I just finished two strenuous weeks of proposal work. My workday steadily lengthened over this period until I was working 17 hours a day. My hours summed to 175 for the two weeks; I receive pay for only 80.
The work grew very tiring. At first I was successful in staving off exhaustion with caffeine. By the second week, caffeine by itself had no effect, and I began experimenting with consuming different proportions of caffeine, sugar, and fat. I discovered that a generous piece of pumpkin cheesecake, washed down with a diet Coke, gave me 45 minutes of lucidity, followed by a blood sugar dive that rendered me a blithering wreck. I used two successive pieces of pumpkin cheesecake to keep myself functioning until 1:00 a.m. on my final evening. I don't vouch for the accuracy or even the coherence of a single line that I wrote that night.
To find a comparable episode of exhaustion, I have to look back to the time of my graduate school qualifying exams at the University of Texas. Owing to a lack of motivation, I began studying for the three days of exams about 24 hours before the first exam. I devoted the day and night to memorizing engineering equations and working through sample questions.
Pulling an "all-nighter" was a deliberate strategy. I had read somewhere that knowledge remained in the brain's short-term memory until mental processes during sleep sorted knowledge into important knowledge and unimportant knowledge. The important knowledge was routed to long-term memory for retention; unimportant knowledge was flushed. As I needed every bit of knowledge I could muster to pass these qualifying exams, I couldn't afford to give my brain the opportunity to throw anything away. (I realize now that you should worry any time that you are trying to use your brain to outsmart your brain.)
I showed up for the first exam bleary-eyed and dizzy with fatigue. I finished the exam by noon and immediately went home to study for the second day's exam. Again I studied all night and showed up the next morning so wobbly that I could barely hold a pencil. I finished the second exam and went home to prepare for the third.
As dawn rose on the third day, I was sitting at my desk reading a chemical kinetics text. Empty king-sized Coke bottles littered the floor. A transcendent feeling came over me that I had achieved complete mastery of all of chemical engineering. In fact, the principles seemed so obvious to me that I marveled that I had spent four undergraduate years studying such childishly simple material.
Still in the grip of this grandiose mental state, I walked to the classroom to take the third exam. I remember stumbling several times along the way from fatigue. I arrived, took my copy of the exam from the proctor, and set to work. I finished in record time, an hour before the noon deadline.
The results? By all rights I should have botched all three qualifying exams because of my lack of preparation and my ridiculous strategy of pulling three consecutive all-nighters. But I ended up passing all of them handily. (Perhaps it would have been better for my character to have suffered bad consequences from my foolishness. At any rate, my lack of motivation proved to be an insurmountable obstacle. I left the university and returned to industry shortly thereafter.)
Sorry to say, I had no similar moment of faux transcendence from my exhaustion last week. All that I experienced was fatigue headaches and the occasional sour stomach from late night candy bars and cheesecake.