You might think dehydration just makes you thirsty — but it can also quietly affect your blood pressure. When your body doesn’t have enough water, your blood volume drops. That means your heart has to work harder to pump blood, and your vessels tighten to hold on to what’s left — leading to unpredictable pressure changes. Here’s what happens inside your body: 💧 Your brain releases a hormone called vasopressin that causes your blood vessels to constrict — raising your pressure. 💧 Sodium levels