I'm not sure if it's a condition other than exhaustion. After serious coding sessions, I often drive home a little screwy. I've never been in an accident but I defintely put more effort in to staying between the lines, I occasionally have to stop a little bit more quickly than usual because I had trouble gauging the distance to stop in. I just don't drive nearly as fluidly as normal and I've always said that it was because I was very tired. Coding takes a lot of energy and there have been weeks where I put in 5 solid long days and then sleep most of the weekend.
When I'm in the zone, I often end up skipping lunch or I'm very irritated if I have to eat with others, I like to keep focused and think about the problems at hand. It's not that I don't care what is going on in their world, I just don't care at that moment because I've got a job to finish. I also tend to get far deeper in to it than most of the people I work with and the mindset is just different, I'll stop for food and I'm treating it like it was a special forces operation, I put on my black ninja suit and night vision goggles, I go to store or restauruant ("go!!! go!!! go!!! go!!!"), I get the nutritional matter (this is where they blow up the door and storm through before all the pieces hit the ground) , I eat it (shoot the bad guys), I return to my office to finish the job ("clear!!") I don't spend a lot of time making a decision about what to eat or dicking around talking about the weather. I just want the calories and I want them quickly. I'll wolf down one of those fat-hog burritos in 5 minutes.
Sleep also becomes less important. I usually try to get 6-7 hours a night, over the years that number has turned out to be just about optimal, it's not too much and not too little. It's good enough that even on the weekends and vacations I usually get the same amount of sleep, my body just performs better with a regular routine. When I really hit it for a week, and it usually only happens 6-10 times a year, if that much, I'll roll in to the office at 6:30-7:30AM (I like to get stuff done in the AM) and I'll crank until late at night, go home, sleep for maybe 3-5 hours and then repeat. If I do that normally, I'll be burned by Thursday. When I'm hammering though, it Wednesday or Thursday when the rush and high really take hold and I'm usually a mandroid on Thursday and Friday and finish the week strong.. I work out a lot and cycle a bunch and I know about the bonk and the various degrees of it: your tank runs empty and you suffer home to do nothing because your day is shot, it's hard to make it over those last few hills, walking up the stairs in to your appartment might require a rest stop in the middle, once you sit or lie down you will have troulbe getting back up. Then there is the hard bonk, it's when your body's fuel reserves get so low that it starts to defend itself, this is panic mode, you can't think as clearly, you can get tunnel vision, you don't hear things as well, you can have panic attacks and freak out. People do very wierd things when the hard bonk happens, I've heard of people digging through trash to lick the wrappers of food, drinking out of gutters, trying to trade a $3000 bike for a hotdog, doing things they would *never* think to do normally. There is also a time during the hard bonk when you get a surge of energy, doctors don't know why yet but they believe that it's the body's way of putting in one last solid shot to get to safty before major systemic failure. After that surge, you crash, it's just a matter of when and for how long, it might mean not doing anything physical for a couple days, it might mean a trip to the ER and a lengthy hospitol stay (this is very very rare, it is incredibly difficult to work out until you injury yourself that badly.) I kind of think that there is an analog for coding because I abuse the hell out of my body during those week long sessions, I don't eat enough, I don't sleep enough, I definitely don't rest my mind enough and near the end of it I can get really juiced closing in on the goal. Then I crash on the weekend and it might be Wednesday or Thursday of the next week before I can really be really productive again. I've never tried to punch through the weekend yet.