Working really long hours takes a lot of discipline. While staying awake for so long isn't impossible, it is difficult to ensure high quality for really tight deadlines. In the past I've had to work for a full 20 hours before taking a rest.
I've got a few suggestions that might help people manage to work such long hours.
1. Sit comfortably.
This is obvious and there are lots of great videos on youtube and other websites to help. After working for a few hours it's tempting to squirm around in my chair, but I force myself to keep optimal posture. This seems to work, because I don't seem to get any back problems.
2. Eat heathily.
Don't go drinking sugary drinks to try to get through the night, it's better to keep taking vegetables and whole grains throughout the night. Although sugar gives a quick burst, it will dump you down much quicker after an hour or so. I like to quickly steam some broccoli or something like that. It takes literally 9 minutes, and I can eat and type at the same time.
3. Keep cool.
In a hot country, you may find that the room temperature seems to go up as your deadline approaches. I find that I like to keep the room at a slightly chilly temperature of around 22 - 24 to keep me going through the entire night.
4. Take frequent short breaks.
I usually take a few seconds after every sentence, and maybe stand up after every paragraph for around a minute. After about thirty minutes I go for a quick walk or do something like that for five minutes. I find that if I don't do that, my quality goes down and down as I continue to translate.
5. Don't work long hours!
Obviously the best solution is to plan more reasonable deadlines so you don't have to go through all that in the first place. I find I end up doing a long shift usually if another translator suddenly pulls out without notice, or there's a problem with proof-reading or something.
Those are some suggestions!