Blood pressure, which is the pressure exerted by blood on the walls of the blood vessels, is calculated by measuring the pressure the circulating blood exerts on the walls of blood vessels during diastole and systole. Diastole and systole are the two phases of the cardiac cycle. The pressure exerted by blood during a diastole and a systole is referred to as diastolic blood pressure and systolic blood pressure respectively. In medical terminology, the difference between the systolic and diastolic blood pressure is referred to as the pulse pressure.
Pulse Pressure = Systolic Pressure - Diastolic Pressure
In case of adults, blood pressure reading is considered to be normal at 120/80 mmHg. Healthy individuals who have a systolic pressure of 120 mmHg and diastolic pressure of 80 mmHg have a pulse pressure of 40 mmHg. The reading would obviously vary for those who have an abnormal blood pressure.
The cardiac cycle refers to the sequence of events that take place when the heart beats. Systole and diastole refer to the two phases of the cardiac activity.
Systolic pressure refers to the pressure that is exerted by blood during the systole, which is the phase during which the heart muscle contracts and pumps blood.
Diastolic pressure is the pressure exerted by the blood during the phase when the heart relaxes and gets filled with blood.
When the difference between the systolic and diastolic pressure becomes quite low, one is said to have a narrow or low pulse pressure. A reading below 25 is considered to be quite low. Though there could be variations in the readings of healthy individuals when they indulge in strenuous physical activities, the pressure reverts to normal after some time.
Resting pulse pressure refers to the difference between the systolic and diastolic blood pressure when one is sitting or not indulging in any significant physical activity. Resting pulse pressure should neither be too low nor too high. If the pressure continues to be remain low, then it would be best to get a thorough medical checkup done. This could be a sign of certain serious medical conditions.
Note: An abnormal pulse pressure cannot be the sole factor while diagnosing one's medical condition. This is due to the fact that a person with an abnormal blood pressure of 140/100 mmHg and a person with an ideal blood pressure of 120/80 mmHg will both have a reading of 40. So, the readings cannot be taken in isolation for the purposes of diagnosing and chalking out a treatment plan.
Generally an increase in the diastolic blood pressure or a decrease in the systolic blood pressure is the contributory factor. Medical conditions that cause abnormal blood pressure could also cause low pulse pressure. The symptoms that one may experience will vary depending on the severity of the medical condition that may be affecting the blood pressure. Some of the possible causes are mentioned below.
- Hypovolemic shock caused due to low blood volume owing to an injury could also affect the readings.
- Aortic stenosis is one such condition that is caused due to the narrowing of the aortic valve. When the aortic valve that controls the flow of blood from the left ventricle to the aorta and to the other parts of the body becomes constricted, sufficient amounts of blood is unable to leave the left ventricle during the systole. This causes lowering of aortic pressure during systole.
- Narrowing of the mitral valve (valve is located between the left atrium and the left ventricle) could also affect the reading. When the blood that moves from the left atrium to the left ventricle during the diastole, is unable to pass freely due to the constricted mitral valve, blood accumulates in the left atrium, thereby increasing the diastolic pressure.
- Cardiac tamponade (compression of the heart due to accumulation of blood in the space between the heart muscle and the pericardium), constrictive pericarditis (long-term inflammation of the pericardium that is characterized by scarring and loss of elasticity of the pericardium), pericardial effusion (accumulation of excessive amounts of fluid in the pericardial cavity), ascites (accumulation of fluid in the peritoneal cavity) and tachycardia (abnormally rapid heartbeat) could also be contributory factors
- High pulse pressure could be caused by conditions such as atherosclerosis (hardening of the arteries), aortic regurgitation, anemia, aortic dissection or hyperthyroidism.
As mentioned earlier, an abnormal reading will be seen in event of fluctuations in one's blood pressure. Since variations in the blood pressure could be caused due to various medical conditions, a timely identification of the underlying disease becomes extremely important. Treating the underlying disease will help in bringing the reading back to normal. Though the treatment of shock, valve disorders, cardiac tamponade, congestive heart failure or a heart attack might involve hospitalization, drug therapy may suffice in case of minor ailments. Those who are suffering from abnormal blood pressure can also check out the alternative healing therapies. Making certain lifestyle-related changes will also prove beneficial. Following a healthy diet and an exercise regime will surely help. Managing stress will also help in normalizing the blood pressure to a great extent.
A narrow pulse pressure indicates a poorly functioning heart. So, if your blood pressure readings are consistently low or high, you must seek medical assistance at the earliest.
Disclaimer: This HealthHearty article is for informative purposes only, and should not be used as a replacement for expert medical advice.