A loud work environment. A loud work environment that involves the use of power tools, power saws, drills or other noisy equipment may cause temporary bouts of tinnitus. I know of many tinnitus suffers who have attended rock concerts and left with ringing in their ears that may take hours or even days to subside. The longer a person remains in that loud environment, the better their chances will be of developing the condition permanently. These environments can also cause hearing loss. Always wear earplugs when you are in a loud environment, even if it is only going to be for a short time. Mowing the lawn? Wear earplugs.
Atherosclerosis. With age and buildup of cholesterol and other deposits, major blood vessels close to your middle and inner ear lose some of their elasticity — the ability to flex or expand slightly with each heartbeat. That causes blood flow to become more forceful, making it easier for your ear to detect the beats. You can generally hear this type of tinnitus in both ears.