Best ways to stay awake as long as possible?

Any doctors here that might know? In a situation like this what is the best way to stay awake as long as possible? You might have to do so in a way that does not amp you up too much though because you in a scenario like this have to PRETEND to be a pod person and act calm and emotionless until you can make an escape and warn the government and military as the hero successfully did in the 1956 version.

Obviously you cannot stay awake forever but I have heard its possible to do so for a week. It might only be possible to stay mentally sharp for a couple of days?

Veronica Cartright had probably been awake for a few days in the final scene of the 1978 version and her judgement was impaired which is why she was stupid enough to approach Matthew like that.