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I understand that the heart is a pump. The systolic (SYS) one is when it pumps, the diastolic (DIA) one is when it fills with blood again.

Now I think the following holds:

  • SYS of 140 mmHg or more => high blood pressure
  • DIA of 90 mmHg or more => high blood pressure
  • SYS of 90 mmHg or lower => low blood pressure
  • DIA of 60 mmHg or lower => low blood pressure

But this simple rule-set would mean that you could have high and low blood pressure at the same time (I'm not sure if it works from the physics, but it does from the mathematics). For example:

SYS of 140 mmHg and DIA of 60 mmHg

Now I wonder: Is the difference SYS-DIA of significance? What would it mean to have

SYS of 100 and DIA of 80

or

SYS of 135 and DIA of 65
  • I don't understand the relevance of your background section. How does it relate to your question? – Carey Gregory Oct 22 '19 at 3:18
  • @CareyGregory The "After sport" part shows a way higher difference (120 - 44 = 76) than the "normal" one (102 - 60 = 42). At first, I thought that the difference was constant. Currently, I think it might follow a fixed function (which differs by person). Something that mainly depends on size, weight and very recent activity. – Martin Thoma Oct 22 '19 at 5:43
  • And, as I don't have any intuition on how those values should look like, I just thought it was interesting. Measuring them at least for me gives me some idea what a "normal" range might be. – Martin Thoma Oct 22 '19 at 5:44
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    I deleted your background section because I don't think it's relevant to the question and it gives the impression you're asking for personal medical advice. If you disagree, you can revert my edits but I think that will detract from the quality of your question. – Carey Gregory Oct 22 '19 at 21:44
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    As I am new to this community and happy with Jans answer, I'm fine with that :-) Thank you for improving my question :-) – Martin Thoma Oct 23 '19 at 5:22
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Unusual differences between systolic and diastolic pressure may speak for an underlying condition and may be a risk factor for further complications, but can be sometimes normal, for example, in some athletes.

Systolic pressure >140 and diastolic pressure <90 is called isolated systolic hypertension, which can result from peripheral artery disease, heart valve problems, hyperthyroidism, diabetes, etc. (The American Journal of Medicine).

Diastolic pressure >90 and systolic pressure <140 is called isolated diastolic hypertension, which usually results from the hardening of aorta in elderly (Hypertension).

Diastolic pressure <60 and systolic pressure >100 is called isolated diastolic hypotension, which is usually associated with artery hardening in elderly (Hypertension).

Normal diastolic and low systolic pressure is called isolated systolic hypotension, which could result from left heart ventricle failure (Hemodynamics and Cardiology).

Blood pressure changes after exercise:

In healthy individuals, shortly after exercise, both systolic and diastolic pressure tend to drop by about the same extent, as described in the study Post-exercise changes in blood pressure, heart rate and rate pressure product at different exercise intensities in normotensive humans (SciELO):

Most studies dealing with post-exercise blood pressure responses have demonstrated that exercise reduces blood pressure during the recovery period. Nevertheless, the magnitude and the time course of blood pressure changes after exercise are inconsistent.

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Picture: Systolic, mean, and diastolic blood pressures at baseline and after exercise (source: SciELO, Creative Commons License)

Pulse Pressure (NCBI Bookshelf)

Pulse pressure is the difference between systolic and diastolic pressure and is normally about 40 mm Hg (120 - 80 = 40).

Pulse pressure is considered low (narrow), when it is <25% of systolic pressure (for example, 110 - 90 = 20). It can occur in impaired heart muscle function after myocardial infarction or in aortic valve stenosis, for example.

Pulse pressure is considered high (wide), when it is >100 mm Hg (for example, 185 - 80 = 105). It can occur in hardening of the arteries or aorta (mainly in elderly) or in aortic valve insufficiency, for example. Pulse pressure can be also increased in severe blood loss, anemia and hyperthyroidism and, not necessary as a sign of a disease, in some well trained athletes.

| improve this answer | |
  • Great answer but I'm surprised not to see the term "pulse pressure" even mentioned. – Carey Gregory Oct 23 '19 at 4:21
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    I added a section about pulse pressure. – Jan Oct 23 '19 at 10:03

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