Trembling when extremely tired

[237SJ]

Didn`t know whether to put this here or body and soul but I thought it might be more medical science.
When I`m extremely tired I tremble but it`s like an internal trembling. One of my colleagues has a sister-in-law who is a surgeon and she said that one`s internal organs go into a short, temporary resting phase at some point and because I`m awake I feel this. I`m talking about after no sleep for at least 24 hours plus which is a fairly common occurance for my colleagues and I and we all feel this `internal trembling`.
Could this be the reason?

[Answerprancer]

Could be, you mean like a nervous thing ?
I have had something similar when I'm very tired and have just got in from a long night-drive. It's as if one part of me is dog tired but another bit is nervy and awake.
I get a lot of 'sleep-twitches' when I'm like this.
Maybe a 'nightcap' as you say is the solution.

[237SJ]

Don`t know Answerprancer. I`m talking about shifts of 24 hours plus.

[Andyvon]

Something's very wrong if you are having to work shifts of 24 hours plus 237. Perhaps you should consider a more reasonable job.