Blood pressure is one of the most basic vital signs that healthcare professionals monitor in hospitals. It measures the force of blood against the walls of the arteries as the heart pumps blood around the body. Blood pressure is recorded as two numbers: the systolic pressure (the higher number) and the diastolic pressure (the lower number). A normal blood pressure reading is usually around 120/80 mmHg, although this can vary based on age, gender, and other factors.