Understanding Blood Pressure
A reading has two numbers, measured in millimeters of mercury. Systolic pressure is the top number and reflects pressure when the heart contracts. Diastolic pressure is the bottom number and reflects pressure between beats.
How it is assessed or used in care
Blood pressure changes with activity, stress, medication, and illness. Correct cuff size, positioning, and a period of quiet rest improve measurement accuracy. Clinicians often use repeated office readings or home monitoring to understand a pattern.
What to discuss with your clinician
Ask your clinician what range is appropriate for you and how to measure at home. Keep a log if recommended. Do not change medication because of one reading without guidance; seek urgent care if a concerning reading accompanies severe symptoms.
Medical references
Sources accessed November 13, 2026.
This information is for general education, not a diagnosis or an individualized treatment plan. Discuss symptoms, test results, and treatment decisions with a qualified clinician. For a medical emergency, call 911.