I thought this was a thing, that the expression "little death" refers to sleep and suggests that time spent sleeping is time not used for something else; one is, in a way, dead while asleep. Apparently, that's not what the expression stands for; I'm not sure where I got that.

So is there an alternative expression that would convey the idea of sleep as something to be avoided because time could be better used ?

I thought this was a thing, that the expression "little death" refers to sleep and suggests that time spent sleeping is time not used for something else; one is, in a way, dead while asleep. Apparently, that's not what the expression stands for; I'm not sure where I got that.

So is there an alternative expression that would convey the idea of sleep as something to be kept to a minimum because time could be better used ?