evidence: Salt does both. When there's excess salt in your system, the heart pumps more blood in a given time, boosting blood pressure. And over time, salt narrows the vessels themselves, which is the most common "plumbing" feature of high blood pressure. [...] Salt also can threaten the brain by damaging blood vessels and raising blood pressure, which is a major risk factor for stroke. It also might change the behavior of the brain stem, which helps regulate salt balance and blood pressure. [...] Some people who don't have high blood pressure can eat salt without seeing their blood pressure increase. Others may have "salt sensitivity," where even moderate salt intake triggers a higher blood pressure.