I am a male in his mid 20's.
About 3 years ago, I used to have a job where I was constantly sleep deprived due to long hours. This caused me to have a nasty habit of taking naps in my car, even when I came into work on the weekends. Even on some weekdays, I would be so exhausted to drive home that I would sleep overnight in the car. I would never keep the windows open (even a crack) because I was afraid of people tampering with my car when I would be asleep.
The trouble came during the summertime. I remember on several occasions, I would come into work on the weekends but I would be so exhausted that I would fall asleep in my car for several hours during the afternoon (up to even 6 hours). When I would wake up, I would be covered in sweat and almost gasping for air. I assume this is because the temperature and CO2 levels went up dramatically since the windows were closed and there were no parking spots available outside of direct sunlight. However, every time I woke up I would feel somewhat groggy, but not particularly ill.
Soon afterwards I quit this job and life became more relaxed. However, I have had chronic headaches that started during this initial job and have only gotten worse ever since. These do not feel like migraines; they are more like tension headaches, except it feels like the back of my brain is missing or rotting away. It has really interfered with my ability to think clearly and lucidly. Is it possible that these car naps caused me to have some sort of heat exhaustion damage to my brain? Even if I were extremely exhausted, would my body be alerted out of sleep when the temperature or CO2 level gets too high before any damage to my nervous system begins?
I have been to a neurologist several years ago and he says that eventually the headaches will go away. Instead, they have only become more diffuse, intense, and bothersome.
I realize that this is a strange scenario to be asking, but I am intensely curious about anyone's expert opinion.