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Here's the thing: never mind getting to bed, that will happen when you are tired enough.

How about sleeping through the night? A different function with different math.

My model is caffeine is well-known for having a half-life, from three to six hours depending. That means a geometric fall in effective caffeine in your system after you go to sleep (you don't continue ingesting caffeine in your sleep do you? Sleep-brewing?)

What is the function for 'tired enough'? That is, how does 'sleepiness' decline over the sleep period? Because, when the functions cross (sleepiness drops below the caffeine line) then Awake! That's often about 3AM for me.

If the sleepiness function is a different time-constant, or is more nearly linear (as I suspect, as long as you get enough cobbled-together hours of sleep you are functional which sounds like a simple unweighted sum) then inevitably sleepiness will fall faster (cross the caffeine-left-in-system curve).

At that point you can get up, knock around doing whatever, getting sleepier again. Once caffeine drops below your remaining sleepiness you can get a few more winks.

And wake up shortly after, another hour or half-hour, whatever. Repeat the rest of the night in ever-shorter cycles as your curves both approach the x-axis.

Anyway it describes my sleep behavior nearly perfectly.



And there are at least 3 different metabolic rates for caffeine, rapid, standard, and slow. As a holder of the slow gene, none of these calculators work for me since for me caffeine has a ~9 hour half life. Caffeine after about 11 am is a bad plan.


Pretty sure there's some age related effects too. Over the last ~20 years I've gone from being happily able to drink coffee after dinner, through not being able to drink it after 5pm or so, and now to having the espresso machine automatically shut off at 2:30pm - otherwise my sleep quality plummets.

I'm 57 now, I started noticing poor sleep related to late night coffee in my mid 30s. I do got fairly hard earlier in the day though, I've usually had 4 double espressos (somewhere between 17-21g of beans) by mid morning, and usually another one or two before my current self imposed 2:30pm cut off.


It's so funny but encouraging to read this. I started drinking coffee in college and could easily finish a whole pot, or have 3 Starbucks venti drip coffees in a day, but I was not sensitive to caffeine at all and could sleep right after. It also didn't seem to have that wake-up alertness effect either

Then something changed, and now I am sensitive to it like a normal person. It does wake me up after a sip or two I can feel it, and I can easily have 'too much' if I have 2-3 cups in too short of a timespan, so I've had to learn to slow down.

Having said all of this, my personal 'last call' is 6pm, with the idea that I will be able to sleep at 12-1am. But if I drink coffee after 6pm I might be delaying that bedtime a little.

It will be interesting to learn more about the effects of how much, and how long. Should I be tapering off hours before 'last call'? What is the best 'last call' time in the day and should it be earlier? I'll have to track some of this and figure this out!


My problem isn't falling asleep, it's staying asleep. Restlessness at night has become more noticeable as I've gotten older. Cutting down on caffeine, especially later in the day, seems to have helped some. I now have one cup of coffee in the morning, and a cup or two of tea in the early afternoon. This is instead of the two cups in the morning and espresso in the afternoon that I used to have before.


Everyone is different, but if you aren't already, and have the time for it, try incorporating more physical exercise into your day. That helped me deal with restlessness at night


For me personally, exercising makes me wake up multiple times at night and makes it hard to go back to sleep. I already never exercise after 6:00pm, it still happens. Any thoughts why?

Update: did a quick search, Reddit says it could be overtraining or dehydration.


You might try slow release melatonin. I've found melatonin increases the vividness of dreaming, though.


Or reduce the dosage. I've had much better sleep on 1mg than the 3+ mg you find most places.


1mg should really be the max dosage that is available. Most people should take 0.3mg.

https://www.lesswrong.com/posts/E4cKD9iTWHaE7f3AJ/melatonin-...


Yeah it's well known that liver enzyme efficiency declines slightly with age. Also you may unknowingly run into medications that inhibit it, which gets more likely as you age and accumulate chronic issues requiring medication.

I'm envious of your 100 grams of beans a day consumption - if I have more than about 10g / one single espresso I'm a wreck for the entire day! The area-under-curve for slow metabolizers is 9 times larger - 3x the duration, 3x the concentration.


Given caffeine has a half life in the body, couldn’t you have less coffee but drink it for longer in the day and have the same result?


Honestly, I've noticed how sensitive I am to caffeine when I have reduced my caffeine intake. I think that it is important to clean the body before starting to observe, understand, and make conclusions about how a particular thing affects the body. Let it be caffeine, alcohol, or anything else.


Caffeine metabolism becomes less effective as you age


This is interesting.

One thing I am fairly sure about, the amount of caffeine makes a difference to my sleep quality. If I have a single cup of coffee in the morning, no more, then my sleep quality seems not to be impacted. If I have several cups of coffee, only in the morning, I feel great for the morning, very stimulated, but my sleep is impacted. I wake up with a buzzing several times a night and have never been able to understand what is causing the buzzing.


>have never been able to understand what is causing the buzzing

Most likely it's the leftover caffeine still in your system that's beyond your personal threshold for quality sleep.

I have the same issue. If I drink two double espressos very early in the morning and then no more after that for the rest of the day, I have no problem falling asleep at night but I keep waking up several times during the night with a buzz, while my gf can drink 3 coffees per day and an espresso after dinner and still sleep.

The only way to get rid of this is reduce my caffeine intake to absolute zero, which is hard when you get the smell and taste of fresh single origin beans. I guess some people are just that much more sensitive to it than others, genetics be dammed. I wish there was a cheap way to measure the caffeine content in the coffees I make so I can precisely determine my personal threshold.


> have no problem falling asleep at night but I keep waking up several times during the night with a buzz.

Yes, that's me. I can fall asleep, but I wake up a lot.


Try drinking more water. When I drink a lot of water, I feel that I can drink a cup much later in the evening and sleep much better at night. I highly suspect that the water intake and release washes caffeine away with it (e.g. helps with whatever mechanism caffeine is removed be it filtration, chemical, metabolism, etc). There are lots of other benefits to remaining well-hydrated, I wish that I understood this decades ago.


Just curious, but how do you know that you are a "holder of the slow gene"?


a) personal experience, also my mom carries it. b) I had my exome sequenced in 2018, and Promethease generated a report from it that showed slow metabolizer in cyp1a2


Probably though 23andMe and the CYP450 enzyme CYP1A2.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212886/


Actually went through fullgenomes.com - they apparently don't offer exome sequencing any more but for under $1200 getting your genome sequenced is interesting.

If you ask anyone who works in genetics, though, they'll advise you never to do it. It can be bad news, but there's virtually no good news there.


It's useful to have as a resource that you can dip into; for instance to check a specific thing like "how fast do I metabolise caffeine (bad example as youc can get that from a SNV checking service like 23&Me. However, never ever EVER dump your whole genome into a program that will output every match for some potential condition. Now that's not for the reason you might immediately think ("Oh no look at all the bad stuff"), but rather because the databases that tools like this use are pretty chock full of junk where some researcher threw in a reference - along with a few thousand others - to say that their particular piece of research implicates this gene at this poistion with this variant. I've seen it with my own eyes, and a lot of it is very low quality. You therefore need highly curated databases where the genotype-phenotype associations are well-defined and thoroughly researched. You'll spend the rest of your life either trying to prove/disprove every potential false positive, or just worrying yourself needlessly. So, yeah, it's not a bad resource to have if you can be responsible with it.


Hmm, now I'm interested in seeing if an LLM could be finetuned to give an effective quality score on such a study.


I had mine run twice through 23andMe just to make sure they didn’t get something wrong. I tried to get my full genome once but the company screwed me over.

And I take exception to your “no good news”.

I discovered a gene polymorphism that led to the discovery the reason for my immune deficiency and mood disorder.

I found it gave me agency as well since I know that these genes are all risk genes and not fully determinant genes.


It's funny because your post in another thread is one of the reasons I brought it up here.

I would regard that as one of the exceptions in the "virtually no" caveat.


Nowadays whole genome sequencing can be done for $300-400 (for 30x WGS, with 100x around $1000?), it's been on my TODO list for a few years.


Mm, there is more than one function fwiw you're looking at. Biological processes are complicated.

You may enjoy https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541543/ which explains more than I can




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