Systolic pressure is the upper number in the record of blood pressure. It is the pressure at the moment the heart contracts and ejects blood into the aorta.
It depends on the strength of the heart and the stiffness of the large arteries. With age the vessels lose elasticity and systolic pressure rises — so in older adults it is precisely this that becomes the main marker of cardiovascular risk.
Reference ranges
Systolic BP (mmHg), by pressure category:
| Normal | < 120 |
| Elevated | 120 – 129 |
| Hypertension stage 1 (ACC/AHA) | 130 – 139 |
| Hypertension stage 2 | ≥ 140 |
| Isolated systolic hypertension | upper ≥ 140 with lower < 90 (often in older adults) |
What an elevated level means
Elevated systolic pressure means the heart and aorta are working under overload. A persistent rise damages the vessels and accelerates atherosclerosis, raising the risk of heart attack, stroke and heart failure.
In older adults isolated systolic hypertension is common — the upper number high, the lower normal or even low; this is a consequence of arterial stiffness and needs treatment.
What a low level means
Low systolic pressure (usually < 90) is most often a normal variant in young and fit people. But a sharp fall accompanies dehydration, blood loss, infections and the use of some medications.
Symptomatic hypotension (weakness, dizziness, fainting) needs attention, especially if the pressure falls on standing.
How the test is done
Systolic is measured with a monitor together with diastolic by the general rules: at rest, seated, the cuff at heart level, 2–3 readings. Repeat and home measurements are important for the diagnosis.
The upper number is not interpreted separately — it is always assessed together with the lower one and in the light of age and overall cardiovascular risk.
What affects the value
- Age and arterial stiffness — raise systolic.
- Salt, excess weight, alcohol — raise it.
- Stress, coffee, exertion — temporarily raise it.
- Aerobic training, weight loss — lower it.
- Dehydration and blood loss — lower it.
- Medications (antihypertensives, diuretics) — lower it.
Assess your heart age
Systolic pressure is a cardiovascular risk factor; assess your heart age:
Frequently asked questions
Why is it specifically the upper number that rises with age?
Over the years the large arteries (primarily the aorta) lose elasticity and "cushion" the pulse wave less well. Because of this, systolic pressure rises while diastolic may even fall — this is how isolated systolic hypertension arises.
Upper high, lower normal — is that hypertension?
Yes, it is isolated systolic hypertension, common in older adults. Despite the normal lower number, a persistently high upper one raises the risk of stroke and heart attack and usually needs treatment.
How far should systolic be lowered?
The target is individual and depends on age and risks; often the guide is below 130–140 mmHg. The specific target and therapy are set by a doctor, taking into account tolerance and coexisting conditions.
Related terms
Sources
- American Heart Association — Understanding Blood Pressure Readings
- 2017 ACC/AHA BP classification (review). NCBI/PMC
- MedlinePlus (NIH) — High Blood Pressure