Epistemic status: moderately confident that something like this is directionally true, but good data or arguments could change my mind. Note the lack of citations — this is based on memory.
Most rationalists I meet believe the following:
- Sleep is very important
- To get the best sleep, install blackout curtains strong enough to prevent any sunlight from coming in in the morning
I disagree with them. I believe point 2 is false for most people, and that natural light in the morning is helpful.
In my model of the world:
- Your circadian rhythm figures out what time of day it is based on the amount of blue light hitting your pupils, and picks a time it thinks you should wake up
- It’s important to wake up at a consistent time each day, so your circadian rhythm is your friend
By blocking out all light in the morning, you might get a short term increase in the number of hours you sleep, but I predict you will hurt your sleeping consistency (and potentially soon you will start staying up later, negating your benefits entirely).
If you are the sort of person whose body wants to wake up 3 hours after sunrise, let your body have a little bit of natural light to let it know that sunrise is coming. If you’re the sort of person who's body wants to wake up with sunrise, I predict you’ll do best by waking up with sunrise.
My advice is to take the energy you were going to spend on blackout curtains, and instead spend it on smart lighting that automatically gets redder in the evening.
Exception: if your circadian rhythm is incompatible with the schedules of other people, you may want to black out your windows and use artificial lighting to simulate a later sunrise. For example, you may work in the UK, have coworkers in California, but be a morning lark.
I have "whiteout blinds". White woven roller blinds. Their primary function is privacy. They let in enough light, both straight through and round the edges, that when it's day outside, it's day inside. When it isn't winter, I also leave a window open slightly for ventilation.
I've never understood the obsession with going to bed and getting up at fixed times, independent of the seasons and everything else. (Is it a general American thing? I don't hear about it in the UK.) I trust my body to tell me when it's tired and when it's wakeful, and act accordingly. However long or short I sleep, that must be the sleep I needed.
It's a you-have-to-commute-to-work thing. If you're expected in the office by a particular time (i.e. for morning stand-up), then you need to leave at a particular time. This implies you need to wake up at a particular time, so you can brush your teeth, shower, get dressed, etc.
If I trust my body to tell me when it's tired, I'll work all night until about 8-9am, and then go to sleep.
Are there things you do to get your body's natural sense to actually match up to reality? Turning down the lights or altering the temperature?
My body literally doesn't send sleep signals. It might send vague fatigue signals at some points, but without actual effort, I would literally stay up all night, every night.
The only exception is on days when I'm already very sleep deprived. Say I slept 2 hours and then worked a 10 hour day. That night, I'll fall asleep at 9-10 without any effort, but that's the rare exception.
No, nothing of that sort.
My sleep is very irregular, though. I keep records of this and various other things, and over the last seven years the average is 6.5 hours and the standard deviation 1.4. Not a problem, because my work has rarely required fixed hours, nor has my social life involved partying through the night. I only use an alarm when I have something like a train to catch.
I do not get SAD, and my daily cycle is not affected by the clocks changing, nor by travelling a time zone or two east or west.
My sleep recently became reliably better after getting a sleep mask (which seems like it should be "the ultimate blackout curtain.")
Previously, I was the sort of person who's body tends to wake up at sunrise... and also definitely the sort of person who's body wants to fall asleep ~2am. I tried altering my sleep schedule a bunch, but it didn't improve much at all until a) about 5 years ago when I finally got a job that just let me wake up at 10am, such that going to bed at 2am was reasonable, and then b) 3 years ago, when I got complete blackout curtains, and then more recently got a sleep mask after moving to a house where blackout curtains were impractical.
I probably agree with "you actually need to get up at the same time every day", but, showing up for a day-job seems like it should automatically do that?
I basically probably endorse this for you, but would also suggest whether you could do more automatic red-shifting and dimming of your lights in the evening.
Complete blackout curtains coupled with a dawn simulator seem like a great idea if you live in a place where the length of the day varies greatly throughout the year. That's what I plan on doing.
I installed a couple of LED cornbulbs, which make my room about half as bright as full sunlight. Then I recently bought a couple of wifi-based lightbulbs, which connect to my smartphone and allow me to turn them on one at a time 1 hour and 30 minutes before my alarm goes off. This is far better than a normal light-based alarm because it is bright enough to actually influence your wakefulness (and doesn't increase the footprint of items in your room). The major problem is that my partner, like all right-thinking people, hates my LED cornbulbs. We've had a long-distance relationship for the last two years, but will be moving in together in the fall, and I anticipate I will have to give up on my beloved engineered bedroom at that time.
Is that common? My model was that people vary mostly in how much morning light affects them, where at 100% it's "wake up soon after it gets light" and at 0% it's "sleep until you're done sleeping regardless of light"? And in between you have things like "if it's light when you mildly rouse from your second-to-last sleep cycle you have a large chance of fully rousing, and so get less sleep in expectation".
Given how much outside light varies over the course of the year (sunrise at 5am in June, 7am in December), if you benefit from a visual indication of wake time blacking out the external light and replacing it with light under your control seems much better, if you can get it bright enough?
My model was that this is the thing going on for many night owls. I believe I had studies at one point that would back this up, but could not immediately find them.
I'm not in principle opposed. The approach you mention has super conceptual benefits under the model you and I share. In practice, I find my friends often have lights that go from zero to very bright very fast. I expect this to be more equivalent to an alarm clock than a subtle nudge to your sleep cycle mechanism to start moving towards wake-up-land.
If you want to have a consistent time of going to bed, that means you have to choose the time you go to bed based on when events that you might go to like birthday parties or other evening events end. For many people in summer, that time of going to bed conflicts with waking up shortly after sunrise.
On the other hand, your work also sets a boundary of when you have to get up, so for most people, there's a preference to have control about when they go to bed and when they wake up.
Blackout curtains allow you to manage the amount of blue light you get yourself. It's easy to have Hue lights that give you some blue light before you wake up and have curtains open automatically when it's time to get up.