Average pressure perfusing the organs through the cardiac cycle.
Formula: DBP + (SBP − DBP)/3 — StatPearls: Mean Arterial Pressure.
What does mean arterial pressure mean?
Mean Arterial Pressure (MAP) is the average blood pressure in the arteries during a complete cardiac cycle. It is a more clinically meaningful single number than either systolic or diastolic pressure alone because it represents the actual driving force that pushes blood through the capillary beds of every organ in the body.
The formula, DBP + (SBP − DBP) / 3, weights diastolic pressure more heavily because, at a normal resting heart rate, the heart spends approximately two-thirds of each cycle in diastole (the filling phase) and one-third in systole (the ejection phase). At higher heart rates, diastole shortens relative to systole, so this formula becomes less precise, but it remains widely used due to its simplicity.
MAP is particularly important in critical care medicine. The kidneys require a MAP of at least 65–70 mmHg to maintain filtration; below this threshold, acute kidney injury can develop rapidly. The brain has autoregulation that maintains cerebral blood flow over a MAP range of roughly 50–150 mmHg, but this autoregulation fails in some disease states. Guidelines for septic shock management use a MAP ≥ 65 mmHg as a primary resuscitation target.
Chronically elevated MAP, even when systolic pressure alone appears only mildly raised, accelerates arterial stiffening, left ventricular hypertrophy, and atherosclerosis. Many antihypertensive agents are judged partly on their effect on MAP rather than individual components.
Reference ranges
| Category | MAP (mmHg) | Clinical significance |
|---|---|---|
| Critically low | < 60 | Organ perfusion compromised — emergency |
| Low-normal | 60 – 69 | Borderline; may indicate volume depletion |
| Normal | 70 – 100 | Adequate organ perfusion |
| Elevated | 101 – 119 | Consistent with stage 2 hypertension |
| Hypertensive crisis | ≥ 120 | Requires urgent medical attention |
When should you see a doctor?
A MAP consistently above 100 mmHg warrants medical evaluation and likely treatment. If your MAP is below 65 mmHg and you feel faint, dizzy, or unwell, seek immediate medical attention. Isolated high readings after exercise or stress may not be clinically significant, however, persistent elevation warrants investigation for hypertension and its secondary causes.
Frequently asked questions
What is a normal mean arterial pressure?
A normal MAP is generally considered to be between 70 and 100 mmHg. A MAP below 60–65 mmHg is clinically significant because it indicates inadequate perfusion pressure to maintain organ function. In the ICU, a target MAP of at least 65 mmHg is commonly used as a resuscitation endpoint.
How is MAP calculated from blood pressure?
MAP is calculated as: MAP = DBP + (SBP − DBP) / 3. The reason DBP is weighted more heavily is that diastole (the relaxed phase) lasts approximately twice as long as systole in a normal resting heart. This formula gives a good approximation of the time-weighted mean arterial pressure over a full cardiac cycle.
Why is MAP important?
MAP drives blood through the capillary beds of the kidneys, heart, and brain. Unlike systolic or diastolic BP alone, it reflects the net driving force for organ perfusion. Critically ill patients with sepsis or cardiogenic shock are managed to MAP targets rather than individual BP components. Chronically elevated MAP accelerates arterial damage and end-organ dysfunction.