I'd never heard of fan death before!
I have to say though, as soon as I started reading up my first thought was "hmm, dehydration?" - and wikipedia seems to agree with me, stating that reduced hydration makes it harder to control body temperature which consequently leads to hyperthermia.
So, if the night time air temperature is over 30 degrees (unliklely) and the humidity is over 35%, (more likely) turn your fans off, MSIC!