Hearing loss is not the only factor. Long duration in high noise environments can also cause stress. In the 80's I made a significant number of eight to ten hour rides from the Big Bend area to Houston, chasing tail.
Usually upon arrival I'd find myself all wired up and had trouble calming down, sleeping, etc. Like being jacked up on caffeine, or a six pack of Jolt Cola.
Then I read an article some motorcycle rag had written about testing for the noise level inside a full-face helmet, visor down, at highway speeds. It was something in the neighborhood of 120 db IIRC. The article stated that in a work environment OSHA would require an employee have hearing protection for exposure of greater than five to ten minutes, and that permanent hearing loss could result from extended exposure to these levels.
She-ite, I've been spending hours upon hours in this noisy environ. Yikes!
This was a wake-up call. I then had my hearing tested and discovered that my hearing was impaired.
This prompted me to start wearing ear plugs on every ride, making the same trips, and the difference was amazing. Both in lower noise levels, and in lower anxiety levels (which affect attentiveness while riding) as an effect of hours of being in the noise.
My hearing is still affected, especially noticed in crowded noisy places where I have difficulty following the conversations of those beside me. I occasionally have an episode of Tinnitus, but it rarely lasts very long.
Ear plugs have been a part of my mandatory gear for almost thirty years now. Looking back I wish it had been more like forty or forty five years of riding with ear plugs.
I'm hoping that the Tinnitus I occasionally experience does not get worse.
Hearing loss and noise induced stress are credible factors in the risks motorcyclists face following our passion. These risks can be mitigated. Knowing this and taking steps to prevent it before damage occurs will always be better than stop-gap measures after the damage is done.