Read that a while back, look at the possible explanations, especially tinnitus might be a possibility.

Anyway, I think of it as an interesting phenomenon, it doesn't bother me much (except when trying to fall asleep, once I notice it it is impossible to stop noticing it).

Another thing is that I seem to be "sensitive" to some electronics. For instance, I cannot hold a cell phone to my head for more than a few minutes and I even have to take breaks when listening to music on headphones. The feeling I get bears some similarity to my sleep-deprived state, so I have wondered about a relationship there, if not just a further reduction of my tolerance of electronics.

I can hear the dear foraging around the house at night, and if a car passes on the nearest highway (a few kilometers away) I can hear that clearly too. But during the day all those sounds vanish, masked by the ever present background noise level which is far higher than it is during the night. And my hearing is actually not nearly as good as it used to be.

One simple solution I've found is to play really low volume white noise, that seems to instantly drown out all of it but strangely enough is very hard to detect by itself.

I never noticed any 'sensitivity to electronics'.

But, I also know we lose our high-frequency hearing as we age. I wonder if that somehow increases our sensitivity to the low frequency range.

In any case, I'll have to try the white noise. Seems like it could help with sleep quality, which might in turn reduce sensitivity to it.