I've also been interested for some time in how metabolism works and wanted to debunk the popular myth for my friends that exercise burns a lot of calories, since I was under the impression that around 80% of energy we burn is just by "living" - breathing and thinking.
Reading this article I'm a little confused by the author's conflation of brain energy and the energy expenditure of the body as a whole. In the beginning they mention:
> "Your brain consumes roughly 20 to 25% of your body's total energy at rest"
while later they say:
> "Even chess grandmasters, who sit for hours in states of intense concentration, burn only about 1.67 calories per minute while playing, compared to 1.53 calories per minute at rest"
That second figure seems to refer to whole-body expenditure, not just the brain. And intense cognitive work doesn't happen in a metabolic vacuum - there's increased cerebral blood flow, elevated sympathetic nervous system activity, changes in heart rate variability, hormonal shifts (cortisol, adrenaline). These all have systemic metabolic costs that go beyond the glucose the neurons themselves consume. So the "it's just a banana and a half" framing might be undercounting by quietly switching between brain-only and whole-body measurements.
Also somewhat related - the link to businessinsider about chess grandmasters is broken, but another very interesting rabbit hole here is how energy expenditure is actually measured. A lot of what consumer devices and even many studies report is based on proxy biomarkers like heart rate, HRV, weight, age, and sex, run through linear regression models. True calorimetry (indirect via gas exchange, or direct in a metabolic chamber) is expensive and impractical outside lab settings. That means the precise calorie figures cited with such confidence - the "100 to 200 extra calories" from a day of thinking, or the per-minute burn rates of chess grandmasters - likely carry wider error bars than the article suggests. We don't really have a great way to measure real-world energy expenditure accurately at the individual level, which makes me a bit cautious about the neat narrative of "thinking is calorically cheap, full stop."
That said, the core point about adenosine accumulation and perceived exertion affecting training quality is fascinating and well-supported — that part of the article is genuinely useful regardless of the calorie accounting.
> debunk the popular myth for my friends that exercise burns a lot of calories
Depends on your level of exercise. I often cycle 100km per day and can tell you if I ate only the 2000 kcal I hypothetically need I would go into a strong deficit.
> if I ate only the 2000 kcal I hypothetically need I would go into a strong deficit
Right, and that's kind of my point - the "2000 kcal" figure is itself part of the problem. It's a rough global average that doesn't account for your sex, age, weight, body composition, activity level, or even climate. It's a number on a food label, not a physiological reality for any specific person.
And even if you could nail down your actual total daily energy expenditure, calorie counting treats all calories as equal, which they aren't. Your body spends 20-30% of the energy in protein just to digest and metabolize it, compared to 5-10% for carbohydrates and 0-5% for fat. So 100 kcal of chicken breast and 100 kcal of butter are not metabolically equivalent - your body nets significantly less usable energy from the protein. This is the thermic effect of food, and it alone accounts for roughly 10% of your total daily energy expenditure.
Speaking of which - basal metabolic rate (just keeping your organs running, blood circulating, cells maintained) accounts for about 60-70% of total daily energy expenditure. Add the thermic effect of food on top and you're at roughly 70-80% of your energy budget spent before you even stand up from bed [1]. Physical activity - including your 100km rides - typically makes up the remaining 20-30%, though obviously that range is wide and shifts dramatically for endurance athletes.
So yes, of course people who cycle 100km need more fuel. Nobody is disputing that. My point is that most people vastly overestimate how many calories exercise burns relative to what their body spends just existing, and they use kcal as a universal unit of nutritional value when the body's actual energy extraction varies significantly by macronutrient composition. People optimizing purely on calorie numbers are working with a model that's far rougher than they think.
And this whole picture gets worse with wearables pushing calorie counts front and center. You see it all the time - "my wearable shows that i burned 300 kcal with that activity so it zero outs that sweet thing I ate earlier that was also 300 kcal" That's wrong on multiple levels - the device estimate is inaccurate to begin with, the thermic processing of that pastry isn't equivalent to the "300 kcal" on its label, and your body doesn't do neat arithmetic like that anyway. But with every fitness app and smartwatch plastering a big kcal number on your workout summary, it's becoming the default way people think about food and exercise, and it's reinforcing exactly the wrong mental model.
That specific aspect might end up irrelevant for dieting, which is exciting since it flies in the face of intuition. It seems that when it comes to long-term modes of existence (as opposed to, say, the one day of the marathon) the "activity level" doesn't really affect how much energy your body uses.
> In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size.
> Can you expand on that please? Because I can tell you as a matter of fact that when I go for a run for an hour I burn well over 800 calories
Sure - how did you arrive at the 800 kcal figure? Most likely a wearable or an app, and those estimates are based on rough linear regressions from weight, age, sex, and heart rate - not actual calorimetry. The error margins on those numbers are significant, but the devices present them with false precision that makes people treat them as ground truth.
Even setting accuracy aside, the framing is the issue. Your basal metabolic rate - just keeping your organs running, blood circulating, cells maintained - accounts for 60-70% of your total daily energy expenditure. Add the thermic effect of food (~10%) and you're at roughly 70-80% of your energy budget spent before you even lace up your shoes [1]. Exercise typically makes up the remaining 20-30%. So that hour of running, while genuinely beneficial for a hundred other reasons, is a relatively small slice of your total daily burn. And not all calories are equal on the intake side either - your body spends 20-30% of the energy in protein just to digest it, compared to 0-5% for fat, so "800 kcal burned = 800 kcal of anything eaten" doesn't hold up.
That's what I mean by "myth" - not that exercise burns zero calories, but that the popular mental model of "I ran for an hour so I earned X calories of food" is built on inaccurate measurements, treats all calories as interchangeable, and overweights exercise relative to what your body spends just existing. Curious though - do you track your intake with the same rigour, and if so, do you find the numbers actually add up in practice?
> That's what I mean by "myth" - not that exercise burns zero calories, but that the popular mental model of "I ran for an hour so I earned X calories of food" is built on inaccurate measurements
Over the last few of decades there's been a lot of lab research calculating the gross efficiency of the human body with different factors (size, sex, fitness etc) and I think these estimates that sports apps give are very close.
If you cycle with with something that can measure power output you can calculate the mechanical work done by the body exactly during that exercise period and convert to energy "burnt" (1 watt/hour = 3.6 kJ = ~0.86 kcal). 220 Watts for an hour (I couldn't do that but a good cyclist can) is about 800 calories.
I tracked intake, calories burned(from Apple watch with activity tracking turned on for any specific exercise) and weight for 12 weeks as part of 75 hard and found my daily weight decreases were exactly in line with what you'd expect given the estimated deficit 95% of days and 100% at the weekly level.
I don't track consistently anymore only when I'm working towards a goal but when I have more than 2 weeks data these days it seems pretty spot on to the point I can calculate the tracked captors to target to get the desired rate of change in weight pretty consistently.
Thanks for fleshing out your comment. Because initially it did kind of suggest to me you were saying it burns no calories or makes _little_ difference.
I agree with all you posted.
> Curious though - do you track your intake with the same rigour, and if so, do you find the numbers actually add up in practice?
To return the courtesy, for the purposes of discussion I picked a rough estimate and rounded down significantly the actual amount I typically run. More often it's 1.5 hours a run and supposedly >1000 calories given my weight, heart rate, terrain, and speed. I also assumed the calculations are way overestimating my actual calories spent so just went for something somewhat plausible for the sake of a HN comment. As you noted calories aren't accurately reported by devices. I do not pay attention to it in massive detail either. But in practice since I run an average of about 25km a week but can vary from 0 for some weeks to 50 for others and I keep relatively good eye on my diet I notice significant changes in weight over time that tallies with effort. Three months of below that 20ishk a week and I will put on 2-3kg. The next three months I increase to 35ish+ a week and it drops off again. Would I swear to it in a court of law that I'm not miscounting meals? No way. But I feel reasonably comfortable that this is an accurate description.
I think OP may be referring to the idea that the total number of calories burned in a day doesn't meaningfully change under a workout regime. Working out does burn calories, but after a few session your body starts to compensate by burning less calories in other areas (e.g. immune and reproductive system). The net result is close to zero, except in very demanding workout regimes.
I don't have the background to fully evaluate how true that is. I read "Burn" by Herman Pontzer, which at least makes a very good case for it.
I seems like it's only part of the story. If you increase exercise but also increase calorific input to match then you won't lose weight. But, the laws of energy conservation being what they are, I don't think anyone disputes that if you very significantly increase exercise but also maintain calorific input then you will lose weight as the energy must come from somewhere and there are only so many optimisations your body can make. You could of course maintain exercise levels and reduce calorific input for a similar effect, ignoring health benefits of exercise. Take an extreme case, Michael Phelps. He used to eat 12,000 cal a day because of the hours he spent swimming. Certainly not a small guy but pretty lean! So I'm totally prepared to accept there are bounds to all these statements but I still think I couldn't finish an 800 cal sandwich for lunch hehehe.
By the way, I feel the Wikipedia page there uses a lot of words suggesting that the paradox isn't at all fully understood and that there could be compensating mechanisms we aren't aware of. But I'm not in a position to dig deeper.
> I don't think anyone disputes that if you very significantly increase exercise but also maintain calorific input then you will lose weight
This is exactly what is disputed by the link you posted. They measured directly the energy expenditure (the number of calories burned by respiration) in a high-activity hunter-gatherer tribe, and in relatively low-activity industrialized societies, and found they were almost the same. So the number of calories the people consumed was not measured or relevant (and must also have been roughly the same if neither group was actively gaining weight).
Not quite, imho. The language used here is subtle and I could be clearer myself. It talks about the paradox that suggests the work _appears_ to come from nowhere, which we should all agree is impossible, thus a paradox, not that it does actually come from nowhere. Just that we don't know exactly where. The page doesn't offer an explanation for the appearance of the paradox.
For me the line "The studies suggest that controlling caloric intake may be more necessary for managing weight than exercise alone." is a possible conclusion for the apparent paradox. Note the words "may" and "alone" which indicate uncertainty. I deliberately used the phrase "very significantly" to suggest we would probably all agree that there is some bound on observing the paradox which is why I used Phelps as an example. To repeat and be clear, I think the paradox as described on the page does not say that with a very significant increase in energy expenditure there will be no weight loss with a constant calorific intake.
I guess when you say "work" you mean precisely mechanical work. If so, I don't think it is implied anywhere that the work "comes from nowhere". If a person is doing mechanical work then that work must come from respiration, ultimately. There is nowhere else for it to come from. If a person does 2000 calories of mechanical work and consumes 2000 calories of energy then there is nothing left over for anything else, and they would lose weight one way or another. But this is much more extreme than what was observed, or what happens when a person ordinarily does exercise.
The "Energy paradox" is not a logical paradox at all. It is just a confusing fact. The observed fact was that two different groups with apparently very different activity levels respire almost exactly the same amount. In other words, that an increased, but not necessarily extreme, level of mechanical work does not appear to correlate with an increased level of calorie burn. Not just that the relationship is non-linear, that the relationship does not seem to exist at all (at the measured level of exercise).
I was very careful with my words this time, hopefully there is no more misunderstanding. I think we still disagree unless by "very significantly increase exercise" you mean something like running multiple hours per day every day.
And also that the calorimetry from wearables is highly flawed and it seems to that we don't have super accurate data and what sort of activities burn the most energy.
I am also a big opponent of folks that start equating the "my wearable shows that i burned 300 kcal with that activity so it zero outs that sweet thing I ate earlier that was also 300 kcal" which is wrong on so many reasons but with a lot of workout apps and devices pushing the (inaccurate) kcal count front and center becomes more and more a of a thing.
I think it sort of depends on how you look at it. If 800 is an hour of running - that's probably "a lot" for quite a few people. But 800 is also just a sandwich. Which isn't all that much.
So if you view this from a time use perspective, just skipping that sandwich is way better than running for an hour. And many people can't spare an hour a day just to make up for a sandwich. Hence - "not a lot" - Its too expensive time-wise for the caloric balance effect it provides. Just skip the sandwich instead.
I agree with the general message, but I'm curious what ingredients go in your 800 calorie sandwich. That's more than a double Big Mac with 4 patties (780 kcal)!
You need to eat roughly somewhere between 1300 and 2000 Cal every day to maintain your weight even if you are doing to exercise at all.
If you want to lose weight, it's far easier to remove 800 Cal from your diet, at least time wise, then it is to exercise 800 Cal's worth every day.
Either way, if you're losing weight at any appreciable rate, you will feel hungry (at least if it's not chemically induced in some way, such as chemo or GLP-1 inhibitors or similar). That's just something you have to get used to if you want to lose weight.
This is well-intentioned but I think it oversimplifies in ways that can actually be harmful. "Just get used to being hungry" is rough advice to give people - chronic hunger is one of the main reasons diets fail, and framing weight loss as a willpower contest against hunger ignores that satiety is heavily influenced by _what_ you eat, not just how much. A 400 kcal meal of protein, fat, and fiber will keep you full for hours; 400 kcal of simple carbs will leave you hungry again in 45 minutes, in part because of the insulin and blood glucose dynamics involved.
The calories in/out model isn't wrong exactly, but it's so reductionist that it becomes misleading in practice. It omits hormonal responses (insulin, leptin, ghrelin), the thermic effect differences between macronutrients (your body burns 20-30% of protein calories just processing them vs 0-5% for fat), gut microbiome composition, sleep quality, stress hormones, meal timing, and individual metabolic variation. Two people eating identical calorie counts can have very different outcomes. Telling someone "just eat less and accept the hunger" without any of that context can set them up for a miserable yo-yo cycle - or worse, a disordered relationship with food.
No, the common "wisdom" you are puppeting here is harmful because it just doesn't work.
We have been telling people for decades now to be worried that they might harm themselves by too much restriction and it is just wrong. What is harmful is being over weight. What is harmful is then confusing people that they are somehow going to lose weight without much restriction or being hungry.
This also scales really bad with age because as you age the CNS recovery gets worse and worse compared to muscle recovery.
At 55, there is simply no way for me to lose weight other than being hungry. It is impossible to recover from the amount of exercise that would be needed. The reality is that no one needs to worry about too much restriction until they are down to around 12% or so body fat. The fact a person's bodyfat % is never mentioned in this is exemplary of how bad the standard advise is.
Most people have too much leptin and leptin resistance. Then those same people get the same bad advise over and over to not restrict too much because you don't want to be like an anorexic or extreme athlete and have too low of leptin. Of course, ignoring that the anorexic and extreme athlete are going to have incredibly low bodyfat percentages.
For cardio sure but for weight training you're burning calories and tearing muscle fibres to increase size/strength. Also depending on the running you're doing, you're likely staying fitter.
Sure it's easier to fast but you're missing out on the other benefits associated with exercise.
Not running, but in cycling we have power meters, and some workouts (eg 2 x 20' threshold) will definitely burn in the range of 800 calories in an hour. The energy measured by the power meter for this workout is 800 kJ for me (my threshold being around 260W). Now it turns out the conversion factor from kJ to calories is 1/4, but the body is only 25% efficient when producing calories for cycling, meaning one has to burn 4x the amount measured by the power meter. So that's 800 calories for this kind of workout, for me. I wouldn't be surprised if runners of similar fitness doing similar workouts had the same energy expenditure.
I found the AI writing of this post to really detract from its message. Give your agent meaningful writing samples of your own work and use those as a ‘style transfer’ basis for blog posts to get something far more true to your own voice.
Who would read a blog post that just says "Think of a topic that users of an app for monitoring blood oxygen might be interested in, do a web search for related articles and synthesize them into a blog post. Make sure to draw on your own personal experience to make it more engaging"? I'm sure the actual ad at the bottom had more human effort put into it than this article.
The website owner didn't even bother to check for hallucinated links, though https://journals.physiology.org/doi/full/10.1152/japplphysio... does exist and somewhat backs up the clickbait headline, so it would be satisfying comeuppance if the mods could just replace the submission accordingly.
It's well-structured and the message is clear. Are we intentionally prompting LLM to write badly now? Do we have to manually write bad essays to avoid AI accusation?
It's just so cliche. The dramatic transitions which introduce things that aren't as important as the transition itself. The flow is very AI, short dramatic responses to a previous question that's also not "groundbreaking" enough to warrant such a style. It's just hard to unsee these things. Idk man, I guess if you like it, that's great but I cringe when I read this and I never finish reading because I assume the author put in minimal effort so why should I?
I mean... this is an ad for their app and the purpose is to make you click more articles on their blog. Even if it's written by a human it doesn't justify much more time reading it. If there are jobs deserving to be replaced by LLM, this kind of copywriting is on top of my list.
Usually, I can easily tell bad AI slop, because it is just that - sloppy - the bullet points, the 'delving' and all that.
But how can you tell this article was also AI-tainted?
On a second skim, I can sort of sense some of it - the bulletpoint-enthusiasm, the idiosyncratic segues (?) that link sections/paragraphs of the text.
But it didn't trigger for me immediately, or cause me concern..?
I'm worrying that soon, I will have to hunt for non-AI essays by them just being worse written/more 'crude' and not as eloquently written as an AI would do :-/
Basically, seeking out "authentic human slop".
It's very clear to me on its face that it's AI, but not "obvious as the sky is blue" others seem to be implying. I would dislike the writing style even if it weren't AI.
For the record, an AI detector that appears to have put work into reliability and that I trust very much from my own testing, Pangram (https://www.pangram.com), says this is 100% AI generated. I've used it plenty before when experimenting with AI-collab writing, both fiction and non-fiction, and it's frustratingly accurate in identifying what is and isn't my contribution. I have since largely given up trying to do AI-collab writing, because no matter how nice the writing looks in the moment, it always reeks when read closely, or on later days.
Passages like this one suggest that maybe it was an AI rewrite, rather than from scratch:
> I experienced this pattern without understanding it. My Tuesday evening interval sessions, scheduled after long workdays, consistently felt worse than my Saturday morning sessions. I blamed sleep, stress, hydration. Those all matter, but the research suggests the cognitive load itself was a primary culprit.
You really couldn't tell? The overly dramatic transitions all over the place is such an obvious tell:
> Here's the part that surprised me:
Might as well have said "here's the kicker" and used emojis instead of bullets. Maybe you can share your reading sites as you seem rather undrrexposed to not recognize this immediately lol.
Edit: I mean come on man, how can you not tell?! I'm still cringing from this one:
> The incremental cost of actually thinking hard? Almost nothing.
I wanted to test my theory that "don't use cliche'd language" helps with that, but incredibly the essays ChatGPT is giving me today don't have any of the tells. How do I get it to give me slop?
I asked "Can you give me a short essay on the history of fire." Maybe the type of writing requested has a massive effect on the language used?
Why is this AI writing accusation necessary? Plenty of humans write this way. Have you ever read pre-AI content marketing articles? If you've learned a bunch content marketing advise then you'll see those patterns that you now associate with "AI writing" were already all over the place. Baity titles like "Why it's bad that X did Y" or "<explanation of the problem>. Want to be freed from worrying about this? Use $OUR_BRAND", urgh, once you learn those patterns you can't unsee it.
Granted, you don't like to like this style of writing, I don't either. But you don't have to auto-accuse AI writing either. Also, there's nothing wrong with using AI to rephrase a manually written text for better readability, plenty of people use AI for that too rather than writing the entire thing.
Was expecting the article to mention creatine which interacts with ATP. It's a supplement that's so well studied that almost everyone should take it, even if you don't workout at all.
In my experience it has helped tremendously with mental endurance (n=1 but there are some studies that support it, especially in older people with cognitive decline).
In my experience, it's the workout itself that ruins sleep when it's in the evening. My theory is that it's because of the adrenaline generated by muscle strain.
Creatine monohydrate (and seemingly HCL too, though not tested long term) kind of makes me constipated. I'd like to take it, because I lift weights quite often, but it just messes with my stomach too much.
Second anecdote, I take between 10 and 15 grams. I don’t experience cognitive effects at lower doses (though my weightlifting endurance is still higher on lower doses). I also don’t eat meat so don’t have any incidental consumption
One of her creatine videos mentions that your muscles will take up ingested creatine faster than the brain. So for any creatine to make its way to the brain, your muscular creatine stores must be topped up first.
I think dosage would depend on the amount of daily physical activity. If you work out a lot, you'd have to replenish your muscular creatine stores before the brain could access any/much.
She also mentions boosting creatine dosage after bouts of mental exertion.
To add another data point, a 2024 study [1] on the mental effects of single doses of creatine was using 0.35g/kg of creatinemonohydrate, or about 28g for a typical adult male. Though obviously high doses are safer if you just do them once
And an earlier 2018 article [2] argued that "Evidence suggests that the
blood–brain barrier is an obstacle for circulating cre-
atine, which may require larger doses and/or longer
protocols to increase brain creatine as compared to
muscle. In fact, the broad spectrum of creatine sup
plementation studies that span different dosing pr-
tocols (e.g. high-dose short-term, low dose longer-
term), co-ingestion of other nutrients/compounds
(e.g. carbohydrate, protein, insulin), different popu
lations (e.g. vegetarians, elderly, patients, athletes)
is unavailable for brain creatine adaptations"
Meat is one of the primary sources of dietary creatine, but still provides overall very little (~2g/pound of uncooked red meat). There isn't much to make up for in a non-meat eater and the 5g should still be fine.
Shouldn't the chemistry hide the usage of calories by the brain? It gets basically a supply run at night - when its washed with lymph, sugar supplied and then subsists on that for new memory formation and computation with small scale supplies delivered during the day via the blood stream? So a hard thinking experience should show up downstream as calorie usage during the following sleep?
Is anyone here able to offer an explanation for why our brains are able to do really complex tasks without using much energy, at least compared to AI systems?
The brain relies on discrete, sparse events in space and time to handle computation.
Most of the computation and learning that occurs is attributable to the relative timing of spiking events. A lot of information can be encoded in the delay between 2 spikes. The advantage of biology is that there is no explicit quantization of the time domain that must occur. Biology gets to do a lot of things "for free". Simulating causality in a computer in a similar way requires a priority queue and runs like ass by comparison.
The way neurons and synapses work you spend a lot of energy keeping them ready to fire. How often they actually fire is a smaller cost compared to maintaining them in ready state.
We end up using 100W (2000kcal/day) for the whole body, or about 20W for the nervous system alone (though a nervous system alone wouldn't be able to survive). That's comparable to what a modern laptop uses. Sure, that laptop can't run a large LLM at any reasonable speed, but it can do basic math far better than my brain. By a comically large margin. Just a consequence of the very different architectures chosen
Current AI systems aren't biomimicry; they run a simulation of something vaguely similar to neurons. This is rather like "why does it take more processing power to emulate a PS2 than the original PS2 had".
Why would they not be? A brain and a computer are completely different things. They don’t do the same thing and they don’t work the same way at all.
"Artificial neuron" was a useful metaphor at the beginning, but they really are a very simplified model based on what some people understood of neurology back then. They are not that useful to get insights into how actual neurons work.
My thinking was that its sort of like an engine spinning at idle vs when the gear's engaged, in either case the engine is still spinning and using fuel, just more so when its engaged, as opposed to an electric motor.
I know the metaphor isn't exact, it's just how i thought of it.
Because computers use digital circuits which are not allowed to make mistakes, i.e., they amplify each signal during every step as it passes through the system.
If I'm not in flow state focusing on some programming problem, my brain is still going a million miles a minute pontificating about 10 different threads of nonsense at once. So I could see where focusing on one task doesn't actually burn any more energy, it just pulls in all those other workers and puts them to work on one thing.
The product that this article is advertising seems to be pretty inaccurate and their marketing seems to be burying that information.
The big copy on the front page says:
> Your Apple Watch *tracks* VO2 Max—one...
While you have to read through FAQ where you see:
> The watch *estimates* your cardio fitness during outdoor activities and stores it in Apple Health, which our app reads automatically.
All emphasis are mine.
I think it's a little disingenuous to sell this as "Your VO2 Max, finally visible" when it's actually just an estimate from a watch, based on biomarkers. When the real VO2 is measured in a lab with a more involved equipment.
A 2025 validation study involving 30 participants found that Apple Watch underestimated VO2 max by a mean of 6.07 mL/kg/min (95% CI 3.77–8.38) when compared to indirect calorimetry, the gold standard method. The mean absolute percentage error (MAPE) was 13.31%, and the limits of agreement showed considerable variability ranging from -6.11 to 18.26 mL/kg/min [1]. Another 2024 study found similar results, with the Apple Watch Series 7 showing a MAPE of 15.79% and poor reliability (ICC = 0.47) [2].
There's (vo2master) device that can apparently measure it in one breath; there was a video on some swimmer using it on turnaround without much interference with their exercise. $7k though.
yeah that's a ridiculous amount. I'd be so jittery there's no way I'd be able to workout after taking that much. If I have more than one cup of coffee in a single sitting I get so anxious I can't even take proper deep breaths.
Reading this article I'm a little confused by the author's conflation of brain energy and the energy expenditure of the body as a whole. In the beginning they mention:
> "Your brain consumes roughly 20 to 25% of your body's total energy at rest"
while later they say:
> "Even chess grandmasters, who sit for hours in states of intense concentration, burn only about 1.67 calories per minute while playing, compared to 1.53 calories per minute at rest"
That second figure seems to refer to whole-body expenditure, not just the brain. And intense cognitive work doesn't happen in a metabolic vacuum - there's increased cerebral blood flow, elevated sympathetic nervous system activity, changes in heart rate variability, hormonal shifts (cortisol, adrenaline). These all have systemic metabolic costs that go beyond the glucose the neurons themselves consume. So the "it's just a banana and a half" framing might be undercounting by quietly switching between brain-only and whole-body measurements.
Also somewhat related - the link to businessinsider about chess grandmasters is broken, but another very interesting rabbit hole here is how energy expenditure is actually measured. A lot of what consumer devices and even many studies report is based on proxy biomarkers like heart rate, HRV, weight, age, and sex, run through linear regression models. True calorimetry (indirect via gas exchange, or direct in a metabolic chamber) is expensive and impractical outside lab settings. That means the precise calorie figures cited with such confidence - the "100 to 200 extra calories" from a day of thinking, or the per-minute burn rates of chess grandmasters - likely carry wider error bars than the article suggests. We don't really have a great way to measure real-world energy expenditure accurately at the individual level, which makes me a bit cautious about the neat narrative of "thinking is calorically cheap, full stop."
That said, the core point about adenosine accumulation and perceived exertion affecting training quality is fascinating and well-supported — that part of the article is genuinely useful regardless of the calorie accounting.
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