I worked in machine shops for over 40 years. I got so used to the machine noise that I would start to fall asleep at lunchtime, lulled by the pulsating hum. And I do have tinnitus.
“I worked in machine shops for over 40 years. “
I trained for the bicycle part of triathlons by riding a bicycle on a highway shoulder for 15 years. I think that’s the culprit in my case.