Diastolic blood pressure is the pressure of blood in a person’s arteries when the heart relaxes between beats — the lower of the two numbers in a blood-pressure reading, shown written as the second figure, as in 120/80. While the systolic pressure records the force of the heart’s contraction, the diastolic records the residual pressure in the arterial system during the resting phase, reflecting the resistance of the small blood vessels. Diet influences it through several routes: excess sodium raises it, potassium-rich fruit and vegetables lower it, overweight increases it, and heavy alcohol use pushes it up. Clinicians watch the diastolic figure closely because sustained elevation damages arteries, heart, kidneys, and eyes. It is one of the core vital signs linking everyday eating patterns to long-term cardiovascular risk.