What Are Mean Arterial Pressure and Pulse Pressure?

A blood pressure reading gives two numbers, systolic and diastolic, but two more come from them. Mean arterial pressure (MAP) is the average pressure in your arteries over a heartbeat, the pressure that pushes blood into your organs. Pulse pressure is the gap between systolic and diastolic, and it widens as arteries stiffen. Neither replaces the two numbers your blood pressure category is based on, but each says something they don’t on their own.

This article is general information, not medical advice.

Mean Arterial Pressure

Your heart spends about a third of each beat contracting and two-thirds relaxing, so the average pressure sits closer to the diastolic. The usual formula is:

MAP = diastolic + (systolic − diastolic) ÷ 3

For a reading of 120/80 mm Hg, that’s 80 + 40 ÷ 3, about 93 mm Hg. Meaney and colleagues found a factor of 0.412 instead of a third matched measured MAP more closely, but the one-third rule is the one in common use.

MAP is watched closely in hospitals: the Surviving Sepsis Campaign’s guidelines target a MAP of at least 65 mm Hg in septic shock, since below that organs may not get enough blood. For people tracking at home, systolic and diastolic matter more, because guidelines and the evidence behind them are built on those.

A Cuff’s Own Mean Arterial Pressure

Most automatic home cuffs are oscillometric: as the cuff deflates, they sense the pulsations in the artery. The pulsations are largest at the mean arterial pressure, so that’s the one value the cuff measures most directly; systolic and diastolic are then estimated from it by the maker’s algorithm. Some monitors display this measured MAP. It won’t usually match the formula applied to the same reading’s numbers, since the two are different ways of getting at it.

Pulse Pressure

Pulse pressure = systolic − diastolic

At 120/80, it’s 40 mm Hg. With age, large arteries stiffen: systolic tends to rise and diastolic to fall, so the pulse pressure widens. In the Framingham Heart Study, Franklin and colleagues followed 1,924 middle-aged and older adults for 20 years and found that, at any systolic pressure of 120 mm Hg or more, a lower diastolic, and so a wider pulse pressure, came with a higher risk of coronary heart disease. Pulse pressure predicted risk at least as well as systolic or diastolic alone.

There’s no guideline cut-off for pulse pressure in everyday use, though values above 60 mm Hg in older adults are often described as wide. A one-off wide reading means little; one that widens over years is worth discussing with a doctor. A wide pulse pressure can also come from other conditions, such as a leaking aortic valve or an overactive thyroid.

Following It in Kaizora

When you log or import a blood pressure reading, Kaizora derives Mean Arterial Pressure (Calculated) and Pulse Pressure from that one reading’s systolic and diastolic, on the Vitals page. A cuff’s own measured value is a separate metric, Mean Arterial Pressure (Oscillometric), since it’s a different quantity, so the two are never averaged together. Both derived values change at once if you edit the reading. For better readings to start from, see How to Measure Your Blood Pressure at Home, Properly.

The Short Version

• MAP is the average pressure over a heartbeat: diastolic plus a third of the pulse pressure.
• A cuff’s measured MAP and the formula’s differ slightly; both are approximations.
• Pulse pressure is systolic minus diastolic, and widens as arteries stiffen with age.

Sources

• Meaney E et al., “Formula and nomogram for the sphygmomanometric calculation of the mean arterial pressure,” Heart 84, no. 1 (2000): 64. doi:10.1136/heart.84.1.64
• Evans L et al., “Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock 2021,” Critical Care Medicine 49, no. 11 (2021): e1063–e1143. doi:10.1097/CCM.0000000000005337
• Franklin SS et al., “Is pulse pressure useful in predicting risk for coronary heart disease? The Framingham Heart Study,” Circulation 100, no. 4 (1999): 354–360. doi:10.1161/01.CIR.100.4.354