man with CP of 240s and even he needs 4 hours of sleep
The only other person who reported 2 hours of sleep was Buteyko himself at 180cp
Other than those two, I know one guy with >180CP and he sleeps 6-8 hours. He never did Buteyko though, he achieved this control pause through yoga and pranayama, raising kundalini, etc., VERY advanced dude
And I also read about a woman on some Russian forum. She never mentioned sleep or control pause but she had some insanely high results at the Frolov breathing device - 120s PRA which corresponds to some >120s CP. She reported that the needs for food and drink have lowered drastically, never mentioned sleep
I myself got to 60s of morning CP when was obsessing about Buteyko, and my sleep was about 5 hours on average. Yet I know people with similar numbers whose sleep didn’t decrease at all.
It seems that with sleep it’s hit or miss - reduces for some, doesn’t reduce for others.
EDIT: TRE can reduce sleep though. David Berceli, the creator of TRE, mentioned that he doesn’t even sleep every night anymore. Don’t know how true that is. After over a year of TRE, my sleep is still 7-9 hours