Work at least keeps me somewhat awake. Over years I have developed some coping strategies, for example when I feel sleepy I open a text file and start writing detailed notes about what I am currently doing and why. That way I can continue to work, because when I fall asleep for a moment and lose the current thread of thought, I just read what I wrote recently and continue. Also, the act of typing, and seeing changes on the screen help to keep me awake.
But once in a while we have a long meeting, often in dark-ish and not well ventilated place, and that is like feeding me sleep pills.