If you are able to make relatively few commitments for a month, go to sleep when you feel tired. Sleep as much as feels good. Track it in a spreadsheet.
Some people with non-24 have very regular sleep/wake cycles. I'm not as fortunate, but in the winter will tend towards 24-29 hour days, with an average just over 27 (perhaps this winter has even been a little under 27 as I've been more physically active)
In the summer it's close enough to 24 hours that I can stick to a 24-hour schedule most of the time.
This sounds suspiciously like “I tend to stay up later and later every night unless I force myself to go to bed on time” — which I suspect is pretty common, it certainly is for me. I’ll start staying up till 3, 4, 5, or later if I’m not on a schedule. Having kids helps.
I don't think so actually. If you can "make yourself" go to bed at a "normal time" then you don't have non-24.
People with non-24 usually have a longer than 24-hour cycle and can't "make themselves" go to sleep consistently at the same time (people with 24.5 or 25-hour days probably have some success with this though because if they stay up a bit later one day and still wake up at the same time, then by the time a proper bedtime rolls around they'll be close enough to their the sleep phase of their cycle, and tired enough to fall asleep at that time)
I'm skeptical. Chronic sleep deprivation does a pretty good job of helping people go to sleep at the same time each day.
Either way, it seems like a arbitrary distinction to make. If Bob is happier and more productive on a 26 hour schedule, but can unhappily live on a 24 hour schedule, why doest that count?
It seems the relevant Factor is what their natural schedule actually is, given the circumstances etc
Why would anyone be happier on a 26-hour schedule if they can get an adequate amount of sleep and go to sleep close to the same time on 24-hour schedule?
I can see it going the other way, where if your natural rhythm is 22 hours you can likely force yourself to stay awake to align with 24 (and likely would be much happier than free-running on a 22-hour clock).
Speaking from personal experience, if I could consistently stick to a 24-hour schedule, I would. And I think most people with non-24 have the same position (and have likely tried many things before giving up, as tossing and turning for hours every night and then still not sleeping enough is pretty unpleasant).
Additionally, if Bob's rhythm is 26 hours then his sleep cycle is shifting ahead by 2 hours every night regardless of when he falls asleep. If he is able to fall asleep at the same time every night, his sleep cycle presumably isn't shifting, and even if 26 hours might be more natural for him, he's able to sync his cycle to 24 hours regardless.
So I don't think this would qualify them for non-24, as the circadian rhythm isn't shifting every day.
On the other hand, if Bob chooses to sleep 26 hours for whatever reason, perhaps he could be said to have it then? It's just inconceivable to me that someone would actually choose that given the option.
It's worth noting that the average human circadian rhythm is closer to 24.5 hours when external stimuli are removed. So it doesn't strike me as too different from Bob; people are nevertheless regulated to 24 hours by daylight and not said to be non-24, even if, like Bob, their natural state might be to sleep more.
Gotcha, that wasn't clear in your earlier comment.
If someone is unable to get adequate sleep on a 24-hour day due to their circadian rhythm misalignment then I believe this is non-24 even if it's because they wake up too early rather then go to sleep too late when trying to keep 24-hour days.
This makes me wonder about the point he briefly touches at, but otherwise leaves out: his partner. Are there no children planned at all? Have they already raised kids and are done with this? Is he planning to break up with her?
You can't do this and raise a child¹ without being, well, an asshole. He would force the mother to do all the fixed daily things, and the child to navigate your availability using your private clock.
1: After they've settled into a stable daily sleeping rhythm of course. For a baby this system might even be useful some nights (but not others).
You need a significant period of time without any time-bound obligation (or even any obligation at all). Any need for an alarm or anything that you'd possibly materialise in a calendar needs to be removed.
You need a room which is pitch black at night (e.g blocks street lights, no leds), yet still allows a tiny bit of sunlight (rationale: without cues the circadian cycle extends up to 48h, there was an experiment about that)
Then, once you have that, start freewheeling, just when you feel tired go rest and when you wake up get up. It'll be a mess at first, for two reasons.
First you may be unable to properly recognise the "I need to take some rest" signal: we're trained by life to largely ignore it.
Second, you need to pay off any debt, sleep, physical, mind, that would play a role in altering your base cycle. Have fun, work out, meditate, go see a therapist even. In a nutshell, find your balance.
Once you have recovered from everything, once all biasing sources have been removed, then sleep will converge to some rhythm, which carries some error margin, so you can only observe it statistically over time. There's your baseline.
It could take months, which more often than not isn't practical to have, so from the above ideal scenario one could devise a protocol that would try to stick as close as possible to it.
Source: first principles+anecdata, sample size of 1, double-non-blind protocol; a.k.a myself digging out of a hole.
Protocol: 3 week sick leave for burnout x anxiety depression, coincidental breakup (so no SO), went from office to remote working, workout plan, 6 month therapy, statistically reliable sleep/health/performance tracking via watch allowing for outlier identification/retrospective deviation root cause analysis.
Result: 0130-0930~30min sleep, 7h45min~5min sleep duration made of two ~4h-ish blocks, 25h~30min cycle. When bound to 24h rhythm, occasional sleepless night leading to 48h day and three aforementioned blocks of sleep (~11h-ish total).
From the data it became painfully obvious that I experience delayed sleep phase disorder, took me 6 months to figure the baseline out, and 6 more to confirm, which is quite hard when you don't even know that it is a thing.
> 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.
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)
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.
