Understanding Systolic and Diastolic Numbers

Blood pressure readings always consist of two numbers, for example 120/80 mmHg. The first is systolic pressure — the pressure when the heart pumps blood throughout the body. The second is diastolic pressure — the pressure when the heart rests between two beats.

The unit used is millimeters of mercury (mmHg). Understanding both numbers matters so you do not misread results from a sphygmomanometer, whether manual or digital.

Normal Blood Pressure Table by Age

No single number applies to everyone, but here are the commonly used reference ranges: infants (0-12 months) 75-100/50-70 mmHg; children (1-10 years) 80-110/50-75 mmHg; teens (11-18 years) 90-120/60-80 mmHg; adults (19-40 years) 95-135/60-85 mmHg; adults (41-60 years) 110-145/70-90 mmHg; and seniors (over 60) 110-150/70-90 mmHg.

The American Heart Association states that healthy blood pressure is below 120/80 mmHg. As we age, blood vessels tend to stiffen so blood pressure naturally rises — which is why the normal range for seniors is slightly higher.

When Is It Called Hypertension?

Under the Joint National Committee (JNC) VII classification: normal blood pressure is below 120/80 mmHg; prehypertension 120-139/80-89 mmHg; stage 1 hypertension at 140-159/90-99 mmHg; stage 2 hypertension above 160/100 mmHg; and hypertensive crisis at 180/120 mmHg.

Uncontrolled hypertension raises the risk of heart disease, stroke, and kidney damage. Conversely, blood pressure that is too low (hypotension) can also cause complaints such as dizziness and weakness. Consult a doctor for an accurate interpretation of your readings.

Tips to Keep Blood Pressure Normal

Blood pressure is influenced by many factors: age, diet, physical activity, smoking and alcohol habits, medical conditions such as diabetes and kidney disease, stress levels, and certain medications.

To keep it normal: exercise regularly such as walking or swimming, limit salt intake, eat more fruits and vegetables, quit smoking, manage stress well, and check your blood pressure periodically. If your readings fall outside the normal range, consult a doctor or health facility promptly.