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[Physiology](https://durgical.com/en/physiology/) · [Cardiovascular](https://durgical.com/en/physiology/#s-cardio)

# Systolic, diastolic, mean and pulse pressure

- Measurement
- Exam priority: high

Blood pressure has a top number when the heart pushes, a bottom number when it rests, and an average that keeps organs perfused.

Updated 2026-11-01

Also called: Blood pressure, Mean arterial pressure (MAP)

**See it in 3D:** [Ascending aorta](https://durgical.com/en/anatomy/ascending-aorta/) · [Aortic arch](https://durgical.com/en/anatomy/aortic-arch/) · [Brachial artery](https://durgical.com/en/anatomy/brachial-artery/)

## Key points

- Pulse pressure = SBP − DBP (≈ 40 mmHg); it rises with larger stroke volume and stiffer arteries.
- MAP ≈ DBP + ⅓ (SBP − DBP), because diastole lasts longer than systole at rest; normal ≈ 70–100 mmHg.
- MAP = CO × SVR (+ RAP): the two levers are flow and resistance.
- Elderly: stiff aorta → isolated systolic hypertension with a wide pulse pressure.
- Wide pulse pressure: aortic regurgitation, hyperthyroidism, anemia, arteriosclerosis. Narrow: aortic stenosis, tamponade, heart failure, hypovolemia.

## What it is

Arterial pressure swings with each beat between systolic (peak) and diastolic (lowest) values. Pulse pressure is the difference and depends mostly on stroke volume and arterial stiffness. Mean arterial pressure is the time-averaged pressure that drives flow into organs.

## Key facts

- The pressure wave travels faster than the blood itself (≈ 3–15 m/s); it speeds up in stiff arteries.
- Toward the periphery the systolic peak rises and the diastolic falls slightly (pulse amplification), but mean pressure falls only a little until the arterioles.
- The aorta's elastic recoil (Windkessel effect) keeps flow going in diastole.
- A cuff that is too small reads falsely high.

### Cardiac cycle (Wiggers diagram)

**HR** 75/min **Cycle** 800 ms **Systole** ≈ 300 ms **SV** 70 mL **EF** 58%

#### 3. Rapid ejection (≈ 220–330 ms)

Once LV pressure exceeds aortic diastolic pressure (about 80 mmHg) the aortic valve opens and most of the stroke volume leaves. LV and aortic pressures peak (about 120 mmHg).

- **Valves:** aortic open, mitral closed
- **Sound:** none normally (the aortic stenosis murmur is heard here)
- **ECG:** ST segment

- Aorta
- Left ventricle (LV)
- Left atrium (LA)
- LV volume
- ECG
- S1 and S2
- Ventricular systole
- Ventricular diastole
- Valve events (MC, AO, AC, MO)

Follow the aortic pressure trace: peak in ejection, the notch at aortic closure, the slow fall in diastole.

## Equations

**Pulse pressure**PP = SBP − DBP

**SBP**
systolic pressure

**DBP**
diastolic pressure

**Mean arterial pressure (estimate)**MAP ≈ DBP + PP/3

At fast heart rates systole takes a larger share, and MAP moves closer to the arithmetic average.

## Reference values (adult)

| Parameter | Value | Note |
| --- | --- | --- |
| Normal blood pressure |
- Aortic regurgitation: bounding pulses and a wide pulse pressure (high systolic, low diastolic).
- Cardiac tamponade: narrow pulse pressure and pulsus paradoxus (systolic fall > 10 mmHg on inspiration).

## Memory aid

Mean pressure leans toward the bottom number because the heart spends most of its time resting.

## Test yourself

Think of the answer, then tap the question to see it.

## A patient's blood pressure is 150/60 mmHg. What are the pulse pressure and the estimated MAP?

Pulse pressure 90 mmHg; MAP ≈ 60 + 90/3 = 90 mmHg.

## Why does an older person often have a high systolic but normal or low diastolic pressure?

A stiff aorta stores less blood in systole, so systolic pressure rises more, and recoils less in diastole, so diastolic pressure falls: wide pulse pressure.

## Why is pulse pressure narrow in severe hypovolemia?

Stroke volume is small, and sympathetic vasoconstriction keeps diastolic pressure relatively maintained, so the difference between systolic and diastolic narrows.

## Why is MAP not the simple average of systolic and diastolic pressure at rest?

At rest about two thirds of each cycle is diastole, so the time-averaged pressure sits closer to the diastolic value.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/physiology/systolic-diastolic-mean-and-pulse-pressure/)

## See it in 3D

The structures of Durgical's 3D anatomy where it happens.

- [Ascending aorta](https://durgical.com/en/anatomy/ascending-aorta/)
- [Aortic arch](https://durgical.com/en/anatomy/aortic-arch/)
- [Brachial artery](https://durgical.com/en/anatomy/brachial-artery/)

## Related topics

- [Flow, pressure and resistance: Poiseuille and turbulent flow](https://durgical.com/en/physiology/flow-pressure-and-resistance-poiseuille-and-turbulent-flow/)
- [Vascular compliance and capacitance](https://durgical.com/en/physiology/vascular-compliance-and-capacitance/)
- [The baroreceptor reflex](https://durgical.com/en/physiology/the-baroreceptor-reflex/)
- [Physiology of hypertension](https://durgical.com/en/physiology/physiology-of-hypertension/)
- [Cardiac output and what sets it](https://durgical.com/en/physiology/cardiac-output-and-what-sets-it/)

## Related conditions

- [Arterial hypertension](https://durgical.com/en/conditions/arterial-hypertension/)
- [Aortic regurgitation](https://durgical.com/en/conditions/aortic-regurgitation/)
- [Cardiac tamponade](https://durgical.com/en/conditions/cardiac-tamponade/)
- [Aortic Valve Stenosis](https://durgical.com/en/conditions/aortic-valve-stenosis/)

[← All of physiology](https://durgical.com/en/physiology/)

Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.

Sources: [20.2 Blood Flow, Blood Pressure, and Resistance](https://openstax.org/books/anatomy-and-physiology-2e/pages/20-2-blood-flow-blood-pressure-and-resistance) (OpenStax (Rice University), 2022); [Essential Hypertension](https://www.ncbi.nlm.nih.gov/books/NBK539859/) (StatPearls (NCBI Bookshelf), 2025); [Cardiac Tamponade](https://www.ncbi.nlm.nih.gov/books/NBK431090/) (StatPearls (NCBI Bookshelf), 2025); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 15). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/physiology/systolic-diastolic-mean-and-pulse-pressure/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/physiology/systolic-diastolic-mean-and-pulse-pressure/