We have all heard it said about some people that “noise doesn’t bother them, they can sleep through anything”.  Well, yes and no.  The fact is that, even though a person may not be awakened by loud noise, it still registers in the brain.  Our evolutionary response to loud noise is one of fear and arousal.  When a brain registers loud noise, the nervous system is alerted to possible peril.  As a consequence of these constant nervous responses, our nervous systems become stressed out, and the incidence of heart attacks and high blood pressure rises.  According to one study, people living in noisier neighborhoods have a 17 percent higher risk of cardiovascular disease (including stroke and hypertension).