I know that these mask the noise, but I wonder if, even though you are not hearing the sound, if it is still penetrating your ears. Not sure if I'm asking the correct question, but it is the noise that causes fatigue and over a long period of time, tinnitus in many people.
Can the noise you are not hearing, cause damage? Is masking really blocking?
No....that isn't how noise cancelling works.
It works by actually cancelling the sound. Sound is waves of pressure pushing and pulling on your eardrum. When a noise cancelling earbud detects a push from outside, it creates a pull of equal strength. The net effect is that neither a push nor a pull makes it to your eardrum. They're not 100% effective, but the amount that is left and the amount added by the noise cancellation that is not offset is a small fraction of the original noise.