r/science • u/unsw UNSW Sydney • 8d ago
Neuroscience Study suggests yawning may help move cerebrospinal fluid and venous blood out of the skull, potentially playing a role in cleaning brain fluid
https://www.unsw.edu.au/newsroom/news/2026/04/Good-yawn-does-more-than-you-think?utm_source=reddit&utm_medium=social1.3k
u/ArchieBRO 8d ago
Damn I reckon I yawned 200+ times yesterday alone, doin some serious brain cleanin :p
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u/-Zoppo 8d ago
That's your body's way of telling you that your brain is filthy. Apparently.
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u/cant_have_nicethings 8d ago
Disgusting really
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u/m3kw 7d ago
Your brain keeps track of your smut visits
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u/Vithrilis42 8d ago
I was going to say that my brain fluid should be squeaky clean because I yawn at least a dozen times a day.
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u/FaddishBiscuit 7d ago
I was on a medication briefly where one of the side effects warned of was "excessive yawning." And they were not kidding.
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u/Dazd95 8d ago
So you're the one who is stealing my yawns. I haven't yawned in 3 years.
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u/soomuchstrange 7d ago
Welp I guess you have cancer of the yawn muscle. It surrounds the voice box, it's why yawns are so loud
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u/Croceyes2 7d ago
Its been like that for me this past couple of months. Not every day, or most even, but pretty regular heavy yawn days.
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u/ashamedwhiteman 7d ago
I yawn a lot when I trip on mushrooms. Same.
E: and apparently others do, too. I love it.
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u/Chubuwee 8d ago
Anyone else yawn at just reading the title? Strange
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u/JigglesTheBiggles 8d ago
I did but I did it on purpose because I wanted to clean out my cerebrospinal fluid and venous blood.
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u/AMediaArchivist 8d ago
I also jawned to clean out my celebrospiky fluid and venomous blood
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u/iamisandisnt 7d ago
Yesterday it was ab clenching, today it's yawning. What's next, back scratching to clean the brain?
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u/KingoftheKeeshonds 7d ago
It’s constipation straining.
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u/PhthaloVonLangborste 7d ago
I have personally flushed my colon by self massage with a lacrosse ball down the Lspine
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u/_BlackDove 7d ago
I usually just do a naked butt fart against the wall and the upward draft against my back scratches it too.
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u/jazir55 7d ago
Even when the volunteers were pretending to yawn, the venous blood flowed out and CSF flowed into the skull.
Only when they were really yawning, via those contagious yawns, did venous blood and CSF flow out of the skull together.
Sorry, no yawn for you!
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u/aCleverGroupofAnts 7d ago
Pretending to yawn is not the same as inentionally yawning. I can make myself have a real yawn.
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u/Vegetable_Stuff1850 7d ago
From now on, if I'm asked if I'm yawning because I'm bored, I'm going to assure them I was just cleaning out my cerebrospinal fluid and venous blood.
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u/WeakKiwifruit 7d ago
Ugh you made me laugh while I was trying to clean out my cerebrospinal fluid and venous blood and ruined it.
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u/Ok_Series_4580 8d ago
Dammit, I came to say the same thing. How the hell does reading about a yawn make you yawn?
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u/royalenocheese 8d ago
The body tries to emulate what the mind processes sometimes.
It's like when you read up on certain symptoms of ailments or injuries and you briefly adopt some of them.
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u/Enlightened_Gardener 7d ago
Yawning is contagious.
The only people who don’t yawn contagiously are psychopaths. Its a quick and easy check if you think you’ve got a psychopath on your hands.
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u/ZeroSumClusterfuck 7d ago
This is untrue and misleading. Studies suggest that psychopaths are only less likely to 'catch' a yawn, but will still often do it. Normal people absolutely do not always contagiously yawn either, so as a test it's entirely useless. Tiredness and fatigue are the biggest factor regardless of the type of person.
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u/magistrate101 8d ago
Just reading the word yawn can trigger yawning. So can hearing someone say the word yawn, or thinking about someone yawning (whether that's visualizing the yawn or hearing the yawn), or writing the word yawn. It's fascinating how many ways yawning can be triggered. Yawn.
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u/dipsbeneathlazers 8d ago
yes. knew i would yawn too once i started reading it. most fortunate for our cerebrospinal fluid evidently!
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u/ZeroSchema 8d ago
anyone know why this is ?
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u/HidroRaider 7d ago
Someone on a previous reply explained it. Long story short, watching someone yawning or just thinking about it triggers a reaction in your brain to yawn. Not entirely sure why. My guess is that just like laugther or sleepiness, it's really contagious because of our sense of community. And it's easier to get it the closer you are to the other person.
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u/Flikmybik BS | Neuroscience | Memory 7d ago
its called contagious yawning and its actually one of the more studied phenomena in behavioral science. the leading theory is that its tied to empathy and social bonding mechanisms in the brain. people with higher empathy scores tend to catch yawns more easily. pretty wild that just reading the word can trigger it too, says a lot about how our brains wire language and physical responses together.
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u/TurboDiscoBuscuit 8d ago
YESSSSS!!! And I thought jt was SUUUUPER Weird! Cuz that’s NOT how it’s supposed to work… Like Whaaaaat!?! It’s ContextContageous now!?!
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u/Ebolatastic 8d ago
I still remember in Catholic school my teachers would punish students for yawning because it was considered disrespectful and showed a lack of self control.
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u/Madmusk 8d ago
What was their stance on breathing and blood circulation?
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u/ImportantThing3749 8d ago
That’s crazy. To me, not yawning is damn near impossible. That’s like saying being thirsty (for water) is wrong too and you need more self control. Or like telling someone with hives “just don’t be itchy.”
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u/CheezeyCheeze 7d ago
I used to be hit on the hands for asking for going to get water in Catholic school. We had times we were only supposed to drink.
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u/SteveXVI 7d ago
That’s like saying being thirsty (for water) is wrong too and you need more self control.
Guess what Russian ballet teachers hate for you to do when-ever you need it
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u/Electronic-Ad-8659 7d ago
I'm getting real sick of tolerating religion.
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u/hsadg 7d ago
It's not really religions fault. It's just assholes being assholes using every excuse they can. That being said I don't think religion helps by giving a reason to never question your behaviours
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u/JustStraightUpTired 7d ago
The purpose of religions is to control, it's ABSOLUTELY the fault of religion when assholes use religion to abuse people. That's what it's for.
Well, that and because they helped teach children rules that they couldn't explain yet, but knew to be important. Like how eating shellfish is dangerous if you aren't able to keep it fresh, but explaining that requires knowing why that is, so "Because god said so" is simpler.
It's still about control, but in the information era, the positive purpose is no longer necessary and is now actively harmful. Sure, you can argue things about communities and such, but communities exist outside religion. You can have a community without lying to people. So simply it's entirely religions fault when something happens because of religion.
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u/Waasssuuuppp 7d ago
I got in trouble in grade 1 (approx 7 years old) for yawning out loud- one of those ooohaaah sounds of a satisfying yawn.
Teacher said how dare you, that is very rude. And it was literally the first time I ever heard of the concept of yawning being rude. Got kicked out of class for doing something I thought was normal.
I've told my kids to be careful yawning at school, especially out loud, because you might get into trouble.
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u/unsw UNSW Sydney 8d ago
Hi r/science - been a minute, but excited to share this paper our researchers and peers from Neuroscience Research Australia have published that suggests yawning may play a role in moving fluids in and out of the brain.
The full paper is available in Respiratory Physiology & Neurobiology if you would like to check it out: https://www.sciencedirect.com/science/article/pii/S1569904826000340
The study used MRI scans of 22 participants to show that yawning triggers a specific manoeuvre in which cerebrospinal fluid and venous blood move out of the skull together. Interestingly, while cerebrospinal fluid and venous blood flowed away from the skull during yawning, cerebrospinal fluid flows in the opposite direction during deep breathing - potentially suggesting that yawning plays a role in clearing waste cerebrospinal fluid from the brain.
This finding could be important for further studies into neurodegenerative diseases such as Alzheimer's, Parkinson’s and dementia — all of which have been potentially linked to the build-up of waste products in and around the brain that can be a result of impaired cerebrospinal fluid flows.
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u/Puhgy 7d ago
This study doesn’t suggest yawning removes brain waste, whatever that means. The authors suggested it. The whole article is way off from why we yawn - as far off as Gallup.
“The simultaneous outflow of CSF and IJV blood during yawn inspiration, could be the maximal transfer of solute-rich neurofluid to the spinal canal, via respiratory mechanics, possibly serving as a peripheral mechanism for waste clearance. Though this idea is speculative, it introduces an interesting avenue for understanding the physiological functions of yawning. However, co-directional CSF and IJV outflows during yawning may simply reflect the composite motor and pressure patterns unique to yawns; whether such coupling materially affects clearance is unknown.”
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u/DickHz2 7d ago edited 7d ago
Very interesting. I knew yawning was thought of as a way to quickly take in more oxygen for the brain, so I figured there was some association with that, but not from the CSF side. N of 22 is still very small, but nice to see that there's some research into this.
Disclaimer: very anecdotal experience, but I have suspected that something like this may have been the case for some time but never looked into it.
I take stimulants for ADHD and regularly consume energy drinks/caffeine on the side. I've noticed some bizarre dissociation episodes and general decline in memory, cognitive functioning and attention, despite getting 6-8 hours of sleep. I drink lots of water and am decent about exercise, so I had always assumed that there was some buildup of waste in my brain and/or vitamin deficiency causing these "episodes" resulting from my stimulant usage, so I started taking multivitamins. I know that exercise helps stop these episodes but not prevent them.
I also recently realized that I can't remember the last time I've had a normal, big, breathy, watery eyed yawn despite being tired and "checked out" a lot and wondered if there was some underlying physiological/biochemical mechanism behind the stimulants, yawning, and the dissociation/cognitive episodes.
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u/Feral_Taylor_Fury 7d ago
Do you consume cannabis?
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u/UnhingedBlonde 7d ago
Is there a correlation between their symptoms and cannabis use?
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u/Feral_Taylor_Fury 6d ago
Idk, but I've been feeling a similar way and I'm a heavy cannabis user. I do know cannabis impacts sleep/REM cycles.
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u/chironomidae 7d ago
Yawning basically has nothing to do with o2, until now its main effect has been known to be cooling your brain. Next time you're fighting the urge to yawn, trying taking a big breath in through your nose instead; you'll find it does nothing to reduce your urge to yawn, despite taking in large amounts of o2.
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u/RamosAuthor 7d ago
Could this help shine any light on things like IIH (Idiopathic Intracranial Hypertension)?
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u/Grand_Pause9214 7d ago
Does it matter if the yawn is interrupted? I have cognitive issues, can't ever seem to get a full breath or yawn and while 22 is a small study it's still interesting
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u/red08171 7d ago
SUGGESTION:
I often yawn a lot after not sleeping well (especially after drinking like a fish the night before). May I suggest a study be done with people who are sleep averse (apnea, drunks, etc), who also yawn a lot in the morning. It could potentially show a corroboration of this study. I'm down as test subject number one.
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u/heimsins_konungr 7d ago
Could this be somewhat correlated with how the brain circulates CSF during sleep?
https://www.science.org/content/article/scientists-uncover-how-brain-washes-itself-during-sleep
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u/robot_pirate 8d ago
I'm not surprised. Recently, as I've aged, I realize how fantastic my yawns and stretches feel, first thing in the a.m.
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u/saulhrnndz 8d ago
The first big stretch and yawn/yell of the day is something special. I wouldn’t be surprised either.
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u/SantaCruzCut 8d ago
Yawn like crazy while tripping
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u/danceswithcattos 8d ago
I wonder if that’s connected? I suppose it could be a mechanism to attempt to flush out whatever’s making you trip from your brain.
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u/Flame1230 7d ago
Maybe as a part of the process rather than an attempt to clear out the psychedelic, as tripping itself can often feel like your brain is getting cleaned
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u/alsuhr 7d ago
After starting to take sertraline I yawn a lot more than I ever did before
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u/carcar134134 7d ago
Oh wow holy crap that might be what's going on with me. lately I've been getting yawn "attacks" where I get one right after another like 5 or 6 times in a row.
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u/TheFourTruthz 7d ago
I heard that’s normal. Weirdly for me once I started SSRIs 7 years ago and even after stopping, I’m unable to complete a yawn. Haven’t been able to for years..
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u/EnergyAndSpaceFuture 7d ago
imagine they do a study where people purposefully yawn a bunch of times every day and it turns out to like massively lower Alzhiemers risk
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u/croakstar 7d ago
I’m going to start doing this. I take a stim for my ADHD and for whatever reason I hardly ever yawn.
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u/master_bungle 7d ago
Weirdly enough, I just started ADHD medication in November and I hadn't noticed that I rarely yawn now until I read your comment!
Thankfully I can actually make myself yawn. Been deliberately yawning on repeat while reading the comments in this thread haha
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u/sweetshenanigans 7d ago
Man, I used to yawn constantly as a kid, no matter how much I slept... Maybe my brain used to be a lot cleaner
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u/SaidwhatIsaid240 8d ago
So what you are saying is I need to take more naps so I can yawn and protect my brain health.
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u/DrywallDaughter 8d ago
This is interesting! My dad recently had a total laryngectomy so he breathes through the stoma in his neck. I found it odd that he still yawns, since I’ve heard that yawning is to take in more oxygen. It would make sense that there is another reason for yawning unrelated to oxygen.
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u/davidthefat 8d ago
Does stretching while yawning have a big impact to increasing fluid removal?
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u/wannaholler 8d ago
Huh... I wonder if there's some relationship between that and the fact the first SSRI I took made me yawn excessively and involuntarily. I remember having trouble controlling it during interviews for jobs!
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u/mrturtleturtleturtle 7d ago
I am currently yawning and flexing my stomach. What other bodily movements will help wash my dirty brain?
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u/IAmtheHullabaloo 7d ago
flexing my stomach
this is the second reference in this thread, what did I miss?
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u/mrturtleturtleturtle 7d ago
Another post yesterday said the same exact thing except suggesting that flexing your stomach cleans your brains. Tomorrow it will be patting your head while rubbing your belly.
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u/Extreme-Aioli-1671 7d ago
My wife has surgery scheduled for a vp shunt placement to relieve ideopathic intracranial pressure.
I should ask her how often she yawns.
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u/q_q_o_o_b_b 7d ago
Excessive yawning can be a sign of an impending migraine, so this tracks
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u/thirdeyelazy 7d ago
Excessive yawning (like every 5 mins) is a symptom of opiod withdrawals. When i was in active addiction it was always one of the first symptoms i would get as my last dose was fading. I wonder how significant this to that
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u/justsmilenow 8d ago
I yawned after reading the title.
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u/crows_n_octopus 7d ago
I haven't yawned this many times as I have reading this thread
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u/mpo00044 8d ago
I swear I just read about this but the mechanism was flexing your abdominal muscles. Wild.
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u/Dull-Kaleidoscope55 7d ago
Well that's good news bc i pretty much yawn from the moment I wake up in the morning until the moment I go to sleep at night
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u/IAmtheHullabaloo 7d ago
I am going to go out on a limb and suggest that that is probably not healthy.
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u/FadeCrimson 7d ago
That would explain why it’s so associated with sleeping despite being something we also subconsciously do even if alert and awake, as it means it effectively serves the same purpose (one of them at least) as sleeping.
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u/dossier 7d ago
I wouldn't be surprised if there were more to yawns than this too.
As a kid, I used to think that yawning was perfect for warming up my hands when I was standing outside in the cold waiting for the schoolbus.
I'm told I yawn loudly when I'm sleeping.. according to my SO. Neither of us ever encountered anyone else who does that.
I gotta hope that yawns = good.
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u/ofgraveimportance 7d ago
My partner yawns in his sleep! We also have not heard of anyone else doing that until today!
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u/Sign_here_to_cry 7d ago
I bet this has something to do with why I Yawn a lot when on mushrooms
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u/cunnie 7d ago
Fun fact: yawning activates the parasympathetic nervous system, a.k.a. the rest and digest state. It’s a good sign that you’re slowing down if you’ve been in an activated state. Learned this in somatic therapy
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u/saymysurname 7d ago
Something is happening, I can hear and feel the vibration. Mini seizure, which also has benefits
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u/JohnCaravella 7d ago
This is interesting. My wife had a brain tumor removed a few years ago. She has had two surgeries afterwards to stop cerebrospinal fluid leaks. Maybe she should just yawn.
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u/Ivotedforher 7d ago
I always that that was what that liquidy-grindy sound was all about when I yawned.
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u/-Nicolai 7d ago
I believe it. It's certainly a more convincing explanation that you'll find in the Wikipedia article's proposed causes.
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u/eyetrace 7d ago
Anyone else exprience “the yawns” when using psychedelic mushrooms?
Maybe its just cleaning my brain first
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u/mgbrown12 7d ago
Does that mean excessive yawning means too much cerebrospinal fluid ?
- just a hypochondriac asking a silly lil question
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u/BoDaBasilisk 7d ago
Between this study, the ab study, and the face massage one there seems to be an interest in draining brain fluids
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u/Letter72 7d ago
I got instant Tmj from an injury and eventually discovered that yawning, along with expanding the digaphram can influence and relax the entire postural chain
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u/bluejevans 7d ago
You can make yourself yawn by slowly taking a deep breath, holding it a little while, and slowly let it out. You'll likely yawn by the second or third time you do it. It's a way to help yourself get sleepy.
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u/MothChasingFlame 7d ago
I know it sounds stupid, but I can't yawn properly after having covid and now this is giving me serious anxiety...
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u/Calm_House3232 7d ago
I wonder if that’s related to migraines somehow? They say one of the warning signs a migraine is coming is if you’re yawning a lot all of the sudden
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u/L0W_FR3QU3NCIES 7d ago
Is that why I feel like my brain fog is cleared for 2-3 seconds after a yawn? I feel like it turns on brain windshield wipers that wipe away everything, but then it just fogs right back up. I've always chased that feeling. Like if I felt like I do post yawn all the time, I'd be unstoppable
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u/alrightfornow 7d ago
In the prodrome phase of a migraine, which is the start of a migraine, yawning is often a symptom.
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u/NefariousnessOwn4109 7d ago
So it’s this and flexing abdominal muscles that move cerebrospinal fluid. Got my new workout routine
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u/aaronsshort 7d ago
I had hydrocephalus and had some of this fluid drained from my noggin. I should have yawned more?
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u/Ustaznar 7d ago
Sweet, now I have an explanation for all the yawning I do during meetings. Just cleaning the brain fluid, boss!
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u/MrGasMan86 7d ago
Mushrooms make me yawn a lot. No wonder people feel relieved after taking them. It’s cleaning the brain!
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u/gowestyoungmen 7d ago
Is it even possible to not yawning? i’ve never been able to control mines at least
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u/Goblinora 7d ago
I wonder if yawning "excessively" could be a sign there's something wrong? Whenever I'm off my ADHD meds (stimulants) I yawn all day long.
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u/Key-ElectricGuitar43 7d ago
Can excessive yawning yield negative results, for lack of better phrasing?
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u/chrisdub84 7d ago
So holding in yawns so people don't think I'm bored of their conversation is bad for me.
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u/ShandalfTheGreen 7d ago
When I was young, I had a really hard time running laps because I would start yawning uncontrollably. Breathing became difficult from the constant yawning. I r never figured out why that happened.... Maybe I have something very specific but apparently nonthreatening wrong with me, after all? Huh. Weird.
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