Blood Pressure - What is MAP ?
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That kind of question is exactly the same that I want to make also to the doctor, but I hadn't yet the opportunity in this forum (always displaying the page that there is no room for further questions in the day). I think that you are absolutely right; or the formula is wrong or the reference values are wrong. Even if the formula was (2DP+SP)/3, a normal pressure of 120/80, would give 93,3 mm Hg and that's not in the 80's range.
MEAN ARTERIAL PRESSURE - The average value for arterial pressure. MAP may be calculated using the following equation: [systolic BP + 2(diastolic BP)] / 3
But, also for this formula, I think 80's range is low
MAP = (1/3) (SBP - DBP) + DBP
Here is yet another formula I found.
Extrinsic control of arteriole radius is influenced by neural and hormonal mechanisms, of which activity in the sympathetic nervous systems is the most important. In contrast to localized changes in blood flow caused by intrinsic controls, extrinsic control mechanisms produce widespread changes in arteriolar resistance.
Recall that F = DP / R
This formula can be applied to the entire circulation as for a single vessel, with F being the cardiac output, DP being the mean arterial pressure and R being the total peripheral resistance, most of which is generated in the arteriole system. Thus
Mean arterial pressure = Cardiac output ´ Total peripheral resistance
The total peripheral resistance generated collectively by the arterioles is thus the main factor maintaining mean arterial pressure. In a sense, the arterioles act as a dam, keeping pressure high in the arterial system, so that all tissues can be provided with an adequate blood flow should they demand it.
What is the relationship between a fast heart and BP. My BP is usually low. But my heart rate fluctuates a lot and so does my BP! What does this mean??
Thanks,
Sabrina