In short - nothing serious. I have not had any regime for many years. About once a week, I spend two nights awake. The maximum I was awake for a week (in fairness, I will make a reservation that during this time I dozed several times for 2 hours somewhere). Of the consequences, after a day and a half of wakefulness, attention begins to be lost, the reaction falls, the desire to sleep (literally, the eyes are closed) alternates with periods of extraordinary vigor, as if you had slept, but literally for a couple of hours, then again. The intellectual load is difficult. After the second day, I advise you to completely avoid making serious decisions, their adequacy will be extremely doubtful, then short-term memory begins to disappear, you forget what happened literally an hour ago, the sense of time is lost. After you still fall asleep, the first time you get up will not get enough sleep, no matter how much you sleep. But then it will pass, after a few hours I usually return to normal. Longest sleep - two days after almost three days of driving without a break
What is harmful and dangerous to lack of sleep? I will tell you from my own experience.
During my life I was lucky to be a student, and not just a student, but a medical student. I know firsthand the sleepless nights trying to frantically master the educational material. My regime was completely lost: when I came home from school, I went to bed, woke up in the late afternoon and studied notes and lectures until morning.
During the test week and session, I forgot what a full sleep is for a In the best case, I managed to get 4-6 hours of sleep, usually it was limited to naps on the way to school and back. At these moments I lived as if on an automatic, not quite understanding what was happening to me. My brain did not understand, I could not even answer basic questions, I forgot the names of my friends and classmates. But surprisingly, in this mode, my memory absorbed information like a sponge, it was enough for me to read the text a couple of times and I could easily quote paragraphs. True, I practically did not keep this information.
During this period of lack of sleep, I could easily forget about eating, I could not navigate in days, weeks and in time, then I did not care much, it was as if I was in the role of the spectator and my personality existed by itself. Somehow, without noticing for myself, I passed the test one by one and I returned to reality only after a full, healthy sleep.
And after such a marathon, I treated my undermined nervous system and stomach. Usually it took me at least a month to recover, or at least just return to the closest possible state from which I started. I was accompanied by constant panic attacks, I was frightened of every rustle, I could be frightened of a "suddenly" appeared person despite the fact that I was expecting his appearance. I was constantly bleeding from the nose, and it alternated with terrible runny nose and nasal congestion. I had a feeling of shortness of breath, from which I wanted to climb the wall (hyperventilation syndrome). I'm not even talking about constant hand tremors, irritation and depression.
It is quite possible that I did something wrong, but I was only enough for 3 courses. And I still feel the consequences of this experience, but 2 years have passed, the nervous system has certainly suffered. Due to the slightest experience, I again have shortness of breath and nasal congestion. Panic attacks sometimes come back to me. I do not know how long it will take to recover, but I will not repeat this again and do not advise anyone. We have only one health and it must be protected, and the desired diploma is not an indicator of education, knowledge and skills. For myself, I decided - you can work on yourself and develop outside the walls of the educational institution)
Good luck to everyone)