Usually when its quiet like before going to bed. Audiologist said it's because of age or caffeine. Please advise me the natural solution.
I expect it's there all the time but you can hear it better when your surroundings are quiet.
Hissing, not hizzing. It's been described as hissing, crackling, static, ringing, like a bell tone and more. It can sound in a variety of ways. It's called tinnitus (TIN-uh-tiss), also pronounced (tin-NYE-tiss). It's the number one most common ear complaint. Whether or not this can be resolved depends largely on the cause. Most cases are idiopathic, meaning no known cause. Other causes are hypernatremia (excess sodium in the blood), hypertension, foreign body in the ear canal, cerumen build up, loud noise exposure, other trauma, some medications, diseases of the inner ear, aneruysms and acoustic tumors. And yes, age and excessive caffeine.
There's no "natural" solution and you'd need to know if yours is even treatable. See an ENT or learn to live with it (which you may have to do anyway).