Why Does Thinking Hard Make You Tired?

After studying or taking a test, do you ever get tired? Why do we get sleepy after thinking hard?


Read More:
The body and the brain: Impact of mental, physical exertion on fatigue development
“Do you ever notice how stress and mental frustration can affect your physical abilities?”

Effects of Mental Fatigue on the Development of Physical Fatigue
“The findings suggest that interference in the prefrontal cortex may influence motor output during tasks that require both physical and cognitive processing.”

Why Does the Brain Need So Much Power?
“It is well established that the brain uses more energy than any other human organ, accounting for up to 20 percent of the body's total haul.”
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[mintunandi]

Not only while taking tests but also after continuously solving 2 hours of simple math calculations i get tired.

[berry]

That explains why I can't read a non-fiction book for more than 30 minutes without practically passing out

[cyshel]

I'm 46, so it's been a long time since I was in school, but I definitely notice something is going on when I do spend time learning! I already do suffer from some fatigue, but when I watch an educational video on PBS, such as Nova, I start to feel really zapped, almost as tired as I am if I am getting sick! I start to fall asleep without even being tired.

[HermosoEcuador]

When I study or get ready for an exam, I get so hungry. Specially the crave for carbs is high! :O

[WordOfTruthTube]

I get mental fatigue when studying, when learning, or when trying new things that require more focus. I will say that if you do not frequently use your brain for high power thinking, or learning, this will happen... I look at the brain like a large muscle that is not worked out as often as your legs for instance. So when you think hard, use memory, or critical think, you get tired or need breaks. I am at home learning, in a large room, with only 2 other family members, so that debunks the breathing theory. Honestly eating an egg helped, which tells me omegas play a role. I personally haven't spent a lot of time learning in my life, so learning hurts the front of my head and exhausts me. I am currently getting better, by merely using phone apps for cognitive function, I am using an app called BRAINHQ. This is helping, as it takes more time to exhaust me. So, just food for thought.

[SajalSaun]

Yeah...so now that's why I feel sleepy while reading and my head pains so much! :(

[brostom]

Thank you for the video Julia. I am tired after every 30 min of study. Therefore I take 5 mins break and get back on it. The pomodoro method has helped me. Also studying with a friend who wants me to pass helps. The brain gets tired tired, bored and distracted fast. It’s natural. I found caféine helps. I also recommend a cat who can be our study friend.

[deepSea__]

Tests are not good. They do not teach creative thinking or what you know. They simply teach what you can remember at a high risk, high pressure, high stressed environment. Test also don't judge on if you are a good guesser. Say you know nothing, but you are a good guesser, you guess on the test, and make an 80. Then the kid who actually studies, but is not good at test and finds them stressful gets a 70 or 60. Why is this? People who are good at guessing do not take the test too seriously and that in return leads them to be more calm and helps them to remember what was taught. But the person who is smart, and studies takes the test to seriously, stresses out, and is under pressure, will forget things, take longer, and will overall be in a bad condition. This is not to say people who are smart won't get good test grades. This is to say people who aren't good test takers can and usually are smart. They just don't like the test.

This is a sad result of many. There is standardized state test that go over everything you and more that you learned. This is also on a timer. So while you are taking the test, your brain is on the next question when trying to solve the first one because the timer. 

As someone with S.A.D, and a hypochondriac and a perfectionist, test suck. When I was younger, I would resent test. They made me feel uncomfortable. I would always think that if I fail this test will effect the rest of my life. I will be considered stupid. I can't get a good job, and so on and so on. I would also be one of the last people to be taking the test. Which because of my social anxiety disorder, would make me feel sick. And why was I the last person? Because I would have to get the answer done and it would have to be perfect before I answer the next one. And I would have all the pressure of "What if I fail?". Usually I would make a good grade. But there is also times in which I failed. I am not able to take test.

One good way to stop this is change the school system completely. We are taught things we are not going to need, not interested in, and not taught things for everyday life. Yet test are more important? This is why our school system is so flawed. When we get into Middle school, that should be the time we choose for the job we want or what we want to learn. Talking to my parents and my grandparents, they still have not used anything they learned in school. (besides reading and basic math, even though they use a calculator not their head). We should be taught math up to middle school for everyone. Along with history, reading and English (or what ever language) along with a different language, and science. But, that should not be the core focus for everyone. Say you want to be a scientist, that should be your core focus, science. Say you want to be an author, then English. We should also change how we teach English. We teach English with books that you don't want to read or they have you right a free response to something. That does teach you how to write, yes, but it is not an effective way, or the best way. 

Then when we take test, it should be one student in a space with no one else. (like I said S.A.D is a terrible thing to have during a test. But test should not be what passes you or makes or breaks you. They should not be what grades you at all. They maybe a good thing to show what you know, if there is no grade to it. 

If you agree, or have different thoughts, state your opinion in a reply. If you have more things that could be done to help our school system also reply. I want to know if people have the same view.

[nappybiscuit]

That reminds me of people with ADHD and the their frontal lobe issues.  They have to concentrate much harder to stay focused because of the lack of dopamine and they leave feeling so tired after a test.

[OliVer-nctm]

That girl didn't even take a bite outta that burger -_-

[Minale__]

Tests make me tired, just thinking about writing one does, because they make me anxious, nervous and stressed out, which generally wears you out after a while. 
Testing someone's "knowledge" in a written test is probably one of the worst forms of indicating if that someone actually learnt something anyway.
 
I'd love to see a video on how stress messes with our memory, btw. I love studying, I love learning new things and there is barely any subject I'm not interested in, but even now, in uni, no matter how prepared I am, at some point my brain just goes "afk" and I just can't think straight anymore. I end up having to "re-teach" myself all the things that my brain, for some reason, suddenly "deleted", until I can continue working . And it's usually the easiest stuff - which makes it even worse, especially when you get the test back and see what you have written. 
Sometimes I could quite literally hit my head on the table for some stuff I wrote on tests - even though I clearly knew the right answer.

[fred]

I'm a mathematician, and on the 4th year of college, and also during my master's, I noticed that whenever I took a test something went really wrong with my entire body: not only I felt dumber on the day and also on the following day, but I lost some dexterity, if I tried to run for example there was a high chance I would fall or injury myself in some way. Also, if I played soccer, or any other sport, I would play really poorly.

[mikolajpatyna]

I remember being in my math class and one of the guys just finished the whole test in like 15 minutes and slept for the rest of the time we had the test for.

[ThrowItOnTheGrill]

I work IT and when there's a crisis and/or I'm pulled into a team, I get exhausted from trying to brainstorm a critical solution. I normally only need four to six hours of sleep per night, tops. After a day of hard thinking, I'll sleep ten hours, no problem. Yes, there's stress related with it, but stress can be a normal part of the day, too.

[BooBaddyBig]

I think a lot of it is muscular tension. In order to be optimally focussed you need to trigger your bodies flight or fight a bit, and that makes you muscles tense, and then they burn calories and make you feel tired. It may well not be your brain being tired much at all; your whole brain is pretty much working all the time anyway.

[ProffesorGreen]

how does the brain and body work during a mixed martial art fight? I'm curious as to what parts of the brain are most active in very technical fighters. For those of you that have never experienced it, it's one of the most taxing things on your body and your mind is either going a mile a minute thinking so to speak or it's completely relaxed and totally reactive it seems.

[bubby]

I was on the Quiz Bowl team my senior year of high school. One tournament I had to play five ~30 min rounds in a row. I was supposed to sit the fourth one out but there was a mix up that would have given my team an unfair advantage should I have. I was so tired that I was pretty much useless in the fifth and the second half of the sixth round.

[aloeterranourishments]

AmazingVideo! I really feel exhausted after I research 4 hours, and I am not after doing physical activity for the same amount of time!

[mscdreams]

i have noticed many times when i eat food and directly start studying or watching tv or videos on laptop i fall asleep. but after taking that nap, when that heaviness in mind dissolves, i feel fresh and relaxed for 1hour. so i think that mind uses our energy which we get from food and when all the energy is used by brain, we get tired but there should be more solutions other than taking a short nap. because there's one disadvantage of short nap too. after taking short nap we forget the important work or thought process which we were developing in pre nap time. that could make us less creative.

[brostom]

Pomodoro system worked well for me and millions of people. I just want to share.
Taking a nap helped me as well. Stay hydrated and do push ups. :)