[pcthrowaway]

> rationale: without cues the circadian cycle extends up to 48h, there was an experiment about that

Do you have a link to this experiment? I haven't seen this mentioned anywhere. Studies referenced in the non-24 wikipedia page suggest natural circadian rhythms typically range from 24-25.5 hours for people not getting external cues.

[lloeki]

I had to do a quick search again, this is the guy:

https://en.m.wikipedia.org/wiki/Michel_Siffre

Here's an interview on the subject, which includes the initial experiment (which had him having a slightly over 24h rhythm) and subsequent ones (where the 48h rhythm showed up)

https://www.cabinetmagazine.org/issues/30/foer_siffre.php

The interesting thing about going down a cave is that it removes a ton of other possible cues like temperature variation (or side effects of trying to mechanically account for that)

My pet theory about human beings generally having slightly longer than 24 hour circadian rhythm is that it gives margin: with a 24 sun cycle and a 24.5 rhythm you naturally get a self-correcting consistent positive benefit; otherwise you'd always be right on the edge and unable to recover when things go sideways.