"Since then, researchers have found that in darkness most people eventually adjust to a 48-hour cycle: 36 hours of activity followed by 12 hours of sleep. The reasons are still unclear"
This statement was interesting to me. I wonder if it resonates with anyone else on HN. My BF who works from home a lot can spend days/hours at home splitting his time between working (programming) and playing video games. He has said a lot of times that the normal 24 hour cycle does not work from him. That he feels his body needs a 36 hour day followed by some hours of sleep.
After reading the aforementioned statement in the article, I wonder if it is because of he spends so much time indoors.
I did something similar for a couple years, I used to sleep 8-10 hours but only 6 times a week. People kept telling me that my rotating hours were bad for my body, but I was in perfect shape, ate well, exercised, etc. Eventually I came back to "normal" because of certain obligations and human interactions, but I think I'll return to my rotating hours once I'm done with that.
Yeah, what you described wasn't exactly a problem of yours. You seem fine with your sleeping habits. The silly point I was trying to make was that you have a sleep cycle issue parents to small kids rarely experience.
36 hours of activity sounds very long, especially as a "natural" tendency, and in the dark. I remember seeing some references to a roughly 30 hour cycle, but I can't seem to find any references. Apparently there's also been some recent studies that suggest "most" have a pretty strong circadian rhythm around 24 hours. [1] quotes some summary text from wikipedia and provides a few links.
Having grown up in the Arctic, with polar night in winter, and polar day in summer, I've always been somewhat sceptical that we supposedly can't adapt to different cycles than what is common further south. But even if I frequently shift my days by having an extended cycle, and compared to many of my friends function longer and better on less sleep, if I am active I usually get quite tired after about 20 hours. If I do stay awake through that period, I can hit 36 or even 48 hours without making much of an effort -- but I have a hard time believing that that would be a "natural" cycle (36+12) for me -- or most people.
Now, if you're forced to be physically passive, and given some other stimuli, be that books, computer games -- what have you -- I could perhaps see a longer cycle as "normal".
One alternative take on it is that being continually engrossed with what you're doing can often stave off biological needs like food and sleep.
When I was younger and would indulge in quite a lot of video games, there were nights where it would approach sunrise without feeling tired or hungry all night. Once I stopped to walk around I would feel myself get incredibly tired/hungry, but in the moment of being engrossed by an experience, it seemed to block everything out.
As for darkness specifically, I wonder how active the subjects in complete darkness were, and what kind of reduction of mental activity occurs when you are not constantly processing optical information. Both would seem to me to reduce metabolism and presumably the need for sleep to some degree.
I very quickly lose track of time when engrossed in something, especially if it's a game. Nice how that's a consistent opposite with time slowing with sensory deprivation.
I was used to a similar cycle while preparing for exams at university. It might have been less than 36h of activity, but definitely more than 24h + >10h of sleep. If not a daily job, I would be on a similar cycle now as well -- I just felt more productive and rested that way.
Btw, I'm a "night person" and I have noticed that such people are prone to long sleep times but also can sustain longer activity periods.
A little off topic, but are you a night person, or have you just never tried the alternate?
I ask because I was a self-defined 'night person' for my early and mid 20's. Once I got married and got a straight job, with early rising and what-not, I found that I'm actually a lot more functional and a lot better feeling going to sleep early (9pm) and waking up early (4am). Genuinely I am healthier and happier; it's strange.
The few times when I've been able to live with virtually no externally imposed time schedule, I found that the length of my sleep-wake cycle lengthened by about an hour every sleep-wake cycle.
This statement was interesting to me. I wonder if it resonates with anyone else on HN. My BF who works from home a lot can spend days/hours at home splitting his time between working (programming) and playing video games. He has said a lot of times that the normal 24 hour cycle does not work from him. That he feels his body needs a 36 hour day followed by some hours of sleep.
After reading the aforementioned statement in the article, I wonder if it is because of he spends so much time indoors.