Caffeine induces age-dependent brain complexity and criticality during sleep | Hacker News Reader

Caffeine induces age-dependent brain complexity and criticality during sleep

nature.com

58 pointsgnabgib46 comments

Basically, caffeine is bad for sleep (learning and recovery) if taken late enough and significant amounts remain in your system at bedtime. It does note that even having a coffee first thing in the morning does have a measurable effect on deep sleep brain waves. Fast metabolizers of caffeine might be different. Don't drink coffee in the afternoon is probably the take away for most people

Old people love coffee late in the day.

Grandpa used to wake up at about 2 in the morning to pee, and would have a cup of coffee before going right back to sleep.

So maybe the effects nullify after a certain point?

I've never been able to fall asleep easily. When I see someone who instantly can, I wonder if they are chronically exhausted from a lifetime of bad sleep. I know it's probably not the case but it kind of makes me jealous.

I've become a lighter sleeper as I've gotten older, but generally fall asleep pretty quickly. I don't think it's from any chronic lack of sleep. It's mostly a matter of probably lucky genetics and also actually taking my sleep hygiene really seriously which very few people do. I:

* Try to stick closely to a regular sleep schedule.

* Keep my bedroom very dark and cool.

* Don't lay in bed and stare at a screen a lot. I try to build a mental association with my bed and sleep.

* Try to get some amount of physical exercise in the day and get out of the house. I find it's much harder to fall asleep if I didn't have a full-feeling day.

* Hydrate well throughout the day, but not right before sleep. (Not as much a problem when you're younger, but as I've gotten older, my bladder increasingly is the limiting factor for sleep length.)

* Pay attention to my anxiety. If I have thoughts keeping me up, I get up and write them down. That helps my brain feel like it doesn't have to stay alert and remember them.

> * Try to get some amount of physical exercise in the day and get out of the house. I find it's much harder to fall asleep if I didn't have a full-feeling day.

This is the most improtant point that works for me. It's simple: getting a bit tired makes it easier for me to fall asleep. And if I'm not and I feel like I'd like to explore the universe when it's time to go to bed, I get on my stationary bike and my brain finally relaxes.

I wonder too.

It doesn't say so on the DT page here:

https://en.wikipedia.org/wiki/Delirium_tremens

But I read something somewhere that alcohol does something that prevents REM or soemthing, and when you stop drinking your sleep-deprived body wants to make up the REM and will even do it while you're awake.

don't know for sure

EDIT: https://pmc.ncbi.nlm.nih.gov/articles/PMC2778757/

...supports early theories that the hallucinations of DTs represent an intrusion of REM sleep processes into the waking state (for a review, see Zarcone 1978).

It's a real rarity for me to drink, it's probably been 3+ years since I've had anything with alcohol. Cannabis did help me get to sleep (though can't say for certain that it was quality sleep since it killed my dreams), but it's probably been even longer since that (I was a very, very heavy user but quit for other reasons).

That he was able to go back to sleep with caffeine in his system doesn't show anything at all about the quality of that sleep.

Any my brother seems to function having a coffee only a couple of hours before bedtime since he was 18. If I do the same I'll not sleep at all and feel terrible the entire next day.

The question is more about would you function better in some way without that, and how much effects vary over the populace.

Caffeine in low doses doesn’t really seem to have any effect for me. Or at least not an acute noticeable effect. I drink coffee out of habit and because I like it. But if I’m on holidays and don’t have access to it, it doesn’t bother me in the slightest.

I’m the same way. Drink coffee daily because I like it for breakfast. And I love espresso with dessert after dinner. When I’m away I typically consume 0 caffeine for 1-2 weeks and have no noticeable downsides. If anything I get less sleep but am more active on vacation because I’m doing more.

I suspect I’m a fast metabolizer but no way to know really.

Old people drink decaf

Have ADHD. Caffeine slows my brain down and I can fall asleep directly after having consumed a half-pot of coffee.

Same here! If I really can't sleep a small sugar-free high-caffeine energy drink is as good as a sleeping pill.

This must be my diagnosis. I can smash 3 cups of coffee and conk out in 15 minutes.

caffeine seems to accumulate though, very soon it won't matter how late in the day you took your coffee today because there is still some amount in there from yesterday too. Personally I'm trying to drink as little coffee as possible now, sleep is too precious. I cannot risk having this constant negative health impact on my life.

I am a massive caffeine drinker. Like many of us, I monitor my sleep religiously so I have an anecdote. Late afternoon espresso or hot coffee is usually quite sleep effecting.

However - I have found that cold brew does not bother my sleep! At least the brand that I drink. Very strange, but awesome. Cold brew does not have the acidity of hot coffee which is a double bonus if you get acid reflux at night from poor eating or drinking habits. Give it a whirl.

I think it will wildly vary depending on how regular your life cycle is.

As an anecdote I also tried tracking my sleep, only to realize:

- consumer trackers are wildly inaccurate (best we can do is compare them to a "medical grade" reference tracker, which might be accurate or not, who knows)

- there was so many other things going on every day, pinning it down to even two or three factors was just impossible (e.g. I drink more coffee when I have more time to make it, which is related to my stress level and work volume etc.)

- watch data were a PITA to export and analyze separately. I did it twice or thrice and didn't bother after that.

Paper suggests these changes might actually represent *worse* sleep quality. It says "increased brain entropy during sleep has been linked to hypertension and early-stage Alzheimer's disease" and question whether this represents "a deterioration of sleep quality."

As much as I like to scientifically validate my drug dependency, is the EEG work here really that much more rigorous than a polygraph? I see a lot of domain specific terms like "FOOOF algorithm", filtering signal spectra etc. and the geist of my schooling asks me whether the elephant is wiggling its trunk.

Women metabolize caffeine slower than men. Hormonal birth control slows caffeine absorption down even further.

Men can comfortably get away with afternoon espresso in a way that women simply can't.

On the bright side, they're less likely to get extreme caffeine crashes for the same reason.

I stopped consuming caffeine and alcohol years ago. My ADHD, depression, anxiety and sleep improved immensely.

I don't really miss em. The only times it's a problem is when other people try to get me to consume caffeine/alcohol because people are weird about it. I'd wager a lot of people don't really need caffeine but our society really pushes it on people. It's also a wicked cycle. Once you get to using caffeine regularly it gets very difficult to operate at the same level without it.

But yeah, regular exercise, good sleep and a decent diet make it not too bad.

Yeah, being off caffeine is amazing. What's crazy is the realization that 9/10 people you interact with are in some stage of caffeine withdrawal.

Just an anecdote, which is probably meaningless on average but: I've found that caffeine is beneficial to me and I can still gain the benefits of caffeine by drinking very little of it every second or third day. I'm talking about 1-2 sips of a cup of regular coffee. No, it doesn't wake me up like a full cup would, but it allows me to function (especially in feeling stiff in my muscles) a little better without any noticeable downside. Just an anecdote though.

> contrasting 200 mg of caffeine against a placebo condition

Burried in the middle:

> The participants reported moderate caffeine consumption, equivalent to one to three cups of coffee per day. All participants were non-smokers and free of drugs or medicine which could influence the sleep-wake cycle. Subjects also reported no sleep complaints, night work, or transmeridian travel in the 3 months before the recording.

> The participants arrived at the laboratory 6–8 h before their habitual sleep time and left 1–1.5 h after habitual wake up time. Bedtime and wake time in the laboratory were determined by averaging each participant’s sleep-wake cycle from the sleep diary. The total dose of caffeine administered was 200 mg (100 mg per capsule) which is considered to be moderate (equivalent to 1–2 cups of coffee) and induces significant changes in the sleep of young subjects23. Two-piece telescopic hard capsules were used, allowing the ingestion of caffeine without oral contamination, in a double-blind cross-over design using stratified randomization.

I doubt someone drinking 1-3 cups per day would feel that 200 mg single-shot is "normal." That's 2-3 cups in one go. For me, it would be like drinking it around 3pm.

I would fit the cohort. If I take a 200 mg caffeine capsule at 3pm, I get pretty fucked up, and I'm wondering what the self-reported effects were at the time they went to bed. Did they feel normal?

It sounds like this is one of those studies that are meant for other researchers, not the public, because the actual evidence is about effects that don't match daily lives. This type of caffine ingestion would be noticeable, and you'd pretty quickly dial it down if it was felt the way I suspect it did feel.

Did anyone see what the interval from caffeine dose to bedtime was in this experiment? I won't claim to have read every sentence, but I did skim the whole paper, read through the procedure parts, and did a couple key-word searches, but wasn't able to find that figure.

I'm stunned that the paper doesn't mention this.

I think the paper is simply "caffeine before bedtime is bad for sleep".

Especially when you consider that similar studies conclude that caffeine has an overall positive effect on brain function when consumed at 200mg per sitting and 400mg per day.

https://pubmed.ncbi.nlm.nih.gov/26677204/

100mg being equivalent to one cup of coffee or two cups of tea. I personally prefer tea as it is milder and the lower caffeine content means I can drink it all day.

Tea also has l-theanine, and that removes the jitters from consuming a lot of caffeine.

All caffeine consumption stopped at noon. It’s literally in the paper.

That's the time that the subjects stopped consuming caffeine as part of their usual diet, not the time that the pill (either 200 mg caffeine or a placebo) was administered. The subjects were required to maintain their usual caffeine intake (to prevent withdrawal), but had to stop by noon to prevent that caffeine from interfering with the experiment.

Thanks for clarifying.

The paper spends more space talking about data analysis methods than it spends talking about the protocol of collecting the data.

I think scientists judge each other too much on their statistical analysis and not enough on their experimental design.

Can somebody eli5? Coffee good or coffee bad?

DE-CA-F... good?

bad

Does anyone know what a “critical regime” is in regards to neuroscience?

I was confused when reading the abstract so I ChatGPT’d a summary and it just so happened to include this exact explanation:

1. What does a “critical regime” mean?

In neuroscience, a “critical regime” is like a sweet spot between too much order (where the brain is slow and rigid) and too much chaos (where it’s noisy and erratic). In this state:

* The brain is highly sensitive to inputs.

* It’s capable of flexible responses.

* Some researchers think this is ideal for things like learning, memory, and information processing.

BUT — that’s during waking states.

During sleep, especially NREM sleep, the brain is supposed to be less active so it can:

* Consolidate memories,

* Clear out waste (literally),

* Reset emotional balance,

* Rest and repair.

I essentially always find it more useful to do a Google Scholar search and skim a highly cited paper vs. asking an LLM.

A search for `"critical regime" brain` turns up as result #2 https://www.frontiersin.org/journals/physiology/articles/10....

> Relatively recent work has reported that networks of neurons can produce avalanches of activity whose sizes follow a power law distribution. This suggests that these networks may be operating near a critical point, poised between a phase where activity rapidly dies out and a phase where activity is amplified over time. The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point. This hypothesis, however, is still controversial. Here we will explain the concept of criticality and review the substantial objections to the criticality hypothesis raised by skeptics.

A search for `"critical regime" brain sleep` turns up a review article discussing various studies about criticality in neuroscience, including a section reviewing studies related to sleep, https://www.frontiersin.org/journals/neural-circuits/article...

Thanks for pasting that probably correct definition.

I think it just means that a sleeping brain that’s on caffeine is busier and more “complex” than one that isn’t on caffeine. It is confusing, but there’s no way that caffeine doesn’t mess up your sleep quality (for most people).

From the paper: "Maximal complexity arises in systems that achieve an optimal balance between order and randomness. According to criticality theory, this critical point characterizes the state of maximal computational efficiency and optimal information processing."

200mg caffeine is kind of a lot for me. I've dialed it down to one diluted cup (~80mg) 6 days of the week mixed with MCT, ghee, etc. I've tried bumping it to 200mg and can definitely feel slightly increased alertness late at night, even if I have it before 2pm. Gonna definitely try to have it all by noon now... since half-life is 12 hours and I sleep 10ish...

I avoid drinking coffee 12 hours before bedtime, because I read from multiple sources this is the time it takes for caffeine to be cleared from the body.

For example, if my bed time is 11pm, no coffee later than 11am.

It's been working for me so far to prevent caffeine interfering with my sleep.

Not "cleared"... 12 hours is just the half-life. Hence the minor sleep disturbance even with such a delay. However, the benefits of a healthy cup outweigh the negligible sleep brainwave issue especially if properly relaxed.

Maybe you could sweat out the caffeine.

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