The rise in pressure from diastolic to systolic levels (pulse pressure) is thus a reflection of the stroke volume. The diastolic pressure, which is the bottom number, is how much pressure your arteries are under between heartbeats. While average values for arterial pressure could be computed for any given population, there is extensive variation from person to person and even from minute to minute for an individual. Mean arterial pressure (MAP) represents the average pressure of blood in the arteries, that is, the average force driving blood into vessels that serve the tissues. In a healthy individual, the normal systolic pressure is 120 mm Hg while the diastolic pressure is The relationship between blood volume, blood pressure, and blood flow is intuitively obvious. Legal. This means, for example, that if an artery or arteriole constricts to one-half of its original radius, the resistance to flow will increase 16 times. Since pressure in the veins is normally relatively low, for blood to flow back into the heart, the pressure in the atria during atrial diastole must be even lower. In contrast, a high or wide pulse pressure is common in healthy people following strenuous exercise, when their resting pulse pressure of 3040 mm Hg may increase temporarily to 100 mm Hg as stroke volume increases. The length of our blood vessels increases throughout childhood as we grow, of course, but is unchanging in adults under normal physiological circumstances. Lets say you have two pulse pressures, taken five minutes apart, with the first being 42 and the second being 38. Any factor that causes cardiac output to increase, by elevating heart rate or stroke volume or both, will elevate blood pressure and promote blood flow. These pressures are measured in millimeters of mercury (abbreviated mmHg because of the elemental symbol for mercury). The measurement of blood pressure without further specification usually refers to systemic arterial pressure measured at the upper arm. Blood pressure (BP), sometimes referred to as arterial blood pressure, is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs.