For the last 3 years, I was visiting a cooperative university where you work half of the semester as a regular employee of a company and studying the other half

For the last 3 years, I was visiting a cooperative university where you work half of the semester as a regular employee of a company and studying the other half of the semester. During the theory semester, I was sleeping between 3 to 4 hours on weekdays, leaving home somewhere around 5:40 in the morning and sometimes arriving at home at 8:00 in the evening, eating, and then hitting the gym for one hour. As long as I was able to get some sleep on the train commute, I was actually able to cope with that tiny amount of sleep pretty well, I think. Looking back at that time, it might very have been the most productive I had yet. I felt sooo much better getting up at 4:30 in the morning than I feel now when I get up at 6 or 7 (or even later).