One anecdote you keep hearing about some very advanced practitioners is that they sleep less, with no apparent ill effects. Perhaps that's worth investigating.

I have noticed this. Meditation slowly seeps outside of the time you devote to it and it colors everyday existence. I first started noticing in my twenties that I could spend an entire night awake, in bed, even sometimes out of it, and not feel deprived in the morning. It's not something I can do every day, and stress has an effect, and my activities are very constrained, bright light wrecks it so I can't use computers or phones. But when the factors all line up, nighttime becomes my favorite part of the day. :-)

People on a Ketogenic diet report need only 6 hours of sleep with no adverse effects. I am on Keto plus I also meditate, and I currently sleep 4-5 hours a night, but I'm feeling awake and refreshed. This is both awesome as I used to be an owl, and it freaks me the hell out. This is completely unreal, and I wonder if its going to last or if it is just the usual temporary keto insomnia due to disrupted melatonin synthesis. It needs glucose and takes a while to adapt (Glucose -> L-Tryptophan -> Serotonin -> Melatonin).

Anecdotally, I experience the same thing when I'm on keto. I have much more energy during the day and I'm not groggy in the morning. Otherwise, it's nearly impossible for me to wake up even if I've had 8+ hours of sleep, and I often sleep through my alarm.

I'm more of a low carb person rather than keto, but I can anecdotally confirm that how many carbs and/or sugar I have the day before does impact my alertness the next day regardless of sleep.

I also do time restricted feeding and skip breakfast. If I load up on carbs (particularly crappy ones) the day before, I feel hunger much more the next morning than if I ate clean during my feeding window.

The body is a complex machine.

I haven't noticed this on keto, though I wonder if that has something to with my nighttime eating habit.

I do notice that I need substantially less sleep when fasting. Sometimes I only sleep 4 hours a night when fasting.

The article mentions its difficult to find people that can sleep with an EEG cap inside a loud MRI machine. I'd assume the same would be true for meditation as well.

One has to wonder how that affects the validity of sleep studies, or at least their applicability to the general population.

it would seem likely that if they discover a physical mechanism at work in select individuals brains (electric waves followed by rhythmic waves of fluid) that the mechanism exists in some form in all individuals. I agree it does make for a clear follow up question: "could this mechanism be altered in some ways in people who experience sleep problems?"

Or even "could this mechanism work differently in people who are unusually easy sleepers / deep sleepers vs. the general population?"

This was not true in my case. I cannot meditate easily if I hear conversations or erratic noises, but the steady rhythmic nature of the MRI machine integrated effortlessly with my meditation. The staff thought I was sleeping, and said they'd never seen someone sleep through such noise.

For me it is fairly straight forward to meditate even in noisy environments where I could not sleep. But I have no idea how prevalent that is. Certainly many people meditate in dark and quiet spaces (I worry I would fall asleep in such spaces but again, that's just me)

Yes, there are many noisy environments where it is easier for me to meditate than to sleep, and some in which the reverse is true.

I had that thought too. Perhaps it’s more effective?