[parkerhoyes]

I have this disorder as well, it started when I was 11 or 12. I've tried every trick that sleep doctors recommend (literally, everything) but nothing works. The only way I was able to maintain a 24-hour sleep cycle though school was to drink coffee every morning and take sleep medication regularly (from the age of 12). That was enough to make my sleep cycle 24 hours, but it didn't improve my sleep quality, so I spent most of school in a significantly sleep deprived state (only getting 3-5 hours of sleep a night). That's a pretty miserable state to live in for an extended period of time.

When I started living on my own and I was free to choose my own schedule, I decided to stop "forcing" myself onto a schedule that my body didn't agree with and instead let my sleep schedule naturally align with my circadian rhythms. It took about a month to get adjusted, but I remember waking up one morning and feeling like I had got my first full night's sleep in my entire life - it was an amazing feeling!

Since then I've been living on a ~ 24h 50m sleep cycle and I sleep like a baby (8 - 9 hrs) every night. Interestingly enough, I've discovered that I'm actually a morning person, when I used to think I was a night owl. I'm very grateful that I have the freedom to choose my own schedule (I'm a remote-only contractor), I dread ever having to go back to a 24h sleep cycle.

I haven't noticed much change in how I feel with seasons (I live in southern Ontario, Canada), but there's a big difference in my energy level depending on how much light I get in the morning (my mornings, not Earth mornings). If I don't get a good amount of bright light in the morning I feel sluggish and tired all day, regardless of how much sleep I got. If the sun's up when I wake up, I go for a run or walk every morning; otherwise I have about five 10,000 lux LED lights around my apartment that I turn on all morning (I have two right next to my desk in my peripheral vision, just like the person in the article). The LEDs are pretty weak, but they're enough if they're a few feet away from me. I start turning off all the lights and closing all the blinds in my apartment about 4 hours before bed or else it'll keep me up.

I would be very interested in reading more research about the cause of Non-24 Hour Sleep-Wake Disorder in sighted people; as far as I'm aware there's very little research on the matter. I didn't even know it existed until last year, I expect some more research and awareness could be very helpful to people in the same boat.

[rajlego]

Are you familiar with Piotr Wozniak's writings on sleep? I think you might find them interesting https://supermemo.guru/wiki/Science_of_sleep. DSPS is pretty common and fairly natural considering how we've diverged in habits from our ancestors.

[_carl_jung]

What does it mean to be on a "24h 50m" sleep cycle? Does your sleep time progressively become later until you're nocturnal, then continue looping round until it returns to a "normal" night's sleep?

[parkerhoyes]

Exactly. 24h 50m is the average I calculated after tracking my sleep for over a year. On average, the time that I wake up and go to sleep gets later by 50 minutes each day relative to a 24 hour day.

I'm currently waking up around 2am local time. In two weeks, I'll be waking up around noon.

If I lived on Mars, where the day length is 24h 37m, I would feel right at home (aside from the lack of breathable air).

[ehsanu1]

Could you please briefly explain the way you cam calculate your cycle based on average time sleeping? I have to get up using alarms at times that are not related to how my body is feeling about waking up, so I don't see how tracking that would help.

I tend to start sleep later and later until I reach some dynamic equilibrium between sleep deprivation due to fixed wake up times and the tendency to delay sleep onset.

[parkerhoyes]

I almost never use an alarm anymore - there's no need to, my body knows exactly when to wake up because of my circadian rhythms (that's the way humans were supposed to work after all - we didn't evolve to use alarm clocks). Of course, the time my body "knows" to wake up is almost an hour later than it should, and that's the whole problem.

The way I calculated the length of my circadian rhythm cycle wasn't by tracking the duration of my sleep, it was by tracking the exact time I naturally woke up every day. I then calculated the difference in the time I woke up each day (the daily "drift" in my sleep cycle). The median of those "drift" values turned out to be around 50 minutes, which means my sleep cycle is 24h 50m on average.

It might seem like not using an alarm clock would bias those measurements, but that's actually not the case. Even assuming the fact that I don't use an alarm clock makes me sleep in (it doesn't, but for the sake of argument), that would only effect the average time that I wake up every day, not the average drift in my sleep cycle. There are a number of other biases that would have to be accounted for if this was an actual study, but for my purposes that's accurate enough.

In reality, everybody has a different natural circadian rhythm cycle. If that cycle is close enough to 24h, then you'll have a "normal" sleep cycle. If it's long enough to cause insomnia / delayed sleep onset but your body can still "compensate" (that "compensation" mechanism is called entrainment in chronobiology), then that's called Delayed Sleep Phase Syndrome (I'm not a doctor, but that sounds like what you're describing). If your natural circadian rhythm cycle is so long that your body isn't capable of "compensating" to a 24h cycle, then that's called Non-24-Hour Sleep-Wake Disorder. Delayed Sleep Phase Syndrome is far more common than Non-24.

As for this point:

> I have to get up using alarms at times that are not related to how my body is feeling about waking up, so I don't see how tracking that would help.

I'm afraid tracking it didn't really help me at all - I simply tracked it because I was curious. My "solution" was simply to let my body do it's thing, but that's not an option for most people who have fixed work schedules or other commitments every day.

[ehsanu1]

Seeing this long later, but thank you for the detailed reply.