with 4 days w/o sleep you would have been hallucinating by the 3rd. and definitely paranoia would already begin to set in, unless of course you were doing meth in which case it probably started months before. you definitely would not have been studying as short time memory is affected big time.
on the other hand if you took lots of 5 and 10 minute naps then you would have made it 4 days. at this time I have been up for 36 six hours due to work. I am actually not sleepy at all and I will have to force myself to sleep. then again I did take several couple of minute naps a few hours ago. after a couple of minutes of sleep you feel wide awake. learned that back in the day when I was in the marines.
longest I have been awake is from friday at 6 am to monday night at about 8 or 9 pm, i had a project that I had to finish by monday morning. I did sleep a total of perhaps 3 or 4 hours. I was paranoid and hallucinating by the time I went to sleep on monday night. 3 weeks later I quit my job as I didnt think the job was worth putting my health at risk.
I am still wide away right now fully functional. so I'll be heading to the store to buy a couple of beers to force myself to sleep. as i will be doing another double from 2pm to 6 am, off saturday and back to work sun from 6 am to 10 pm.
anyway 4 days up w/o caffeine or drugs, kindda doubt it., actually kinda doubt that you would have been able to study or write other than nonsense lol. btw I never finished my project due to by sun night I forgot what i was working on and started working on a different project totally disregarding the first

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semp