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Caffeine dosing strategies to optimize alertness during sleep loss

221 points by nickcw 8y ago

baxtr 8y ago
> Caffeine, if safely administrated, is an effective countermeasure to mitigate impairment of alertness caused by sleep loss. This has been demonstrated in multiple laboratory and field studies for different sleep–wake schedules. However, to maximize its effectiveness, caffeine should be consumed at the right time and amount. Here, we developed an optimization algorithm to determine when and how much caffeine to consume so as to safely maximize alertness of a group of individuals for any situation I couldn’t find the algorithm though...
- e407 8y ago
  They built their own tabu search algorithm (section 2.3)
  - amelius 8y ago
    How large is the search space?
growlist 8y ago
Personal anecdata, I was drinking several cups of coffee to get myself through 7 hours' driving with a full work day spliced within. I used to feel absolutely dreadful. Why am I so tired despite drinking all this coffee? I used to think. I then started limiting myself to one small coffee a day. Bingo, all symptoms gone. The coffee was making me feel far worse than I would otherwise have done as it wore off, I believe.
- WhompingWindows 8y ago
  It's alertness effects go away after repeated use and subsequent tolerance building. The best way to use it is in moderation: decaf or no caffeine some days, caffeine other days when it is needed. Drinking it daily is common and often done out of liking/habit/addiction or some combination of those. However, the best positive effects will be seen with moderation.
  - eggsyntax 8y ago
    "It's alertness effects go away after repeated use and subsequent tolerance building" Link to evidence? I don't remember seeing anywhere in the literature that caffeine stops being effective when used daily and long-term, nor does it match my own experience. Thanks!
euroclydon 8y ago
Surely there’s a better drug than coffee for staying awake for a long time.
- hawkice 8y ago
  More effective, maybe. But caffeine is so widely used and understood that it is by far the safest and least risky. That's super valuable.
  - usrusr 8y ago
    "Could we get simular results without the nasty stuff if we just get the whole base on decaf during regular operations" seems to be a plausible motivation.
- tzahola 8y ago
  Amphetamine?
  - mrep 8y ago
    Yep, the classic one being adderall but you need a prescription for that unfortunately.
- tempay 8y ago
  There is though maybe not legally, for example the wide range of amphetamines. There has been a lot of research into this for fighter pilots[1]. [1] https://en.wikipedia.org/wiki/No-go_pill https://en.wikipedia.org/wiki/No-go_pill
- L_226 8y ago
  Modafinil - https://en.wikipedia.org/wiki/Modafinil https://en.wikipedia.org/wiki/Modafinil
  - gadders 8y ago
    I took some of that once for an overnight deployment at work. It's good stuff. No headaches like I would have got if I'd been drinking coffee all night.
sAbakumoff 8y ago
Is there the TLDR version of this paper?
- Bakary 8y ago
  The summary on the first page?
  - albertgoeswoof 8y ago
    I think he/she is asking for a more actionable summary. E.g. consume 10mg of caffeine every 4 hours from 6am till 2pm etc.
    - dosy 8y ago
      After 10 minute read here's what I get out of it: The study is a meta study that doesn't actually test individuals but uses data from other studies that do test individuals to assess average group performance under sleep deprivation (either total or chronic restriction) using an algorithm that tries to use the other studies as inputs and predict their results to draw out patterns by finding dosing strategies that optimize performance. The advice seems to be: reduce total caffeine amount because otherwise recovery to normal is worse, take more caffeine on days with less sleep, and less on days with more sleep, delay the dose to closer to sleep period ( otherwise your performance tanks as your approach sleep period, i.e., you only stay high for so long ), and if you can don't dose on the first and last days of your sleep restriction period, just go "natural".
    - sAbakumoff 8y ago
      exactly :-) Me(he) is asking about actionable TLDR;
- mkirklions 8y ago
  Its for people who stay up for 2 entire days at a time. Probably not useful IMO.
- ejstronge 8y ago
  Take a look at figures 5 and 6 - it's a bit hard to parse but you'll get a lot out of them. There are four different scenarios presented, and each has its own optimal strategy. In general, their optimal model uses less caffeine overall, and seems to use it in proportion to expected sleep restriction as opposed to using it widely. They cite research on the difficult in recovering from large caffeine loads as their motivation for reducing overall caffeine intake.
4ad 8y ago
I drink a lot of tea. About 1 liter a day as a baseline, but if I do some ultrahike or something I can easily drink 3 liters a day. Sometimes for some reason it's really hard to drink my tea (e.g. I'm in a hotel that doesn't have drinkable tea), so I tried to substitute with other caffeine products. Unfortunately I couldn't find out any reliable data on the caffeine content of the tea that I drink. All the information I could find is the worthless X-5X mg caffeine/cup, usually without even defining what a cup is! Does anyone know a better resource? Anyway, subjectively speaking I find that all the online estimates are too low, at least for the type of tea that I drink and in the concentration I prefer. Also, subjectively it seems that tea has a more complex psychoactive effect that either pure caffeine or coffee. If I drink enough caffeine, I can avoid the symptoms associated with caffeine withdrawal, but I don't get nowhere near as strong as an effect as I get from from tea, even if I drink a lot of caffeine. It appears tea has other stuff in it apart from caffeine. Now when I travel I take my own tea, cup, and immersion heater with me. As I said, I really like tea, but only good tea that properly prepared is good. What passes for tea these days, sometimes even in tea shops (!) is usually poison. An easy litmus test is this: do they use a thermometer when making green or white ea? If not, that means they use boiling water which will destroy the tea. I think most people never had good tea in their life. I strongly dislike coffee, but I somehow suspect I only drank bad coffee that was not prepared correctly, and that I would enjoy good coffee.
- firmgently 8y ago
  I don't know how to calculate amounts of caffeine but regarding the differing psychoactive effects, Googling 'tea stimulants' will get you lots of info... seems the main other stimulants in tea besides caffeine are theobromine (as found in cacao/chocolate) and theophylline.
- ranko 8y ago
  Can't help with the caffeine content, but I agree that there's a vast difference between good and bad tea. I particularly detest places that use a teabag and add milk before removing the bag. As George Orwell put it, "the best manner of making it is the subject of violent disputes" http://www.booksatoz.com/witsend/tea/orwell.htm http://www.booksatoz.com/witsend/tea/orwell.htm
drunkenmeister 8y ago
Is there a way we can use this algorithm for personal use?
- mkirklions 8y ago
  Do you stay up for 48 hours straight? Probably not. I think the best advice is to learn your own body. Sure there are similarities between everyone, but good caffeine habits are more important than the dosage.
amelius 8y ago
What are the inputs of the algorithm? I couldn't find it after reading the abstract and quickly scanning the first page.
_ak 8y ago
Interesting detail: look at where they authors are working. This is military research. And I'm not surprised. The problem of having to keep soldiers alert during long phases of sleep deprivation has been around since the early days of modern warfare.
- mkirklions 8y ago
  Yes, this didnt seem like it was useful for daily use. 48 hours without sleep isnt realistic for most cases, and I dont think these results have anything to say about daily caffeine. Also, I think the best advice is to learn your body. I cycle caffeine every few months. 2 cups all at once before I need 5 hours of productivity.
  - jadedhacker 8y ago
    Yea, I think the 48 hr sleep deprivation is not applicable to most people. The task also is a kind of "vigilance" task. I don't know if it applies to any kind of productive thinking. They also studied chronic sleep deprivation, maybe that would be helpful for people.
- inetsee 8y ago
  I can't find the link right now, but I remember reading a study (also funded by the military) about using sleep masks with ear plugs to improve the quality of soldier's sleep when they do have the opportunity of sleeping. Deployed soldiers frequently don't have the luxury of a regular sleep schedule. This study, combined with the other one, seems to be an effort to deal with the problems of sleep deprivation. Soldiers can get relatively good quality sleep when they can, and be alert when they must.
jillesvangurp 8y ago
Club mate is the drink of choice in the start up community in Berlin. I've made the mistake of drinking that in the evening a couple of times and regretted that at 4am by being wide awake and unproductive the next day. If you are not familiar, mate tea which this is based on contains a form of caffeine that is particularly potent. It's like drinking multiple espresso shots. Don't drink this if you have blood pressure issues. In general, I've learned to moderate my caffeine intake and restrict myself to mornings only. The more you consume, the more you need of it to work at all, and the more likely you are to have side effects like feeling tired, having poor sleep rythm, headaches, etc. When used in moderation it's a great tool for getting yourself productive after a lazy weekend on a monday morning. However, if you feel tired all the time, stop drinking coffee and get a few nights of good sleep in.
- bryanlarsen 8y ago
  "restrict myself to mornings only" Do yourself a favour and take the next step. Stop ingesting daily and reserve coffee for sleep emergencies and medicinal purposes. Even a single daily cup of coffee is enough to build a tolerance to it. Besides affecting alertness, caffeine is also a very effective way of increasing the potency of many drugs. For me, Advil by itself has little effect, but in combination with caffeine it works great.
  - awinder 8y ago
    I believe that is a factor of caffeine increasing blood flow, leading to quicker delivery within the body
    - leshow 8y ago
      My guess would've been CYP3A4, but you could be right. I found a study of caffeine producing grapefruit-like inhibitory effects on some people https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5625156/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5625156/
  - neves 8y ago
    A lot of medicines have a version with caffeine to make it more efficient and prevent sleepiness.
walkingolof 8y ago
Caffeine is also linked to panic attacks, anxiety and sleep loss (and loss of quality of sleep), I would recommend staying off caffeine all together, having tried both, I by far more like working in the calmness of not having caffeine circulating in my body. https://en.wikipedia.org/wiki/Caffeine-induced_anxiety_disorder https://en.wikipedia.org/wiki/Caffeine-induced_anxiety_disor...
- flipp3r 8y ago
  Wow, this is actually a thing! I thought it was just me. As someone who used to drink a LOT of cola-cola during their teens, caffeine really fucked me up good. I only noticed I was dependant (addicted) on caffeine after a friend pointed out I only felt good again on certain days after coming back from a client where there was no cola available. I took a little bottle with me to the client and felt "normal" that day. Didn't even know it had caffeine. Had fairly bad anxiety and panic attacks at the time. I then quit caffeine cold turkey. Couldn't even sit upright when I woke up after 2 days of not taking any. I've now tried it on and off and noticed my anxiety / panic attacks happened out of nowhere, somewhat related to consuming caffeine. I think it happens a couple hours, sometimes a day after consumptions. Really took a couple years link it to caffeine. I've been to doctors, hospitals, psychiatrists, physical therapists, blah blah blah. It was just fucking caffeine. If you read this and think consuming coffee or cola all day is fine see what happens when you stop taking it for just a couple days. Yeah I get it, you just use it to "boost" your energy during the day right, you're definitely not addicted, right? Yeah, headaches in the weekend are normal - everyone has them..
  - newfoundglory 8y ago
    I regularly stop drinking caffeine for days at a time and have been unable to notice a difference. It's a shame because I was really hoping to find that my headaches had an easy solution like not drinking caffeine, but they don't appear to be correlated.
    - taneq 8y ago
      How many days at a time? I used to drink a lot of coffee on weekdays but none on weekends and didn't notice it making any difference. Stopped drinking coffee altogether and after a few days I was really noticing the difference, and it took about two weeks for the withdrawals to wear off.
davidjhall 8y ago
there's an app, caffeine zone, that helps you find out the right time. I don't know if it based (or been updated based ) on this study. http://frankritter.com/caffeinezone/ http://frankritter.com/caffeinezone/
baldfat 8y ago
Trick: Boost your adrenaline by doing exercise before drinking down the caffeine. I learned that caffeine makes adrenaline last longer by blocking it receptors in college. https://science.howstuffworks.com/caffeine4.htm https://science.howstuffworks.com/caffeine4.htm My trick is no adrenaline no caffeine effect. I would do 10 push ups or run around my car a few times and then drink down the caffeine and that changed everything.
- hawkice 8y ago
  Isn't the half-life of adrenaline like 90 seconds? Wouldn't you be a nervous wreck if it lasted much longer?
  - Jaruzel 8y ago
    I think the parent comment is talking about the effects of adrenaline not the adrenaline dump itself. As someone who, prior to being medicated, used to get a lot of panic attacks, I can safely say that the effects of too much adrenaline being dumped all at once is pretty inhibiting.
- mkirklions 8y ago
  Will be trying this. My only note is that none of those things seem hard for someone that works out. What is the intensity for these things? I can do about 60 pushups before they start to get hard and run for 30 minutes. Do you need it to be intense? Or just do some exercise? Thanks for the tip
  - baldfat 8y ago
    Just anything that is moving your heart a tiny bit. Also old man time will take that all away from you :)
nottorp 8y ago
How about, you know, sleeping? Working in a startup isn't being parachuted behind the enemy lines where your life depends on staying alert. Go home, you'll work better tomorrow.
- awinder 8y ago
  Caffeine got me through maaany sleepless nights with my daughter for the first year or so. Sometimes in life you lose the luxury of choice in sleep ;-).
  - nottorp 8y ago
    Been there done that, kid grew up and i started sleeping again. But that's different from not sleeping because you work 16 hour days.
- Broken_Hippo 8y ago
  "Go home, you'll work better tomorrow" If only more people had this choice.
- black6 8y ago
  When I was Infantry I used a cocktail of caffeine and nicotine (usually nasal snuff, sometimes supplemented with dipping tobacco) to stay awake on extended missions. Since nicotine is a vasoconstrictor it inhibited night vision to some degree, but that was better than nodding off. Now that I'm a professional engineer and no longer in indentured servitude I stick to an 8 hour work day, get 7-8 hours of sleep a night, and have the rest of the day to spend with the family. There's no reason in this day and age to work yourself to the point of chemical dependence if your life isn't on the line.
  - noxToken 8y ago
    No nicotine for me, but I would make caffeine "dip" pouches out of the coffee packet and napkins that came with MREs. No one ever drank the coffee, so I always has multiple packets on hand. Pour the grounds into the napkin to keep it all together, then pop it in like a plug of dip. The taste was brutal, but it got the job done.
anoncoward111 8y ago
Honestly guys, my opinion in this day and age is that pretty much any substance you put into your body (including water and air) can be toxic. Some are more vital than others. We have a pretty clear need for lots of air, and a fair amount of water. But it isn't as reasonable to think that our evolution intended or makes accomodations for caffeine intake. Ingest at your own risk, whatever the dose. My wallet and my brain tell me to just go without it in my life.
- wufufufu 8y ago
  I agree with "But it isn't as reasonable to think that our evolution intended or makes accomodations for caffeine intake." However, caffeine has been tested over generations and doesn't really have any major consequences as far as I can tell. I do think that a lifestyle where caffeine makes you more effective is probably not optimally healthy, but since when does anyone care about that.
  - anoncoward111 8y ago
    I agree that all health decisions are a trade off between risks and benefits. But, in sufficient dosages, caffeine can cause heart attacks, paranoia, spasms and so on. It is a neurotoxic substance. Of course, you need to massively overdose for these things to happen. Water can be deadly if you overdose it as well. But perhaps we are missing minor damage that's occurring even with proper dosages
collyw 8y ago
Anecdotal I know but since trying to eliminate refined sugar from my diet I can manage the occasional night or two without sleep pretty well, no caffeine required.
perlpimp 8y ago
caffeine + l-theanine + picamillon. get you going steady. awake or asleep. Sleeping though is in no way replaceable. 8-9 hrs 10-6. Even fact this is mentioned here, is a bit insulting. There should be a study of how many bugs that you produce when awake but sleep deprived with/without caffeine vs well rested( no caffeine after 1pm, no food after 6pm)
- mkirklions 8y ago
  >picamillon Not legal in the US... :(
dec0dedab0de 8y ago
Anecdotally, water and sugar directly affect my alertness while using caffeine. If I don't have enough water I get headaches and can't think straight. If my blood sugar is low due to not eating enough, or eating too much sugar and "crashing" then I might as well be asleep, even though I can't from the caffeine. I may have missed it, but I don't see where they account for the diet of their test subjects.
- marpstar 8y ago
  another anecdotal story: I generally skip breakfast and lunch and do most of my eating after work. I find that the longer I fast the more I can focus, provided that I stay hydrated. I do use caffeine (almost exclusively black coffee) for alertness and appetite suppression.
  - notyourwork 8y ago
    Although I don’t fast I do avoid sugars as much as possible and only drink black coffee or tea.
  - overcast 8y ago
    I've been doing this since I was in college ~ 20 years, before the fasting craze became a thing. I just didn't really ever eat breakfast, and now I only eat between the hours of 2 - 8/10ish. I experience the same effects as you described. Increased focus / awareness. Consuming plenty of liquids is definitely required though while you do it.
  - julian37 8y ago
    IANAD (not a doctor) but just as a note of caution, I remember reading that eating one large meal a day rather than several smaller ones can have adverse consequences due to stress on the oesophageal sphincter. This study appears to come to that conclusion: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223119/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223119/ (I'm not judging, I've been known to skip the odd meal here and there myself.)
    - 8y ago
acconrad 8y ago
In case anyone found that study difficult to read, the optimal strategy was, over the course of 3 days, one 600mg dose after 12pm on days 2 and 3 of a 3 day string of sleep loss.
- themodelplumber 8y ago
  Thank you. I was thrown off because I couldn't believe I was looking at post-12pm. Those are pretty extreme circumstances. In my own case I've been tracking caffeine use and some helpful strategies are: - 30mg after a brief afternoon nap - 50mg to 60mg after a long afternoon nap that resulted in grogginess - 100mg after a terrible night's sleep and before a long meeting - Extreme care if I have an exhaustion headache due to lack of sleep and overproduction; caffeine often triggers migraine here
  - monktastic1 8y ago
    12 pm is noon not midnight, in case that's what threw you off.
    - themodelplumber 8y ago
      Of course it would. :-) Thanks! 600mg still seems crazy strong but I guess everybody's different.
      - monktastic1 8y ago
        Yeah, I feel like I'd have a heart attack well before that myself.
- vanderZwan 8y ago
  Well, that works if you know you are going to have to deal with poor sleep for three days in a row. Sadly, my sleeping problems don't have clear external factors like that so I usually don't know if I'm going to have three days of bad sleep ahead of time like that.
- 8y ago
cm2012 8y ago
A bit off topic, but if you like good coffee, /r/coffee is a great online community.
- avcdsuia 8y ago
  And if you only like drugs, /r/nootropics is a great place to discuss seriously.
ddtaylor 8y ago
My goal has been to increase protein intake and reduce my caffeine. My body and brain works better when fueled with protein. With caffeine I have to "refuel" every 30 - 60 minutes and snack on stuff but with a big protein meal I find myself not thinking of food or drink for 3 hours of hard focus.
ulisesrmzroche 8y ago
I drink about a gallon of caffeinated drinks a day, sometimes more. Am I the only one? I don't have problems sleeping, headaches, or with fatigue. I look forward to the jitters; it actually cheers me up to know that soon I'll be so intense.
- robbiep 8y ago
  ~ 25% Caucasians are fast metabolisers of caffeine so can expect to not notice much of a change with standard doses. Doesn’t mean it isn’t doing it’s thing on a biochemical level (both reuptake of intracellular adenosine and driving tolerance)
  - ulisesrmzroche 8y ago
    I was born and raised half my life in Mexico, so I probably don’t have that trait. I wonder if perhaps there’s something related though.
    - robbiep 8y ago
      23 and me will tell you for $100
- Liquix 8y ago
  Are you the only one? No. Will that habit do long term damage to your physical, emotional, mental, and professional health? Absolutely. It's so common and acceptable to be physically addicted to a stimulant (caffeine) that people tend to forget they are indeed physically addicted to a stimulant. Not saying I haven't been there in the past... but wouldn't you view your habit differently if 'I'm not alive before my second cup of coffee, hehe!' was replaced with 'I need a bump of cocaine to start my day'? I'm not implying that cocaine and caffeine are equally harmful drugs, just pointing out that physical dependence on a stimulant is NOT healthy, even if it's the norm.
- e19293001 8y ago
  Your not the only one. I drink coffee and never had sleep problems even when I drink before going to bed. I don't know why.
no_identd 8y ago
https://2b-alert-web.bhsai.org/ https://2b-alert-web.bhsai.org/ - Implementation of previous research on this by the same people, who currently work on adding this improved model to the implementation.
trendia 8y ago
Genetics play an important factor. CYP1A2, one of the enzymes that metabolizes caffeine, varies by as much as 40x between individuals. In those with a high level of the enzyme, caffeine is metabolized quickly, so they can drink coffee in the afternoon and still fall asleep. They are less likely to get anxiety from caffeine, and do not suffer from a higher risk of heart attacks with coffee consumption. In contrast, a small amount of CYPA12 prevents caffeine from being metabolized and prolongs its effects. [0] https://en.wikipedia.org/wiki/CYP1A2 https://en.wikipedia.org/wiki/CYP1A2
- simonebrunozzi 8y ago
  My dad (in Italy) drinks his last espresso after dinner, at ~9pm, every night, and soundly falls asleep by 10:30am. Perhaps he has a high level of CYP1A2? I am wondering if there's a cheap but effective method of measuring it.
  - leshow 8y ago
    I realise you said 'perhaps' but I have to comment on how much I dislike this kind of backwards reasoning. I used to compete in bodybuilding, and I heard arguments like this all the time. "I'm not making progress, I must have low testosterone", "I must not be metabolizing protein", etc. The number of possibilities is huge, you really can't say with any certainty what the cause is. Most likely he just has a tolerance to caffeine from drinking it. It sounds like he drinks it all day.
  - eggsyntax 8y ago
    May not qualify as cheap, but I believe 23andMe will tell you about the genes you've got which control your CYP1A2 levels, and predict your coffee intake accordingly.
- lithander 8y ago
  That explains a lot. I really can't relate do other coffee drinkers describing their experience. I often drink 0.4 liter of black coffee to get rid of the late evening sleepyness when I want some hours of productive free time for gaming or programming before bed. When I try to sleep ~3h later the effects of the coffee are largely gone and I fall to sleep within 5 minutes. I guess I've got a lot of that enzyme. ;) (which is nice)
pier25 8y ago
Off topic, but... Anyone knows what PDF renderer Wiley is using? The performance is fantastic. Is this PDF.js? Edit: Found it https://www.readcube.com/ https://www.readcube.com/ Edit 2: Apparently ReadCube uses PDF.js
eigenspace 8y ago
To everyone thinking about using caffine or other drugs to combat sleep: all of the latest sleep reseach would suggest that 'optimizing alertness during sleep loss' is a fool's errand if what you want is productivity. The real goal must be to ensure you get enough sleep, not that you medicate yourself with caffine to stop your body from getting sleep signals. Think about it this way: If prolonged sleep were not absolutely essential to your survival and health, sleep would be the biggest mistake evolution has ever made. an animal spending 1/3 of its life unaware of it's surroundings is an incredibly steep evolutionary price to pay. It should be obvious that if we evolved to do that, there would be gigantic benefits to it, considering htat there is not a single known animal with a nervous system that does not sleep (including insects!). If caffine was actually helpful at reducing your need to sleep, an animal would have evolved by now to endogenously produce caffine. There is a substantial body of sleep literature now showing huge benefits to physical / mental performance, willpower and creativity from sleep. Don't fight it, use it. _____________________________________________ Edit: One statistic thats particularily compelling to me: Every year during daylight savings when everyone loses an hour of sleep, the rate of heart attacks rises by 25%. On the day of the year where everyone gains an hour of sleep, heart attacks fall by 21%. Thats the effect of gaining / losing a single hour of sleep.
- abandonliberty 8y ago
  How much of sleeping is explained by metabolism reduction/calorie conservation?
  - eigenspace 8y ago
    In humans, metabolism only goes down ~35% at its very lowest point during deep sleep. In other phases of sleep, your metabolism is ~15% lower than during waking time. If sleep were for metabolic savings, it would be an incredibly inefficient way to go about it. In some senses, wakefulness may be thought of as neurotoxic and much of whats going on during sleep is centred around repairing the damage caused by being awake. For instance, the glial cells between your brain neurons shrink allowing your body to flush the beta amyloid from your brain with cerebral fluid. Beta-amyloid is a neurotoxic protein which causes Alzheimer's an is a byproduct of waking brain function. This explains the link between Alzheimer's and sleep deprivation. Sleep is also the phase where short-term memories are evaluated and either discarded or integrated into long-term memory. It's also essential for your immune health and cancer prevention. Your body produces dozens of cancer cells daily, but they're killed by your immune system. After only a single night's sleep deprivation, your amount of cancer-killing immune cells plummets. This is why shift work is now classified as carcinogenic in several countries. ____________________ Edit: Just on the topic of sleep being for energy savings, did you know that during hibernation (a state actually used for energy savings), bears will actually leave their hibernating state in order to sleep? I think that fact really showcases how important sleep is and should put to rest any notion that sleep is for energy savings.
intrasight 8y ago
I've learned, after too many years - no caffeine after 10am
maxk42 8y ago
It should be noted that all they've done here is create a computer simulation with no controlled in vitro measurements of performance. This does not necessarily predict real-world effects.

221 points by nickcw 8y ago

> Caffeine, if safely administrated, is an effective countermeasure to mitigate impairment of alertness caused by sleep loss. This has been demonstrated in multiple laboratory and field studies for different sleep–wake schedules. However, to maximize its effectiveness, caffeine should be consumed at the right time and amount. Here, we developed an optimization algorithm to determine when and how much caffeine to consume so as to safely maximize alertness of a group of individuals for any situation I couldn’t find the algorithm though...

e407 8y ago
They built their own tabu search algorithm (section 2.3)
- amelius 8y ago
  How large is the search space?

growlist 8y ago

Personal anecdata, I was drinking several cups of coffee to get myself through 7 hours' driving with a full work day spliced within. I used to feel absolutely dreadful. Why am I so tired despite drinking all this coffee? I used to think. I then started limiting myself to one small coffee a day. Bingo, all symptoms gone. The coffee was making me feel far worse than I would otherwise have done as it wore off, I believe.

WhompingWindows 8y ago
It's alertness effects go away after repeated use and subsequent tolerance building. The best way to use it is in moderation: decaf or no caffeine some days, caffeine other days when it is needed. Drinking it daily is common and often done out of liking/habit/addiction or some combination of those. However, the best positive effects will be seen with moderation.
- eggsyntax 8y ago
  "It's alertness effects go away after repeated use and subsequent tolerance building" Link to evidence? I don't remember seeing anywhere in the literature that caffeine stops being effective when used daily and long-term, nor does it match my own experience. Thanks!

euroclydon 8y ago

Surely there’s a better drug than coffee for staying awake for a long time.

hawkice 8y ago
More effective, maybe. But caffeine is so widely used and understood that it is by far the safest and least risky. That's super valuable.
- usrusr 8y ago
  "Could we get simular results without the nasty stuff if we just get the whole base on decaf during regular operations" seems to be a plausible motivation.
tzahola 8y ago
Amphetamine?
- mrep 8y ago
  Yep, the classic one being adderall but you need a prescription for that unfortunately.
tempay 8y ago
There is though maybe not legally, for example the wide range of amphetamines. There has been a lot of research into this for fighter pilots[1]. [1] https://en.wikipedia.org/wiki/No-go_pill https://en.wikipedia.org/wiki/No-go_pill
L_226 8y ago
Modafinil - https://en.wikipedia.org/wiki/Modafinil https://en.wikipedia.org/wiki/Modafinil
- gadders 8y ago
  I took some of that once for an overnight deployment at work. It's good stuff. No headaches like I would have got if I'd been drinking coffee all night.

sAbakumoff 8y ago

Is there the TLDR version of this paper?

Bakary 8y ago
The summary on the first page?
- albertgoeswoof 8y ago
  I think he/she is asking for a more actionable summary. E.g. consume 10mg of caffeine every 4 hours from 6am till 2pm etc.
  - dosy 8y ago
    After 10 minute read here's what I get out of it: The study is a meta study that doesn't actually test individuals but uses data from other studies that do test individuals to assess average group performance under sleep deprivation (either total or chronic restriction) using an algorithm that tries to use the other studies as inputs and predict their results to draw out patterns by finding dosing strategies that optimize performance. The advice seems to be: reduce total caffeine amount because otherwise recovery to normal is worse, take more caffeine on days with less sleep, and less on days with more sleep, delay the dose to closer to sleep period ( otherwise your performance tanks as your approach sleep period, i.e., you only stay high for so long ), and if you can don't dose on the first and last days of your sleep restriction period, just go "natural".
  - sAbakumoff 8y ago
    exactly :-) Me(he) is asking about actionable TLDR;
mkirklions 8y ago
Its for people who stay up for 2 entire days at a time. Probably not useful IMO.
ejstronge 8y ago
Take a look at figures 5 and 6 - it's a bit hard to parse but you'll get a lot out of them. There are four different scenarios presented, and each has its own optimal strategy. In general, their optimal model uses less caffeine overall, and seems to use it in proportion to expected sleep restriction as opposed to using it widely. They cite research on the difficult in recovering from large caffeine loads as their motivation for reducing overall caffeine intake.

4ad 8y ago

I drink a lot of tea. About 1 liter a day as a baseline, but if I do some ultrahike or something I can easily drink 3 liters a day. Sometimes for some reason it's really hard to drink my tea (e.g. I'm in a hotel that doesn't have drinkable tea), so I tried to substitute with other caffeine products. Unfortunately I couldn't find out any reliable data on the caffeine content of the tea that I drink. All the information I could find is the worthless X-5X mg caffeine/cup, usually without even defining what a cup is! Does anyone know a better resource? Anyway, subjectively speaking I find that all the online estimates are too low, at least for the type of tea that I drink and in the concentration I prefer. Also, subjectively it seems that tea has a more complex psychoactive effect that either pure caffeine or coffee. If I drink enough caffeine, I can avoid the symptoms associated with caffeine withdrawal, but I don't get nowhere near as strong as an effect as I get from from tea, even if I drink a lot of caffeine. It appears tea has other stuff in it apart from caffeine. Now when I travel I take my own tea, cup, and immersion heater with me. As I said, I really like tea, but only good tea that properly prepared is good. What passes for tea these days, sometimes even in tea shops (!) is usually poison. An easy litmus test is this: do they use a thermometer when making green or white ea? If not, that means they use boiling water which will destroy the tea. I think most people never had good tea in their life. I strongly dislike coffee, but I somehow suspect I only drank bad coffee that was not prepared correctly, and that I would enjoy good coffee.

firmgently 8y ago
I don't know how to calculate amounts of caffeine but regarding the differing psychoactive effects, Googling 'tea stimulants' will get you lots of info... seems the main other stimulants in tea besides caffeine are theobromine (as found in cacao/chocolate) and theophylline.
ranko 8y ago
Can't help with the caffeine content, but I agree that there's a vast difference between good and bad tea. I particularly detest places that use a teabag and add milk before removing the bag. As George Orwell put it, "the best manner of making it is the subject of violent disputes" http://www.booksatoz.com/witsend/tea/orwell.htm http://www.booksatoz.com/witsend/tea/orwell.htm

drunkenmeister 8y ago

Is there a way we can use this algorithm for personal use?

mkirklions 8y ago
Do you stay up for 48 hours straight? Probably not. I think the best advice is to learn your own body. Sure there are similarities between everyone, but good caffeine habits are more important than the dosage.

amelius 8y ago

What are the inputs of the algorithm? I couldn't find it after reading the abstract and quickly scanning the first page.

_ak 8y ago

Interesting detail: look at where they authors are working. This is military research. And I'm not surprised. The problem of having to keep soldiers alert during long phases of sleep deprivation has been around since the early days of modern warfare.

mkirklions 8y ago
Yes, this didnt seem like it was useful for daily use. 48 hours without sleep isnt realistic for most cases, and I dont think these results have anything to say about daily caffeine. Also, I think the best advice is to learn your body. I cycle caffeine every few months. 2 cups all at once before I need 5 hours of productivity.
- jadedhacker 8y ago
  Yea, I think the 48 hr sleep deprivation is not applicable to most people. The task also is a kind of "vigilance" task. I don't know if it applies to any kind of productive thinking. They also studied chronic sleep deprivation, maybe that would be helpful for people.
inetsee 8y ago
I can't find the link right now, but I remember reading a study (also funded by the military) about using sleep masks with ear plugs to improve the quality of soldier's sleep when they do have the opportunity of sleeping. Deployed soldiers frequently don't have the luxury of a regular sleep schedule. This study, combined with the other one, seems to be an effort to deal with the problems of sleep deprivation. Soldiers can get relatively good quality sleep when they can, and be alert when they must.

jillesvangurp 8y ago

Club mate is the drink of choice in the start up community in Berlin. I've made the mistake of drinking that in the evening a couple of times and regretted that at 4am by being wide awake and unproductive the next day. If you are not familiar, mate tea which this is based on contains a form of caffeine that is particularly potent. It's like drinking multiple espresso shots. Don't drink this if you have blood pressure issues. In general, I've learned to moderate my caffeine intake and restrict myself to mornings only. The more you consume, the more you need of it to work at all, and the more likely you are to have side effects like feeling tired, having poor sleep rythm, headaches, etc. When used in moderation it's a great tool for getting yourself productive after a lazy weekend on a monday morning. However, if you feel tired all the time, stop drinking coffee and get a few nights of good sleep in.

bryanlarsen 8y ago
"restrict myself to mornings only" Do yourself a favour and take the next step. Stop ingesting daily and reserve coffee for sleep emergencies and medicinal purposes. Even a single daily cup of coffee is enough to build a tolerance to it. Besides affecting alertness, caffeine is also a very effective way of increasing the potency of many drugs. For me, Advil by itself has little effect, but in combination with caffeine it works great.
- awinder 8y ago
  I believe that is a factor of caffeine increasing blood flow, leading to quicker delivery within the body
  - leshow 8y ago
    My guess would've been CYP3A4, but you could be right. I found a study of caffeine producing grapefruit-like inhibitory effects on some people https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5625156/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5625156/
- neves 8y ago
  A lot of medicines have a version with caffeine to make it more efficient and prevent sleepiness.

walkingolof 8y ago

Caffeine is also linked to panic attacks, anxiety and sleep loss (and loss of quality of sleep), I would recommend staying off caffeine all together, having tried both, I by far more like working in the calmness of not having caffeine circulating in my body. https://en.wikipedia.org/wiki/Caffeine-induced_anxiety_disorder https://en.wikipedia.org/wiki/Caffeine-induced_anxiety_disor...

flipp3r 8y ago
Wow, this is actually a thing! I thought it was just me. As someone who used to drink a LOT of cola-cola during their teens, caffeine really fucked me up good. I only noticed I was dependant (addicted) on caffeine after a friend pointed out I only felt good again on certain days after coming back from a client where there was no cola available. I took a little bottle with me to the client and felt "normal" that day. Didn't even know it had caffeine. Had fairly bad anxiety and panic attacks at the time. I then quit caffeine cold turkey. Couldn't even sit upright when I woke up after 2 days of not taking any. I've now tried it on and off and noticed my anxiety / panic attacks happened out of nowhere, somewhat related to consuming caffeine. I think it happens a couple hours, sometimes a day after consumptions. Really took a couple years link it to caffeine. I've been to doctors, hospitals, psychiatrists, physical therapists, blah blah blah. It was just fucking caffeine. If you read this and think consuming coffee or cola all day is fine see what happens when you stop taking it for just a couple days. Yeah I get it, you just use it to "boost" your energy during the day right, you're definitely not addicted, right? Yeah, headaches in the weekend are normal - everyone has them..
- newfoundglory 8y ago
  I regularly stop drinking caffeine for days at a time and have been unable to notice a difference. It's a shame because I was really hoping to find that my headaches had an easy solution like not drinking caffeine, but they don't appear to be correlated.
  - taneq 8y ago
    How many days at a time? I used to drink a lot of coffee on weekdays but none on weekends and didn't notice it making any difference. Stopped drinking coffee altogether and after a few days I was really noticing the difference, and it took about two weeks for the withdrawals to wear off.

davidjhall 8y ago

there's an app, caffeine zone, that helps you find out the right time. I don't know if it based (or been updated based ) on this study. http://frankritter.com/caffeinezone/ http://frankritter.com/caffeinezone/

baldfat 8y ago

Trick: Boost your adrenaline by doing exercise before drinking down the caffeine. I learned that caffeine makes adrenaline last longer by blocking it receptors in college. https://science.howstuffworks.com/caffeine4.htm https://science.howstuffworks.com/caffeine4.htm My trick is no adrenaline no caffeine effect. I would do 10 push ups or run around my car a few times and then drink down the caffeine and that changed everything.

hawkice 8y ago
Isn't the half-life of adrenaline like 90 seconds? Wouldn't you be a nervous wreck if it lasted much longer?
- Jaruzel 8y ago
  I think the parent comment is talking about the effects of adrenaline not the adrenaline dump itself. As someone who, prior to being medicated, used to get a lot of panic attacks, I can safely say that the effects of too much adrenaline being dumped all at once is pretty inhibiting.
mkirklions 8y ago
Will be trying this. My only note is that none of those things seem hard for someone that works out. What is the intensity for these things? I can do about 60 pushups before they start to get hard and run for 30 minutes. Do you need it to be intense? Or just do some exercise? Thanks for the tip
- baldfat 8y ago
  Just anything that is moving your heart a tiny bit. Also old man time will take that all away from you :)

nottorp 8y ago

How about, you know, sleeping? Working in a startup isn't being parachuted behind the enemy lines where your life depends on staying alert. Go home, you'll work better tomorrow.

awinder 8y ago
Caffeine got me through maaany sleepless nights with my daughter for the first year or so. Sometimes in life you lose the luxury of choice in sleep ;-).
- nottorp 8y ago
  Been there done that, kid grew up and i started sleeping again. But that's different from not sleeping because you work 16 hour days.
Broken_Hippo 8y ago
"Go home, you'll work better tomorrow" If only more people had this choice.
black6 8y ago
When I was Infantry I used a cocktail of caffeine and nicotine (usually nasal snuff, sometimes supplemented with dipping tobacco) to stay awake on extended missions. Since nicotine is a vasoconstrictor it inhibited night vision to some degree, but that was better than nodding off. Now that I'm a professional engineer and no longer in indentured servitude I stick to an 8 hour work day, get 7-8 hours of sleep a night, and have the rest of the day to spend with the family. There's no reason in this day and age to work yourself to the point of chemical dependence if your life isn't on the line.
- noxToken 8y ago
  No nicotine for me, but I would make caffeine "dip" pouches out of the coffee packet and napkins that came with MREs. No one ever drank the coffee, so I always has multiple packets on hand. Pour the grounds into the napkin to keep it all together, then pop it in like a plug of dip. The taste was brutal, but it got the job done.

anoncoward111 8y ago

Honestly guys, my opinion in this day and age is that pretty much any substance you put into your body (including water and air) can be toxic. Some are more vital than others. We have a pretty clear need for lots of air, and a fair amount of water. But it isn't as reasonable to think that our evolution intended or makes accomodations for caffeine intake. Ingest at your own risk, whatever the dose. My wallet and my brain tell me to just go without it in my life.

wufufufu 8y ago
I agree with "But it isn't as reasonable to think that our evolution intended or makes accomodations for caffeine intake." However, caffeine has been tested over generations and doesn't really have any major consequences as far as I can tell. I do think that a lifestyle where caffeine makes you more effective is probably not optimally healthy, but since when does anyone care about that.
- anoncoward111 8y ago
  I agree that all health decisions are a trade off between risks and benefits. But, in sufficient dosages, caffeine can cause heart attacks, paranoia, spasms and so on. It is a neurotoxic substance. Of course, you need to massively overdose for these things to happen. Water can be deadly if you overdose it as well. But perhaps we are missing minor damage that's occurring even with proper dosages

collyw 8y ago

Anecdotal I know but since trying to eliminate refined sugar from my diet I can manage the occasional night or two without sleep pretty well, no caffeine required.

perlpimp 8y ago

caffeine + l-theanine + picamillon. get you going steady. awake or asleep. Sleeping though is in no way replaceable. 8-9 hrs 10-6. Even fact this is mentioned here, is a bit insulting. There should be a study of how many bugs that you produce when awake but sleep deprived with/without caffeine vs well rested( no caffeine after 1pm, no food after 6pm)

mkirklions 8y ago
>picamillon Not legal in the US... :(

dec0dedab0de 8y ago

Anecdotally, water and sugar directly affect my alertness while using caffeine. If I don't have enough water I get headaches and can't think straight. If my blood sugar is low due to not eating enough, or eating too much sugar and "crashing" then I might as well be asleep, even though I can't from the caffeine. I may have missed it, but I don't see where they account for the diet of their test subjects.

marpstar 8y ago
another anecdotal story: I generally skip breakfast and lunch and do most of my eating after work. I find that the longer I fast the more I can focus, provided that I stay hydrated. I do use caffeine (almost exclusively black coffee) for alertness and appetite suppression.
- notyourwork 8y ago
  Although I don’t fast I do avoid sugars as much as possible and only drink black coffee or tea.
- overcast 8y ago
  I've been doing this since I was in college ~ 20 years, before the fasting craze became a thing. I just didn't really ever eat breakfast, and now I only eat between the hours of 2 - 8/10ish. I experience the same effects as you described. Increased focus / awareness. Consuming plenty of liquids is definitely required though while you do it.
- julian37 8y ago
  IANAD (not a doctor) but just as a note of caution, I remember reading that eating one large meal a day rather than several smaller ones can have adverse consequences due to stress on the oesophageal sphincter. This study appears to come to that conclusion: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223119/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223119/ (I'm not judging, I've been known to skip the odd meal here and there myself.)
  - 8y ago

acconrad 8y ago

In case anyone found that study difficult to read, the optimal strategy was, over the course of 3 days, one 600mg dose after 12pm on days 2 and 3 of a 3 day string of sleep loss.

themodelplumber 8y ago
Thank you. I was thrown off because I couldn't believe I was looking at post-12pm. Those are pretty extreme circumstances. In my own case I've been tracking caffeine use and some helpful strategies are: - 30mg after a brief afternoon nap - 50mg to 60mg after a long afternoon nap that resulted in grogginess - 100mg after a terrible night's sleep and before a long meeting - Extreme care if I have an exhaustion headache due to lack of sleep and overproduction; caffeine often triggers migraine here
- monktastic1 8y ago
  12 pm is noon not midnight, in case that's what threw you off.
  - themodelplumber 8y ago
    Of course it would. :-) Thanks! 600mg still seems crazy strong but I guess everybody's different.
    - monktastic1 8y ago
      Yeah, I feel like I'd have a heart attack well before that myself.
vanderZwan 8y ago
Well, that works if you know you are going to have to deal with poor sleep for three days in a row. Sadly, my sleeping problems don't have clear external factors like that so I usually don't know if I'm going to have three days of bad sleep ahead of time like that.
8y ago

cm2012 8y ago

A bit off topic, but if you like good coffee, /r/coffee is a great online community.

avcdsuia 8y ago
And if you only like drugs, /r/nootropics is a great place to discuss seriously.

ddtaylor 8y ago

My goal has been to increase protein intake and reduce my caffeine. My body and brain works better when fueled with protein. With caffeine I have to "refuel" every 30 - 60 minutes and snack on stuff but with a big protein meal I find myself not thinking of food or drink for 3 hours of hard focus.

ulisesrmzroche 8y ago

I drink about a gallon of caffeinated drinks a day, sometimes more. Am I the only one? I don't have problems sleeping, headaches, or with fatigue. I look forward to the jitters; it actually cheers me up to know that soon I'll be so intense.

robbiep 8y ago
~ 25% Caucasians are fast metabolisers of caffeine so can expect to not notice much of a change with standard doses. Doesn’t mean it isn’t doing it’s thing on a biochemical level (both reuptake of intracellular adenosine and driving tolerance)
- ulisesrmzroche 8y ago
  I was born and raised half my life in Mexico, so I probably don’t have that trait. I wonder if perhaps there’s something related though.
  - robbiep 8y ago
    23 and me will tell you for $100
Liquix 8y ago
Are you the only one? No. Will that habit do long term damage to your physical, emotional, mental, and professional health? Absolutely. It's so common and acceptable to be physically addicted to a stimulant (caffeine) that people tend to forget they are indeed physically addicted to a stimulant. Not saying I haven't been there in the past... but wouldn't you view your habit differently if 'I'm not alive before my second cup of coffee, hehe!' was replaced with 'I need a bump of cocaine to start my day'? I'm not implying that cocaine and caffeine are equally harmful drugs, just pointing out that physical dependence on a stimulant is NOT healthy, even if it's the norm.
e19293001 8y ago
Your not the only one. I drink coffee and never had sleep problems even when I drink before going to bed. I don't know why.

no_identd 8y ago

https://2b-alert-web.bhsai.org/ https://2b-alert-web.bhsai.org/ - Implementation of previous research on this by the same people, who currently work on adding this improved model to the implementation.

trendia 8y ago

Genetics play an important factor. CYP1A2, one of the enzymes that metabolizes caffeine, varies by as much as 40x between individuals. In those with a high level of the enzyme, caffeine is metabolized quickly, so they can drink coffee in the afternoon and still fall asleep. They are less likely to get anxiety from caffeine, and do not suffer from a higher risk of heart attacks with coffee consumption. In contrast, a small amount of CYPA12 prevents caffeine from being metabolized and prolongs its effects. [0] https://en.wikipedia.org/wiki/CYP1A2 https://en.wikipedia.org/wiki/CYP1A2

simonebrunozzi 8y ago
My dad (in Italy) drinks his last espresso after dinner, at ~9pm, every night, and soundly falls asleep by 10:30am. Perhaps he has a high level of CYP1A2? I am wondering if there's a cheap but effective method of measuring it.
- leshow 8y ago
  I realise you said 'perhaps' but I have to comment on how much I dislike this kind of backwards reasoning. I used to compete in bodybuilding, and I heard arguments like this all the time. "I'm not making progress, I must have low testosterone", "I must not be metabolizing protein", etc. The number of possibilities is huge, you really can't say with any certainty what the cause is. Most likely he just has a tolerance to caffeine from drinking it. It sounds like he drinks it all day.
- eggsyntax 8y ago
  May not qualify as cheap, but I believe 23andMe will tell you about the genes you've got which control your CYP1A2 levels, and predict your coffee intake accordingly.
lithander 8y ago
That explains a lot. I really can't relate do other coffee drinkers describing their experience. I often drink 0.4 liter of black coffee to get rid of the late evening sleepyness when I want some hours of productive free time for gaming or programming before bed. When I try to sleep ~3h later the effects of the coffee are largely gone and I fall to sleep within 5 minutes. I guess I've got a lot of that enzyme. ;) (which is nice)

pier25 8y ago

Off topic, but... Anyone knows what PDF renderer Wiley is using? The performance is fantastic. Is this PDF.js? Edit: Found it https://www.readcube.com/ https://www.readcube.com/ Edit 2: Apparently ReadCube uses PDF.js

eigenspace 8y ago

To everyone thinking about using caffine or other drugs to combat sleep: all of the latest sleep reseach would suggest that 'optimizing alertness during sleep loss' is a fool's errand if what you want is productivity. The real goal must be to ensure you get enough sleep, not that you medicate yourself with caffine to stop your body from getting sleep signals. Think about it this way: If prolonged sleep were not absolutely essential to your survival and health, sleep would be the biggest mistake evolution has ever made. an animal spending 1/3 of its life unaware of it's surroundings is an incredibly steep evolutionary price to pay. It should be obvious that if we evolved to do that, there would be gigantic benefits to it, considering htat there is not a single known animal with a nervous system that does not sleep (including insects!). If caffine was actually helpful at reducing your need to sleep, an animal would have evolved by now to endogenously produce caffine. There is a substantial body of sleep literature now showing huge benefits to physical / mental performance, willpower and creativity from sleep. Don't fight it, use it. _____________________________________________ Edit: One statistic thats particularily compelling to me: Every year during daylight savings when everyone loses an hour of sleep, the rate of heart attacks rises by 25%. On the day of the year where everyone gains an hour of sleep, heart attacks fall by 21%. Thats the effect of gaining / losing a single hour of sleep.

abandonliberty 8y ago
How much of sleeping is explained by metabolism reduction/calorie conservation?
- eigenspace 8y ago
  In humans, metabolism only goes down ~35% at its very lowest point during deep sleep. In other phases of sleep, your metabolism is ~15% lower than during waking time. If sleep were for metabolic savings, it would be an incredibly inefficient way to go about it. In some senses, wakefulness may be thought of as neurotoxic and much of whats going on during sleep is centred around repairing the damage caused by being awake. For instance, the glial cells between your brain neurons shrink allowing your body to flush the beta amyloid from your brain with cerebral fluid. Beta-amyloid is a neurotoxic protein which causes Alzheimer's an is a byproduct of waking brain function. This explains the link between Alzheimer's and sleep deprivation. Sleep is also the phase where short-term memories are evaluated and either discarded or integrated into long-term memory. It's also essential for your immune health and cancer prevention. Your body produces dozens of cancer cells daily, but they're killed by your immune system. After only a single night's sleep deprivation, your amount of cancer-killing immune cells plummets. This is why shift work is now classified as carcinogenic in several countries. ____________________ Edit: Just on the topic of sleep being for energy savings, did you know that during hibernation (a state actually used for energy savings), bears will actually leave their hibernating state in order to sleep? I think that fact really showcases how important sleep is and should put to rest any notion that sleep is for energy savings.

intrasight 8y ago

I've learned, after too many years - no caffeine after 10am

maxk42 8y ago

It should be noted that all they've done here is create a computer simulation with no controlled in vitro measurements of performance. This does not necessarily predict real-world effects.