I don't necessarily doubt the author, but how do you chronically deprive your brain of glucose?
Afaik you would get glucose back whenever you ate anything. Unless you were doing keto, but then your body and brain run on ketones. And if you did somehow deprive your brain of fuel, you would get symptoms in a much shorter span.
Maybe undereating, but he doesn't list weight loss, and if you're rapidly losing weight and start to notice these symptoms it would seem pretty obvious to try eating more.
It seems very much like confirmation bias. The state of the art of research on FND might be ahead of wikipedia, but it states under 'causes' only this:
> A systematic review found that stressful life events and childhood neglect were significantly more common in patients with FND than the general population, although many patients (around 70%) report no stressors.
https://en.wikipedia.org/wiki/Functional_neurologic_disorder...
With you on this. There is no diagnostic test for glucose/dopamine depletion, and it is unlikely theory in my opinion. Even when you haven't eaten the circulatory system keeps the brain flushed with glucose from the liver or muscle glycogen, and then ketone bodies from ketogenesis. Unless you have a constant flow of these nutrients supported by a normal blood pressure, you pass out quickly. I don't think it's a surprise that he started to improve when he started antidepressants, started seeing a therapist (the psychologist), started exercising more, and took a less stressful job. To me it sounds like anxiety that built up repeatedly after 30 minutes of working. He states that he felt a numb nothingness (anhedonia), had trouble concentrating, and had psychomotor slowing. Only needs one more to hit the criteria for major depressive disorder, and I'm guessing he was having trouble sleeping at this time. From what he wrote ("It was a physical issue.") it looks like he was going to search until he found a non-psychiatric diagnosis, seeking out a neuro-psychologist (someone with likely no biochem/physiology background), to propose a theory about something that is unlikely.
Regarding the post up above about a TIA (thank you for sharing this story) or the one below about the Microsoft engineer who had neck pain and then a stroke (carotid or vertebral artery dissection, often caused in younger people by car crashes or neck manipulation by a chiropractor..), I think a TIA/stroke is much less likely in this guy's case because of the recurrence of the symptoms after being able to work for a period of time. Someone who's had a TIA hitting Broca's area (motor speech) won't be able to work for a little and then have to stop, they're just not going to be able to speak/type. And unless they're very unlucky they're not going to have them repeatedly only after working for a short period of time. Maybe it is an exact match with the TIA post above with anxiety/PTSD after the initial TIA with word finding difficulty, but it doesn't seem like this guy had word finding difficulty at first because he was able to work after sleeping off his stroke.
If you want to run with glucose, he could have type I diabetes or an insulinoma if you want to go rare, but the symptoms are going to be resolved immediately after eating anything with carbs.
But what do I know, just a student in the American medical system.
The brain actually burns a lot of energy so I think its not unreasonable to expect it to burn the fuel it has access to. There was this study on chess players or something in a competition, I don't remember what the study was called exactly, but they found the chess players despite sitting down the whole time burnt an extraordinary amount of calories.
In China there is even sort of a common saying for this. Generally when someone starts sort of acting stupid or in a daze its commonly related to, half jokingly, as “低血糖” or "low blood sugar"
There are tons of psychological and physiological mechanisms that would activate before reaching literally 0g of glucose if your brain, most that would send you straight into the ER or into complete loss of consciousness.
Dangerously low blood sugar doesn't cause losing the ability to speak or to function that you can ignore and just keep working.
I might be wrong but I dont think the brain actually expends 'more' energy in intensive cognitive tasks in the way you suggest.
"As Harrington explained, "The brain is able to shunt blood [and thus energy] to particular regions that are being active at that point. But the overall energy availability in the brain is thought to be constant." So, while there might be significant spikes in energy use at localized regions of the brain when we perform difficult cognitive tasks, when it comes to the whole brain's energy budget overall, these activities don’t significantly alter it."
"Elite chess players are under intense pressure that causes stress, which can lead to an elevated heart rate, faster breathing and sweating. Combined, these effects burn calories over time."
I'm not an expert but it does seem incorrect. As I understand it (correct me if I am wrong), the brain cannot function alone on ketone bodies and always needs some glucose. Even when fully depleted and in deep ketosis, the liver will synthesize glucose via gluconeogenesis.
People usually get "hangry" / feeling like they're going to die like a diabetic does before entering a coma if their glucose actually crashes. My dad was an adult-onset type-1 from exposure to Agent Orange who ended-up in the hospital more than once from either insulin misadministration or glucose-management issues.
They might've actually had something like a nervous breakdown or a TIA.
PSA: Don't self-diagnose, esp. if you're not an MD. 99% of the time, you'll be wrong.
It isn't my intention to doubt Tinker, only to continue discourse here, but I was going to say something similar. I have reactive hypoglycemia and it is very, very obvious when my blood sugars are too low - it really is an absolutely horrible thing.
At first I start to feel a little bit "stupid", like my brain isn't functioning properly, and is working in slow motion. Talking is more difficult. Next I start to feel a bit weak/shaky/trembly. Next I start to feel anxiety/dread. Sometimes now I can get very aggressive (which isn't in my nature at all!). Then comes an incredible desire to eat sweet things - once you start eating, it can actually be difficult to stop! Depending on how bad things got, I might feel too confused to actually just go and eat something.
Now, all being well, I did eat something, and will start to feel a lot better within 10-15 minutes.
If I didn't eat something (because there wasn't anything available, or because the "stupid" feeling had given in to confusion, and I didn't know wtf was happening), everything ramps up - the anxiety becomes full on dread, the world seems to be caving in on me, and I literally feel like I'm going to die. The weakness feels like I need to lie down (a couple of times I have, but thankfully my partner was at home and found me). The "stupid" feeling gets much worse - my speech is slurred, and finding the right words to talk is very difficult - mostly what comes out it is "umm.. err.. what?.. uhh..".
T1D here, and you explained the experience of hypoglycemia very well. This is very close to what I get as well.
> Then comes an incredible desire to eat sweet things - once you start eating, it can actually be difficult to stop!
This sucks a lot with diabetes. The survival mechanism kicks in and tells you "eat something, anything, everything", which can subsequently cause your blood sugar to skyrocket, which you then have to correct with more insulin...it can send you on a blood sugar roller coaster than can ruin your entire day. Diabetes sucks.
Yeap. There were blood sugar test strips and lancets in every nook and cranny of the house. Yo-yoing all over the place and developed a phobia about going anywhere in-case "something happened."
My dad was using low blood sugar as an excuse and insulin as an enabler to eat crap, and gained a lot of weight.
He eventually got an insulin pump and cut down on simple carbs.
Diabetes, especially T1 diabetes, is so unbelievably mentally taxing. It's a constant source of cognitive load and stress, as your conscious brain is being forced to take on the functions of your pancreas. A lot of diabetics develop mental health issues and unhealthy habits as a result of it (which is what it sounds like happened to your dad).
For me, a CGM was the biggest game changer, by far. Second was cutting down to eating one (larger) meal per day.
I'm not diabetic but I know what low blood sugar feels like from both exercise depletion and long-term fasting.
If you're not diabetic and have low blood sugar from exertion, just stop what you're doing and drink some water and rest. Your body will handle it just fine. Carbs should be reserved for real emergencies.
Insulin lowers blood sugar, rather than raising it. For T1s, I would imagine an insulin pump would help prevent mistakes where you misjudge how much insulin you need - but I'm not a T1, so can't comment on real-world effectiveness.
In my particular situation, the best way to manage things has been to go keto - any more than around 5g of carbs causes me to have a hypo, presumably because my body over-compensates and releases too much insulin. I switched to keto a few years back, and my life has been so much easier since then - I went from having a hypo multiple times a day, to very rarely. It's been several months since my last one.
If I hypo (or in the more general case when a T1 takes too much insulin by mistake and hypos), the "healthier" option is to use glucose tablets or a glucogel tube (a measured dose of glycogen, often carried by T1s).
But when you're having a hypo, you don't always think clearly - it's fine if you catch it early enough, but otherwise it really is like you're under a magical compulsion to eat as much sugar as you can; I'm not sure there is another experience I can relate it to. And once you eat some carbs, it's 10-15 minutes before you even start to feel better - believe me, you can eat an obscene amount in that time!
Anyone who has been around a type I diabetic knows how quickly the brains shuts down when glucose levels drop. It doesn’t even have to get that low before cognition takes a massive hit.
Exactly this. I'm a type 1 diabetic, and the explanation that this was happening due to "burning out all the glucose in my brain" is bogus. It's not how it works at all, and it's not even close to how it feels.
It sounds like this was the diagnosis he was given. I have done extended water fasts for multiple days and often eat keto (<20g carbs per day). And so I am respectfully doubtful about this diagnosis.
Nevertheless, who knows what combination of medical peculiarities might be involved, so I guess it cannot be ruled out.
My prior assumption would still be that a case of burnout/exhaustion, or micro stroke seems like a more probable explanation.
He writes
> talking to other hackers & infosec folk, they have said they've felt similar symptoms. The brain fog after working too hard & too long.
I really get the feeling that being overworked, not resting enough is the problem. I get the feeling that the work ethics and self-concept of being a hard worker makes it somewhat hard to admit that one is being overworked and thus a medical explanation for breakdown is very welcome for some individuals.
> It sounds like this was the diagnosis he was given.
Not quite. He cites the specific diagnosis the doctor gave him and the associated DSM-5 code, but his extrapolation about dopamine and glucose is not part of that diagnosis. It’s not actually physically possible as he describes it.
I agree with what you wrote, but additionally, one can get glucose deprivation by just starving, for example. I can't imagine a way to deprive just the brain of glucose. In effect, sustained physical activity should also lead to "depriving the brain of glucose".
As long as you have the fat reserves, it's possible to fast for weeks with nothing more than water. As long as you have a functioning liver, your body uses glycogenesis to create enough glucose for your brain to function.
The trick is that your burn rate of glucose might exceed supply rate. Especially if stress conditions or dietary situation results in misbehaving supply, too.
Not to mention getting warning signs and pushing through, which I'll be honest I'm guilty of doing as well (though I never got that far, and mostly it was sleep deprivation)
That does happen, but the body is very good at making sure that levels of blood-glucose are maintained. If it is not, as in the case of diabetes, then very bad things happen. Things like a diabetic coma.
As other commenters have said, absent any extreme weight loss or undiagnosed metabolism disorders like diabetes, there is nearly no chance that glucose burn-out occurred in an otherwise 'healthy' person.
We may all be wrong, or missing some key information, at which point I look forward to the cuhbbyEmu video on it.
But the glucose amount in your brain is more like f(t,x,y,z) + constant . So what happens in those situations is that the variable part gets reduced, but the constant part needed for keeping tissues alive doesn't change.
Afaik you would get glucose back whenever you ate anything. Unless you were doing keto, but then your body and brain run on ketones. And if you did somehow deprive your brain of fuel, you would get symptoms in a much shorter span.
Maybe undereating, but he doesn't list weight loss, and if you're rapidly losing weight and start to notice these symptoms it would seem pretty obvious to try eating more.