I can't put any numbers on it, but I'vew had the situation where I wheeled my bike into the garage and wondered what water was running as the rest of the family was out of town before I realised my ears were misbehaving due to the wind noise they'd just been subjected to. It is very infrequent that I get anything that bad, but it's hard to believe that there is not some cumlative damage happening. I've wondered about ear plugs to cut the noise some but worry that may impair hearing traffic sounds too much. All the advise anybody has ever offered is it doesn't happen to them or just turn your head a little, useless.