Blaring music, incessant traffic, those early-morning lawn mowers — you know they're bad for your sanity, but for your brain? Dr. Mathias Basner, an expert on the effects of noise on health, explains what goes on in your body when it's subjected to prolonged high-decibel exposure, including irreversible hearing loss, cognitive decline, even heart attacks. Fortunately, there are some practical ways to protect yourself — and to reduce your own "noise footprint."