Why thinking hard makes us feel tired | Hacker News Reader

Why thinking hard makes us feel tired

nature.com

334 pointsrntn189 comments

See this is why I get annoyed at a body evolved for caloric scarcity. We shouldn't get tired, we should get hungry! Oh, pollutants build up in the brain? Burn more energy to get rid of them! I should be able to strap an icepack to my head, fill a bottle with olive oil, and overclock my brain to 10x speed.

Hahaha that would be nice. But it likely demands a stock of varied nutrients, not just "energy". Also the cells changing need to take a break to consolidate what they have adapted to (brain plasticity).

> Also the cells changing need to take a break to consolidate what they have adapted to (brain plasticity).

I feel like this has got to be a problem solvable by throwing money at it. Not as is, most likely, but if we had evolved without caloric restriction there would be some kind of more complicated support structure which handles all that.

This feels like it may fall into the realm of "I think if we just throw money at it we could solve it" problems that you can't actually solve by throwing money at.

Metaphorical money thrown at evolution several million years ago, namely calories. You were built on a budget, just because it's still better than anything we could make doesn't mean it's the best evolution can do under lesser constraints

If we had no calorie restriction why would we have evolved.

underrated perspective

Something else would end up scarcer

In an energy-rich environment, evolution should select for faster and faster reproductive rates.

Perhaps so, but humans are reproducing later and having fewer offspring, so there are more variables than just energy.

Environmental stresses are well-known to cause reproduction rates to plummet. That can be because of a lack of available food, but it can really be any sort of stress.

That's true, we evolved to adapt to calorie scarcity but our environment has changed: calories are now abundant but our system is still optimized for scarcity despite that constraint no longer existing. I'm sure in a few thousand years that'll go away (possibly faster, as we get better at manipulating our own biology) but the status quo is that we're poorly adapted to our environments, energy-wise.

Excellent point.

But note that calories scarcity is a simplistic model.

What I'm trying to show with what I was saying, is that there are stocks of scarce molecules imposing performance limits too.

If we had evolved without caloric restriction in an "easy" energy-rich environment where there's less competition for scarce energy and thus complexity and intelligence aren't absolutely mandatory to acquire it, evolution should select for faster reproductive rates by simply sacrificing complexity, not building some kind of more complicated support structure.

Well yeah, obviously. It's just a dream after all

> See this is why I get annoyed at a body evolved for caloric scarcity. We shouldn't get tired, we should get hungry! Oh, pollutants build up in the brain? Burn more energy to get rid of them! I should be able to strap an icepack to my head

Well, you did identify the major problem with the unlimited overclocking plan. Burning more energy generates more heat. An icepack on the side of your head doesn't solve the problem; at some point your brain (and the rest of the inside of your head) will cook, which is fatal.

Imagining that we evolve cooling fins on our head for better heat dissipation. We already have the fluid circulation system after all.

Many of us have evolved a lack of hair on our heads, that's a first step right?

And the rest of us are capable of removing our hair (at least temporarily).

"Did you shave your head?" "Yeah, I have a big math exam coming up, so you know, I'm pulling out all the stops"

The scrotum can rise or fall based on the need for cooling. Can we concoct the genes that would allow our heads+brains to do the same ?

no, please. i don't want scrotum head

Sweating, especially on our head, is an adaptation like that that many mammals do not have but we do.

>Burning more energy generates more heat. An icepack on the side of your head doesn't solve the problem; at some point your brain (and the rest of the inside of your head) will cook, which is fatal.

I think they sell a fancy cooling device using water cooling on NewEgg that solves that problem. It has some wild lights though.

I don't think energy is the limiting factor here. A better analogy would be with the limits of computability. Garbage collection tasks are postposed to when we're asleep, but they can only be put off for so long and there's a capacity for "stuff to consolidate later" that fills up.

Something that you probably could get is a nob to control the adaptability/efficiency setting on your brain. At the cast of learning/remembering nothing, you could "execute" for longer. We know that real brains make this trade off, but the transition from one mode to the other is slow because it's reactive.

> Garbage collection tasks are postposed to when we're asleep, but they can only be put off for so long and there's a capacity for "stuff to consolidate later" that fills up

Do we have a strong reason to believe that? I know brain and sleep mechanisms are tricky topics with lots of unknowns, but I thought I had read research that showed sleeping brains likely perform a chemical analogue to "garbage collection".

Indeed, it's called the glymphatic system. We evolved to have a circadian system that drains brain waste products during sleep. There are probably other unknown neurological consequences of sleep that remain to be detailed.

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

https://www.nature.com/articles/s41467-020-18115-2

It's not just us, as in humans. (Not saying you said otherwise.) Practically all animals sleep, even invertebrates like octopuses.

Even spiders do: https://www.cbsnews.com/news/spiders-may-sleep-and-dream-lik....

It's unlikely for sleep to only do one thing. At a minimum it reduces caloric expenditures and accumulation of damage or risk through activity. It also allows time to heal injuries without the need for inflammation to immobilize the area.

Really lack of movement is probably useful and harmful for all kinds of things. REM sleep probably has some brain benefits but moving the eyes may relate to circulating fluid within the eye etc etc.

Microsleep is a GC pause.

In addition to the chemical ones others discussed, there is informational "garbage collection" as well. There are a bunch of motor tasks that only show certain types improvement after sleep - not time, sleep. There are also rodent studies where you can do a learning task and then "clear" part of their hippocampus using optogenetics. If you clear it before sleep, they forget what they "learned" if you clear it after sleep they still remember it. Again, multiple clever conditions to control for time and separate it from sleep.

Dolphins are better adapted to this as they can turn off half their brain (and vice versa) while still functioning and alert for up to 15 days straight.

Would be interesting if one day we could induce or evolve to have similar capabilities.

https://www.smithsonianmag.com/smart-news/dolphins-sleep-wit...

I hope our environment doesn’t become so adverse that we need to evolve that capability but little do we know about the human of the future, whether it will even be our ancestor or a complete different species.

The human of the future will likely be a computer.

That makes as much sense as saying that they'll be a "steam engine."

Nice, Glutamate Garbage Collection.

It would frankly shock me if there wasn't some pricey but extant way to handle garbage collection more quickly. It would be laughably stupid to implement in a caloric desert, but I can't imagine there isn't some way to do time-sharing or a larger support network.

Only semi related, but i wanted to install a USB jack in my belly button so i could charge my phone off my visceral fat, which seemed like a win-win. Probably best I didn't, though, because this predated usb-c...

Good point, but given there are neurons in the belly, would you be unable to process emotions or be in a really fancy mood after charging your phone?

Lol, more practically you could get something like this!

https://www.amazon.com/Zeus-Dynamo-Powerhouse-Crank-Generato...

Or, if you live in a cold climate, you could make a thermo-electric generator vest to wear around town.

Is there any ongoing development of implants to "burn" fat in-place, converting it to something more readily metabolized ? (glucose?)

You basically can do that. One of the limiting factors is your ability to metabolise energy sources into energy your body can use. Improve that by increasing your fitness and your cognitive ability will be improved as well.

> Burn more energy to get rid of them! I should be able to strap an icepack to my head, fill a bottle with olive oil, and overclock my brain to 10x speed.

Stimulants like methamphetamine do that don't they? I mean with other negative side-effects, of course, you'll feel like your brain is working 10x the speed.

Tough to get a stable overclock that way though.

Only because more 'feels' better, so you take more. And then, more still 'feels' better. If you only stick to doses you can't feel, it's long term reliable IMHE.

You might feel like you're doing 10x the work but it won't be 10x work

Haha fair

Or ... be smart about being smart!

Choose what problems you work on wisely. Make sure when you are getting paid, you are getting paid for familiar work (less tiring for the brain) and then use up your smart reserves on your side project, or for your friends/family or community or society.

One option is to be like an Electron app, throw more RAM at it and be busy, the other is to be like a native optimized app - get the same stuff achieved with less resources.

-O-

To address your burn more energy to get rid of pollutants. I wonder if a 20 minute nap has the same effect. It is the CPU equivalent of letting the overclocked CPU cool down. Rather than throwing energy at the problem (which means more work and chemical processing for a biological creature), just let the body run it's natural defrag cycle.

This is why I like this forum: Understanding brain biology with a Electron's app RAM consumption analogy.

Had the same thought. This really is the better Reddit for nerds.

no wonder this place is dying

Yeah, but after you've done all that, you still have room that you could do better with overclocking yourself.

Or...I could do all those things 10x faster and better by burning 10,000 calories a day, breathing pure oxygen, redirecting bloodflow to my brain (necessitating sitting in a chair), and running a 50 watt cooling system at all times. That's not necessarily the Electron app style, if you're already doing the best you can do your only option is MOAR POWER

> we should get hungry

Personally, it does! Working hard makes me hungry, also tired, but less so if I eat well. I obviously can't overclock my brain as you describe, but there is definitely a link.

Speaking of overclocking, that's what bats do. Flight takes up a lot of energy, so they have evolved systems to deal with all the byproducts, including toxic chemicals. Interestingly, this is also why they have no problem carrying what for us are deadly viruses: overclocking results in cell damage, something that bats are equipped to deal with, but it would also trigger inflammation, so bats have damped their inflammation response, but that would leave them vulnerable to infection, so they evolved a faster immune response that is able to outpace the virus, and when one of these viruses jump to humans, they have time to reproduce a lot before our immune system reacts causing a massive inflammation that ends up doing more damage than the virus itself.

I wonder if bats get a lot of allergy problems

They get deadly nose infections by fungi... Not a great trade.

I get sleepy when I eat

I once had the same problem. That usually means unhealthy diet and constant eating and lack of exercise that all result in huge insulin spikes and insulin resistance.

Try 16/8 intermittent fasting and a healthier, more balanced diet and walking for a few minutes after meals and you will feel like a new person. After meals you will feel energized and awake.

Just a note that there are common conditions like postprandial hypotension[1] (or various other types of hypotension) where what you want is more, smaller meals.

The way a doctor explained it to me is blood rushes to the digestive system after we eat and, while normally bodies compensate for that via increased blood pressure (vasoconstriction and heart rate increase), for some people that process doesn't work well and they get a blood pressure drop instead.

[1] https://academic.oup.com/biomedgerontology/article/60/10/126...

Good point. To me it doesn't really matter if I do 2 large meals or 5 small ones. With the "constant eating" I meant the duration and not the frequency.

I feel sleepy after meals, but if I go for a brisk walk not long after the meal, I start to feel extremely faint.

I eat well and do 16/8. By eat well, an example is a heavy salad, arugula, roast chicken, tomatoes, a bit of cheese, mushrooms, and croutons, light dressing. That's a lunch at 1p. By 2pm, I'm ready to slide under my desk for a nap.

A slightly different view - when I was doing psychedelic mushrooms few times long time ago, the whole experience feels like serious overclocking my brain. Not only expanding it breadth of perception many times (aka expanded consciousness), but also the unrelenting intensity at highest revs of all of it.

When coming down from the trip (which can take easily 2 hours itself), its always super pleasant and feels very meditative, and at the very end, massive exhaustion sets on. I mean mental exhaustion I luckily can't get to via any other way, even if I pull an intense all-nighter that's nothing compared to it.

Massive headache, feeling of burning out from inside, using every calorie available in bloodstream. Its the only headache for me on which normal weak freely available painkillers (paracetamol and ibuprofen-based) are not enough.

For whatever reason, hunger nor thirst never enters the picture, those emotions are completely blocked up there.

Guy at work used to put his hand over people's head to see if they were solving a problem or just staring at code. He was always able to tell. I prefer a kilo of cashews to a bottle of olive oil, but you can totally train your metabolism to utilize the fat. Some antioxidants from peppers or leaves into the mix and my brain doesn't get tired until its time to do some dreaming to unclog the stuck bad ideas.

You can overclock it with Modafinil.

So the way to fight mental fatigue is to make sure you get rid of those pollutants, or make sure they don't build up so fast.

To get rid of pollutants, your body needs to drain them away through your vessels. For this system to work optimal, you should regularly exercise and avoid cholesterol-rich or inflammatory food that clogs your arteries. What could possibly also help is move around a bit to avoid overly tensed neck muscles.

>Oh, pollutants build up in the brain?

Perfect time to write some code to let it out. :d

I don't know which is more tiresome, 3-4 hours of focused programming and thinking, or 8 hours attending two children below 5.

They are both tiring, but differently. Intensive programming is like working hard at the gym. Tiring, but content. Attending children is low intensity in attention, but constantly vigilant. And you are expected to pay that kind of attention for another maybe 4 years. Very different kind of tiring indeed, both makes you unable to focus afterwards. So while thinking hard makes us tired, not thinking hard can also makes us tired.

It really is the vigilance. It's hard to explain to people who haven't experienced it. I certainly tried to understand my colleagues who had kids, but it turns out it's quite a bit harder than the hardest I imagined. Nowadays I'm a part time developer, and the rest of the time, I'm the primary care for a toddler.

Programming at work is my time off.

You have to be react so quickly to certain things that it keeps you totally wound up. You see them pick something up off the ground and wonder, 'what is that, are they going to eat it' and instinctively you sprint half way across the room to grab what turned out to be a cheerio from their mouth. It's almost always a cheerio. But your brain won't let you rest if there's even an impossibly small chance it's a battery or I dunno, glass or whatever, it doesn't matter how many times you check, you can always imagine something. It's exhausting.

I'm rambling because I'm tired. :)

I feel you completely. The children brought me joy that no way I can express how grateful I am. They made me realized experience can only be, well, experienced. No amount of describing can imprint the experience onto anyone. Now I empathize much more with co-workers when they seem oblivious to some solutions. Right now the children are asleep. I tried to catch up some articles or to prototype some something. But hey, no more focus juice left at all :)

You'd think nap times would help, but due to a combination of being zonked from the morning shift, and the mild anxiety that you need to take advantage of this nap time to relax, you end up just staring at a figurative wall for 2 hours.

I agree about the joy. This child woke me up.

Protip: store your cheerios in the box they come in rather than on the floor to disambiguate this scenario.

Heh, somehow once you have kids, keeping all the cheerios in the box becomes very challenging.

- When I had the first kid, when they would drop a cheerio on the floor, I would pick it up. - When I had the second kid, when they would drop a cheerio on the floor, I would leave it there. - After the third kid, I would just open the box of cheerios and dump it on the floor.

Tell me you don’t have kids without telling me you don’t have kids. :)

Hehe. Brilliant.

Tangential story, early-teen equivalent of floor-cheerios:

My daughter currently has braces and is at the stage where she needs those elastics (tiny rubber band thingies) on either side of her mouth, which she needs to take out before eating and put back in after eating.

I've started taking photos of the various places in the house that we've found these rogue elastics as they have a habit of 'pling'-ing off into the ether during removal or replacement, and they're freaking impossible to track mid-flight by the naked eye (mine at least).

Hallway outside the study, just inside the laundry door, on the footstool, on the coffee table, on the kitchen bench... Nothing particularly funny in and of itself, but I'm hoping the volume and regularity of discovery makes it funny.

Yes, that's funny. How's the early teenage years going? I kind of worry about that time..

If you've put in the hard yards leading up to it, it will be much easier. We don't really have much trouble from either of our two, but they're early into their teens (13 ands 15). Talk to them at a higher level than you think they're at and they'll pick up what you mean if not by the actual words, then by the tone and body language and all those other factors we, as adults, pay zero attention to. And make sure to explain things, take the time. Explain your choices, explain why they have to go to sleep, why they can't just eat dessert forever, why mummy and/or daddy have to leave them for the majority of sunlight hours five days a week. They understand more than you think they can, and they're always learning from literally everything that you do when you're around them.

I'm actually not looking forward to the later teen years for a couple of reasons:

- Girl/Boy-friends and associated emotional messiness

- Their moving out - Empty nest syndrome. I moved out at 18, which is only 3 years away for my eldest.

The 15-year old has always been good at pointing out flaws in our logic when either trying to discipline him or get him to do things he doesn't want to do, and we choose to persist with answering his talk-back to a certain point, but after that it's "do it or else". He's generally compliant, but will let us know if he thinks we've done him an injustice. And I'm fine with that. Don't roll over, but know when you're beaten. He plays computer games too much, but is still getting "good enough" grades and playing two sports, so it's difficult to justify coming down too hard on him for the (unbelievable to the parent version of me) amount of time he 'wastes' gaming. Little version of my pre-parent self. I suppose the gaming keeps him out of other troubles. He also put his PC together himself and has a frankensteined mechanical keyboard with replaced switches and keycaps. Sigh (that's a sigh of jealousy for the time he has to pursue these things).

The 13-year old is the most beautiful human I've ever met. She's so much better a daughter than I deserve. She's smart, she works hard at school, sport, music, and is friendly and nice and unbelievably aware of, and capable of dealing with, different personality types and their social 'comfort' or otherwise. We have a great relationship, she confides in me things I wouldn't always expect. She's the literal example of "having kids is like wearing your heart outside your body". She's more dependent upon parental attention and support than the 15-year old, and not just because of the age difference (maybe it's a gender difference). I'm vaguely concerned about how her transition to real teenage-hood and puberty will change her, but I'm also relatively comfortable in that we've set her up, as best as we possibly could, to not go off the rails.

It's not that I don't love the 15-year old as much, but he needs it less overtly. He's, like, on his own path already, we're just there in case. There was a recent incident in which he actually initiated a hug with me to comfort the both of us. That never happens. But it shows he's still our little dude in there.

Gees, sorry about the rambling on...

Good stuff, thanks.

I consider rebellion as part of growing up. Better earlier, while you still have some leverage, than later. My son waited until his 20s and it's been hell.

Thanks, yeah, we also have a girl on the way and an older boy. Looks like I'm in for a similar adventure. I also left at 18 and you're right that seems young now. But at the time, I remember feeling quite old. :)

> Programming at work is my time off.

I'm often reminded of this comic: https://www.fowllanguagecomics.com/comic/long-weekend/

Made me laugh, thanks! The bonus panel is accurate, too.

My wife and I were in a bind last year, and a younger friend from work watched our toddler for about 5 hours. It was his first time taking care of a small child, and it was eye-opening for him to say the least! It gave him some perspective as a manager as to why folk with kids are always so tired.

My team lead, my manager and their manager are all childless. It's actually been kind of an issue. Maybe I should ask them to take care of my kid for a day or two. As a team building exercise.

I always suspect those people who brag they do 60+ hour weeks continuously without a problem of not being responsible for the care of their kids or their household.

In my view all of the work in our life piles up, whether it is actual work, or driving through traffic, or cleaning the windows or the floors, or preparing the evening meal, or entertaining a toddler. I feel like we have about 80 hours of “work” we can spend in a week without reaching exhaustion, and the more of the non-work “work” we can shift into someone else’s lap, the more of those 80 hours can be dedicated to actual work. Hiring a cleaner, ordering food, taking an uber, hiring a nanny, or just letting a significant other take up the workload, these are all ways to get more actual work done. It is not just about the saved time, it is about the avoided fatigue.

And of course, when you have a household with young children, you quickly come to realize that it is not possible for both parents to have full time jobs and also run the entire household and take care of the kids, and have a personal life on top of that. The only way as a two-income household to avoid exhaustion and losing touch with friends while the kids are young is to have others pick up the chores, whether free (friends and family) or paid. It can be difficult for people that don’t have children to appreciate what a taxing time that is.

I think it's the boredom mixed with the vigilance (limiting this at 1-2 year old). Often they want to be "watched" playing, without you playing. It's super boring and you still need vigilance. 1 hour later, puts you to sleep.

To be fair, when kids are bored, they get sleepy too.

Agreed. I also (personally) find the positivity draining. I used to be kind of a sarcastic asshole. It was a low energy state. Now I'm an always smiling toddler comedy bot, who at any point in time will sing, or juggle for tiny laughter. I don't have the muscles for it yet and the audience keeps requiring increasingly complex routines.

It's true. I have two young ones and I'm a shadow of my old self when it comes to my ability to dive into deep work.

I have forgotten what that was like, which I think is a clever evolutionary self-deception to make having more kids palatable :-)

There’s also something to be said about hiking vs sightseeing or shopping.

A few hours at the mall drains and exhaust you while hiking in rough terrain spends a lot of energy but also gives you a lot of energy.

I think it’s the slow pace and constantly stopping combined with hundreds of small decisions (that doesn’t really matter. “Will my life be better if a splurge on the Pottery Barn toilet brush or should I just get the Tesco?”)

Maybe it's just me, but I find meetings to be way more mentally fatiguing than, say, coding. Even if I'm just listening in.

A 1.5hr meeting cooks me. After a showcase, which can go for 2 hours, I'm done for the day.

However what works for me isn't having a rest, or flicking through YT for some quick mental rewards. A good walk, or doing some gardening, mowing the lawns - basically anything physical - helps me regenerate. Especially being outside.

That's been a big benefit of working from home. Yesterday at lunchtime I just went out back with a skillsaw and cut a whole bunch of wood for an hour (not random cutting, I need it for a project haha). Came back in feeling great!

God yes. If I’m properly ”in the flow” as they say (although it’s rare), then I feel more energetic.

Meetings, especially ones I’m barely relevant to but forced to attend, could probably be an effective sleep aid.

Listening in on meetings is one level of fatigue, but hosting/leading meetings is a whole other level for me. Having to multi-process in order to:

1. Keep discussions on track

2. Give everyone a chance to participate

3. Watch the time and make sure that all topics are covered

4. Take notes

5. Think about what is being discussed and participate

is incredibly exhausting. After leading 2-3 meetings, I feel like I've used up all my mental energy for the day. And as I a writing this, I realized that after leading a meeting, I typically hop out to the kitchen and grab a bite to eat. Maybe that's an instinctual need to refill the calories I expended thinking? Or maybe it's just a reward am seeking after the tiring task...

For me the above is part of it. And our company culture isn't big on sending out minutes (which is bad and good).

The bigger thing that tires me out is the wild context switching of one meeting after the next, on very disparate topics. I'm often left still thinking about something from before, and have to jump to a wildly new topic with my full attention. It's exhausting.

Me too, I could in some days code for an entire day and feel tired but content. Listening in on a meeting for 1.5 hours cooks me as well, especially when I am expected to briefly participate and I can’t take my attention away from it. I love audiobooks and podcasts but there’s something about meetings that makes it feel exhausting.

Weird thing is, you can strengthen this muscle. After years of academia I became able to sit in presentation after presentation and listen to every detail.

At first I could do it for 20 mins, and after a decade I could listen to about 2 or 3 days worth.

It was mostly inane nonsense designed to further someone’s career rather than actual science, but still I could pay attention almost perfectly for hours on end.

In industry I see people switching off after 20 mins in presentations that are actually interesting! Just need to work out your ears.

I lost 2kg trying to center a div once.

Jokes aside. Interesting article. I think the title assumes an answer but in reality the article is a gateway to further studies. Worthwhile read nonetheless.

It used to be so easy when <table> was socially acceptable.

Couldn't agree more.

Straight up raw CSS Grid is my new favorite. It let's you do what we used to do with tables. It even improves it with fr units. Though not sure what to do with the extra brain cycles that don't goto div soup layouts.

Me too. I can't get my head around all the properties for Flexbox, but CSS Grid makes everything so simple.

My latest trick is to swap around the "cells", without changing the HTML markup (generated by simple_form Ruby gem).

It's way easier with flexbox now, though?

Centring divs is now an out of date joke, grandad, get with it. Flex box ruined it.

Seriously, I wonder what the modern equivalent is? Using dev tools to find the source of an unwanted space? What do you mean property X is inherited but only from the last positioned ancestor with a flex size of pi and a negative z index?

It seems like the headline overstates the findings (as headlines are wont to do), but it's interesting nonetheless

> participants who spent more than six hours working on a tedious and mentally taxing assignment had higher levels of glutamate

> too much glutamate can disrupt brain function, and a rest period could allow the brain to restore proper regulation of the molecule

It sounds like the next step is for some studies on the effects of glutamate

Glutamate can act as an excitotoxin. Excitotoxicity is believed to be associated with neurodegenerative diseases.

https://www.frontiersin.org/articles/10.3389/fnins.2015.0046...

https://www.frontiersin.org/articles/10.3389/fncel.2020.0005...

Related- conflicting research findings and anecdotes on glutamate toxicity from MSG consumption might indicate certain people are more susceptible to the negative effect than others. Raising this question often invites comments on: whether or not cautioning against MSG is actually racist; misdirection about the sodium being the prime issue with MSG; and comments from those with vested interest in MSG (MSG producers, any food producer with MSG, Yeast Extract, or "Natural Flavorings" in their ingredients list, etc.)

from the first link:

>L-glu along with glutamine is the most abundant free amino acid in the central nervous system

this would suggest that L-glu is highly regulated in the body. Abundance usually means there should be storage of it if level swings can bring "inbalance" to it's usage.

on top of that, from this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3698427/

>In the brain, Glu, which is locally produced completely de novo from glucose, acts as a major excitatory neurotransmitter, and its activity regulates synaptic plasticity, learning, memory, motor activity, and neural development. But dietary Glu is almost impermeable into the circulating blood. Also there is the blood–brain barrier against Glu in between blood and brain so as to not to incorporate into it the brain.

if high MSG(or just G from other sources) consumption did cause neurodegenerative diseases, shouldn't we see that data clearly in places that consume more in culture?

I think there are two possible explanations for the disparity.

1) Genetics.

2) A leaky blood-brain barrier (which could also be influenced by genetics.) Multiple studies have shown a link between leaky a blood-brain barrier and the same neurodegenerative diseases that increased levels of glutamate are linked to. Things as simple as high blood sugar can contribute to a leaky blood-brain barrier, so it could be more common than we imagine. Tests are difficult to administer, so it's hard to estimate how common degrees of blood-brain barrier leakage are in populations.

if high MSG(or just G from other sources) consumption did cause neurodegenerative diseases, shouldn't we see that data clearly in places that consume more in culture?

If anything, the correlation seems to be negative.

Grandmasters apparently lose 6000 calories during classical chess games [0]. That's a few marathons worth of calories.

[0] https://www.espn.com/espn/story/_/id/27593253/why-grandmaste...

This myth is complete nonsense, I'm not sure how people still share it. The author provides no evidence and simply made some sensationalists estimates based on heart rate and blood pressure during games.

I'm sure they are burning more calories, but I doubt it's 6000.

No one who understands how much 6,000 calories is could make this claim.

That would mean they need to eat 8,000 calories a day for a normal 2000 calorie diet. That's like Michael Phelps level. That's like: leave the tournament, go back to your hotel and eat 7-8 medium dominos entire pizzas in a sitting. I hope I don't need to explain that this is not what chess masters are doing.

After reading Behave, I hold Sapolsky in high regard. Even if he provides weak evidence for the claim, the grandmaster in the article loses 15 pounds- or a whopping 11% of his body weight- on average during a 10 day tournament which is striking.

This can simply happen because of a change in eating and drinking habits during a 10 day tournament.

This take seems overly skeptical to me. Regardless of truth of the 6,000 calorie claim, that kind of weight loss is extreme in such a short amount of time.

To the contrary, you're being underly skeptical. This is a huge claim to base of a sample size of one guy at one event.

To state the obvious that I hope doesn't need to be said to this audience: a sample size of one tells us exactly nothing. What's saying this one guy one time didn't have a nasty stomach bug?

A crazy claim like this requires some kind of study not just one guy's story.

That's a 5200 calorie deficit per day.

So no, not really. At least not without significant dehydration.

I'm more skeptical of the weight loss claim itself.

Well, up to 8lbs could be water weight. If you have excess calories, your body will retain water. If you disrupt that excess you'll rapidly lose 8 to 10 lbs. Weight loss often has great results in week one, then levels off, so a portion of this could be attributed to eating less and increased stress during a tournament.

8lbs if you're already severely overweight or loaded on carbs, maybe. These guys don't exactly look like they are doing either of that. To put it in a different perspective, that amount of weight loss beats out strict waterfasting at the same weight. You can't get much more strict than straight-up dehydrating (because we all know dehydrating yourself prior to a mental exercise is a great idea) or doing rigorous exercise outside of that.

And no, chess is not rigorous exercise. If it was, the room would be too hot for them to wear suits and tuxedos. Those burned cals have to go somewhere. For the unconvinced, try jogging or lifting 2000 calories worth in a suit at room temperature or slightly above without taking it off.

I bet food poisoning would do it. Because, like you said, they aren't burning those calories - 6,000 calories in a single chess game would leave them in a giant pool of sweat.

Dehydration isn't about water, its about electrolytes.

And 4 lbs could be series of bowel movements

I can "lose" 10+lbs in 24-48 hours just by fasting, more if dehydrated.

Of course, defecation must not be confused with burning body mass.

not unless there is such a change, and it has to be significant to loose such weight. what does happen though is an increase in mental strain as the tournament progresses.

Doesn't stress come into play here too?

It could be attributed to stress, perspiration and change in water intake behaviour. In other words water weight.

Still not burning 6000 calories.

> In our study, we found calorie expenditure during chess competition (156.8 ± 65 kcal) and during running exercise (282.9 ± 82.7 kcal) were significantly different from each other, simply due to the overload effect of skeletal muscles during exercise.

https://journals.lsu.lt/baltic-journal-of-sport-health/artic...

This study found that energy expenditure when playing chess was ~2.3x higher than when resting.

And these are just amateur players. Maybe it's not 6000 calories but it is a significant increase over the base rate.

I think people are conflating "weight" with "fat". It's very believable to me that they lost 15lbs in 10 days, some fat, probably mostly water.

I know my weight can fluctuate as much as 10lbs in a day depending on how much I've been sweating, eating, drinking, exercising over the course of the day.

4kg of water, 0.5kg of glycogen, 2kg of debris in bowels. The rest is what they really lost.

Hacker News always has crazy takes when it comes to anything diet related. It's always strange.

I totally agree: it's completely preposterous that they're burning 6kcal sitting still regardless of how much they're thinking. People don't seem to realize how hard it is to burn that many calories when moving. That is advanced athlete levels of caloric burn. Does this caloric burn similarly apply while they're "training", or just at tournaments? Do they need to put down Olympic level meals every day just to sustain?

What about other people who's job is thinking? Are mathematicians also forced to devote a significant part of their day just to ensuring can chew through 6000 calories worth of food? Or is there something about board movements that consumes extra calories? L shape? 3 calories. Straight line: one calories. If we could pin down which type of thought burned 100x more calories, we'd be onto something powerful here.

> Hacker News always has crazy takes when it comes to anything diet related. It's always strange.

HN has crazy takes on everything not within the very narrow sphere of tech expertise that is common to everyone on this board.

You notice it for diet-related things since you are a (relative) expert on that topic.

But it's also the case for anything economic, political, scientific, or sports or hobby related, and so on.

I don’t agree. I’m better versed in politics than most and HN comes across as naive about it, but not crazy.

Nutrition seems a whole new ballgame. I’m going to speculate it’s because we know pretty much nothing about nutrition, and to hackers that’s unacceptable. We like to know the rules so we can hack them. But in nutrition no one even knows the rules, maybe the rules are different for different types of people, and that’s deeply unsatisfying.

Actually, it is not HN, but generally nutrition is one of the most bullshitted topics in the world. Everyone has their perspective completely conjured up from thin air.

I don't trust any of these from any person:

  Nutrition
  Financial Advice
  Audiophile Advice
  Home therapy

>Hacker News always has crazy takes when it comes to anything diet related.

HN comment sections are useful only when it comes to tech/business/programming subjects now, and even then the noise to info ratio is getting quite high. Turns out in the 21st century intelligence and knowledge no longer span across subjects as universally as the 18th century.

If my estimates are correct, 6000 calories is approximately the energy it takes for a 75kg person to vertically climb 34km.

The article claims that breathing rate TRIPLES during chess tournaments. I don't know if that's true, but if it is, then there is something pretty intense going on. If I tripled my breathing rate for an extended time period I'd probably pass out or something.

6000 calories seems absurd. But having played chess tournaments I have lost a bit weight during them despite eating generous amounts of bacon, eggs, hash browns etc at the hotel breakfast, then more crappy fast food in the evening, with mostly sleeping and relaxing in between. So I feel like there must be something to it. Although 6000 kcal in one game is ridiculous, even factoring in nervously pacing the playing hall when it's not my move.

6000 calories, about 4 pizzas, or couple of marathons.

But it may not be because of a more intense brain activity : https://news.ycombinator.com/item?id=31130717

Thinking is a bottomless pit for attention.

Put X attention into digging a hole and you get that much hole dug.

Put X attention into sandwich-making and you get that many sandwiches made.

But with thinking there's no real connection like that. You can put a whole decade of attention into a bunch of thinking and achieve zip.

It's an amazing attention sink. Whole mountains of attention can disappear. Easily. Casually.

And then when you consider that many of us basically think all the time. Habitually. Chewing over... memories and dreams and plans and stuff. Woah!

And that attention is our energy budget. Flushed down the thinkhole.

Can you go without thinking for an extended period of time? I have split seconds here and there when I get the feeling I haven't thought about anything for a while, only to interrupt the streak with the very act of noticing.

Yes I can. That's sorta what we do in this one meditation technique called vipassana. I've been doing it for a few years.

When you get out of the habit of doing stuff with your attention all the time (thinking etc) then your attention moves in a new way. It sorta grows. It's pretty great.

I've noticed this phenomenon anecdotally. It seems like my impulse to NOT eat junk food goes down significantly on the days I drive home after working on a hard mental problem. On easy days, I'm craving celery.

There was an old (but popular) study that showed people were less likely to make healthy snack choices when they were asked to memorize more digits.

https://www.jstor.org/stable/10.1086/209563#metadata_info_ta...

"...a challenging task: for example, watching letters appear on a computer screen every 1.6 seconds and documenting when one matched a letter that had appeared three letters ago."

It seems like they're conflating "stressful" and "thinking hard". IE, Is this "thinking hard" or is it "maintaining constant alertness"? I think things like staring at screen tax more than the brain as such.

I spend most mornings working on math, programming and philosophy. This doesn't make me feel tired. Neither does playing the game of Go without a time limit. I assume all those tax the brain itself. But Zoom call will absolutely make me feel tired regardless of the subject.

And "stress" could cause a build-up of glutamate or whatever in the brain also.

They used the N-back task, a standard task used for inducing mental effort (e.g. [1]). So in this case they have N=1 for the easy group and N=3 for the hard group. Then they compared glutamate concentration across groups.

I'm don't disagree that "thinking hard" is poorly defined. But they did control for staring at a screen.

[1] https://journals.plos.org/plosone/article?id=10.1371/journal...

More discussion on the article in Science here: https://news.ycombinator.com/item?id=32435019

Top commenter there seems to find the reporting problematic. I’d love to see more discussion in that thread from anyone who is knowledgable.

I'm now wondering what, if any, connection there is between glutamate regulation and depression, since listlessness and fatigue are common and characteristic symptoms. To scientists: More research, please!

I'm not scientific about it (n=1, after all), but I've realized from my own diagnosis and coming out of it that depression is a complex abstraction:

1. Reactionary primary emotion (e.g., shock, surprise, confusion)

2. Add the perception of injustice to create the secondary emotion of anger

3. Have anger directed toward meeting an unmet need

4. Give hopelessness about attaining that unmet need

5. END IF nothing gives that hope to meet that need that the anger was directed toward

edit: fayled at phormatting

In my own struggles with depression, I can't really pinpoint any anger/injustice most of the time. It's more just "anxiety leads to inaction leads to ruined or missed opportunities leads to insecurity and low self esteem leads to hopelessness leads to 'why bother-ism'." Then again, my depression is comorbid with an anxiety disorder, so perhaps it's different from someone who has only the depression shrug

Beautifully put. I think this is very interesting to contrast with the also-well-put GP commenter. Different flavors of sadness.

I didn’t know this was a phenomenon. I have been thinking of hard problems to fall asleep at night for years

Thanks for sharing that idea! I look forward to trying it out tonight.

Sadly the more likely consequence is that you might fall asleep quickly then wake up a few hours later and find yourself still thinking about it, and that second time your brain refuses to shut down until it solves it. Or maybe that's just me.

Same thing happens to me. I’m actually jealous of people that can code at night. I have such great ideas from 9-11pm, but if I actually write any code, I’m guaranteed to be up from 2-4am.

I have the opposite problem - if I'm thinking too hard near bedtime about financial math or boolean algebra for example, I won't be able to sleep. My brain is too active going through all the calculations in my head.

If I want to fall asleep within 5 minutes, what works for me is varied physical and mental exercise throughout the day, and an easygoing book or movie near bedtime.

If there's something stressful going on the next day, a tech-nerd podcast like ATP helps me forget about it and get to sleep. But I try not to let late night podcasts become a habit - sometimes they get too interesting and I stay up for over an hour to keep listening.

I'm the same way, I may become exhausted, I can feel myself being exhausted by my mind won't let me sleep.

For me, it has to be really hard, not like some leftover work you didn’t do that day. The more open ended the better. For example, how to make a transistor out of readily available household components. How would you do lithography, doping, etc.

Jesus, that line of thinking is a recipe to keep me up for days. How you could even begin to fall asleep with a line of thought so interesting is beyond me.

I guess it works because you're not personally attached or motivated at solving them.

So it comes down to counting sheep type of distraction.

Like others echoed, if you pick an open ended unsolved mystery that is literally on your shoulders during the day, you'll be unable to switch off.

Truth, reading technical books before bed was a fantastic strategy to fall asleep fast. I don't do it anymore because I'm trying to take better care of myself and prevent/recover from burnout but damn does that work well!

It's really obvious with our dog.

As a puppy we could walk for an hour, or even more than 5km, and at home he'd still be a rambunctious little pest because he might be physically tired but not mentally. But a 5-10 minute training session, where he has to think? Out like a light on the couch for hours. I imagine it hits dogs harder than us because they're less suited to problem solving and intense thought in general. Now he gets bored if he doesn't get his training but a couple of sessions a day are good for him and easier than a long walk (shorter walks suit him fine now).

Very fascinating discovery!

I wonder if this may be linked to Type II Narcolepsy, which currently doesn't have a known cause. Type II narcolepsy requires very short naps that come on suddenly, like a computer reboot, then the brain is back in action!

Not a doctor, so I might be stating the obvious to anyone who is, but couldn't this explain why exercise seems to make people feel more energetic? If a buildup of pollutants in the brain can make you feel fatigued, then better cardiovascular fitness and healthy kidneys would help clear these pollutants out more effectively, right? It isn't that you have more energy, it's just that being healthier is helping clear the things that make you mentally fatigued.

I guess you could also turn this on its head for people with chronic fatigue by looking at their cardiovascular and kidney function.

Can definitely confirm that exercise reduces my stress levels and improved my intellectual capacity. It is almost universal advice to startup founders to exercise frequently, and I think there’s a lot of personal experiences behind that.

I do 4 hour long OReilly trainings. These are to about 100 people online you can't see or hear.

The first time I did it, it was so stressful that I couldn't stand up afterwards - my legs were so tired. I also needed to switch my brain off afterwards, so drank quite a lot of alcohol.

Let nobody tell you that desk work is not physically demanding work!

I always wondered how we feel being tired - whatever the underlying reason is. Where in the brain does it happen, what system does the perception of beeing tired - reporting it to consciousness? Also, it must exist to stop something harmful to happen to the brain or other parts of the body. Something else: Abnormal fatigue happens after brain injuries but also in depression. In brain injury some basic mechanism - like transmitter metabolism my be damaged, and cause the fatigue, but may fatigue also protect the psyche in some way, or may it sometimes give "false readouts"? I'm amazed how little we understand, but even more that nobody seem to ask the question about or investigate the question of the "tiredness-perception-brain-curcuit".

No, it's definitely in study and a lot of computational models of how these mechanisms may work were put forward.

Most definitely it has to do with "to stop something harmful to happen to the brain" but since the brain is such a huge interconnected mess, it's difficult to make a grand statement.

An analogy with weight-lifting (or long-distance running) is easier: when you are lifting weights sometimes you reach failure and you think you can go no further, but usually this is a message having to do with the body parts you are exercising just being to hot... some weight-lifters quickly cool down the palms of their hands (under the arms, under the feets, etc...) and can continue lifting.

Is very simple, you don't want to cook yourself, but the message that we consciously feel is akin to, "I can't go no more" when instead by lowering body temperature, you can come back.

So one factor, definitely, is temperature (you don't want your brain to get too hot) but also is the rate at which you can recreate new neuronal connections (when learning for example. And what are the constituents of these new neuronal pathways? Do you also delete?)

These are only two factors and there has to be a whole panoply of them (electrolytes, vitamins, glucose, dopamine, etc...)

> At the end of their work day, these study participants were also more likely than those who had performed easier tasks to opt for short-term, easily won financial rewards of lesser value than larger rewards that come after a longer wait or involve more effort.

I wonder if this has any implications on the "ego depletion" model, which has had a checkered history in reproducibility:

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

After some intense code challenges I did felt exhausted. I learn a lot too because they were out of my comfort zone. I felt like kind of needing to recover resting more the next two days.

When I’m thinking through a hard problem something I’ve learned to feel/notice is an oncoming massive migraine unless I supplement some magnesium, multivitamin, nootropics or easy to digest amino acids to give my brain the essential elements it needs to perform. I recall our bodies do not produce magnesium. This advice is on top of being properly hydrated, otherwise I will have impaired cognition and brain fog until proper hydration + supplementation is achieved.

Can anyone relate?

They should study people who spend 6 hours in meetings next.

Meetings are taxing. You're trying to ingest the presented information, social cues/emotional states and often times keeping an eye on slack or what have you.

Being poor takes a huge amount of mental effort. This would explain in physiological terms why it's hard to make good decisions when you're poor.

I think this line of research is necessary in helping us (society) understand ourselves better. Although I've not been poor myself, the ongoing mental stress/strain when met with challenges in which I feel I stand a high chance of failure (e.g. job interviews when I was a new graduate, finding a PhD advisor, submitting first paper for publication) has led me to making poor diet, exercise, and sleep decisions. I would imagine that the poor are faced with an even greater amount of stress in terms of food security, relationship strain, and being cast in a negative light by people around them; making it, as you put it, physiologically harder to make good decisions.

This has always been an embarrassing issue for me: Lose track of the lecture. Try really hard to concentrate and catch up. Nod off.

I suspect that nodding off in meetings or lectures, a lot of time, is caused by too much CO2 in the air, caused by poor ventilation and a room full of exhaling people.

Then why does spending all day in stupid endless meetings make you feel even more tired?

To some extent, lack of fresh air in closed rooms

yeah, no it's the other people. meetings have a collective IQ of the dumbest person in the room divided by the number of participants.

Looks like an interesting article, too tired to read it though. XD

I use books on theoretical physics as sleeping aid. It makes me feel tired quickly and I can sleep very well on it.

Does thinking hard burn calories/contribute to weight loss?

Reading this article makes me feel tired.

Solution: stop thinking. Sign me up!

Yeah, take some breaks. Also don't refuse to take vacations.

Brilliant work, and the researcher involved seems quite humble, despite her impressive discovery.

Where in the world is Carmen Sandi’s ego?

the article merely said the obvious: thinking makes you tired--without providing any workable solutions. typical of the pedants and grant-whores.

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