Isolated systolic hypertension
Isolated systolic hypertension, abbreviated ISH, is one of the special forms of high blood pressure (hypertension). In the German Hypertension League's classification of blood pressure values, isolated systolic hypertension appears as a further category alongside normal and elevated values.
It is therefore characterized by an isolated increase in the systolic (top) blood pressure value, while the diastolic (bottom) values remain low and within the normal range.
systolic >= 140 mmHg / diastolic < 90 mmHg
Depending on how high the systolic (top) value is, ISH is also divided into three severity grades:
- Grade 1: 140 - 159 (borderline ISH)
- Grade 2: 160 - 179 (manifest ISH)
- Grade 3: ≥ 180 mmHg
If the diastolic (bottom) blood pressure is noticeably low (for example around 60 to 70 mmHg), isolated systolic hypertension carries a particular risk. In this context, the resulting increased pulse pressure should also be noted.
ISH occurs almost exclusively in people aged 55 and older. ISH in under-45s is rare. Women are more likely to show the manifest form.
What causes isolated systolic hypertension?
Two main mechanisms can cause isolated systolic hypertension:
- On the one hand, a malfunction of the aortic valve can cause isolated systolic hypertension. The aortic valve is located at the outlet from the left ventricle to the aortic arch. If this valve does not close properly, blood can flow back toward the heart.
- On the other hand, calcified blood vessels can also lead to this form of hypertension. As the vessels become progressively calcified, they lose their elasticity. This means that the vessels become less and less able to cushion the increase in pressure that occurs when the heart contracts. Studies have found that blood flows back toward the heart in the stiff vessels.
Other causes of ISH can include thyroid disorders or other, less common conditions.
For that reason, isolated systolic hypertension also needs treatment. The doctor should also examine the blood vessels.
Sources:
This article is from Tensana – the leading app since 2011, helping hundreds of thousands of people monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based data and is continuously updated (as of 11/2025).
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.
