Also known as Orthostatic Hypotension, Postural Hypotension(not to be confused with Hypertension) occurs when the body’s natural process of counteracting low blood pressure is interrupted. There are many things that can cause this to happen, but the most common causes are as follows:
1) Dehydration: When your body becomes dehydrated, it is losing more water than it is consuming. The body’s thirst mechanism is fairly weak, and even under normal conditions, when you begin to feel thirsty, you are already slightly dehydrated. Various causes of dehydration are vomiting, diarrhea, poor fluid intake, excessively hot and dry climates that have very low humidity causing your sweat to evaporate almost before it even hits the skin, and strenuous exercise.
2) Heart Problems: There are heart conditions that can lead to a greater risk for Postural Hypotension. These include low heart rate(bradycardia), heart valve defects, cardiac arrest(heart attack), and heart failure. These can all prevent your body from being able to circulate enough blood for your various systems and can cause low blood pressure.
3) Diabetes: Along with many other problems diabetes can cause, Postural Hypotension is another one. Frequent urination can accompany untreated diabetes, as the body attempts to regulate the amount of sugar in the bloodstream by removing it, which can lead to postural hypotension. Diabetes can also cause nerve damage which can wreak havoc on the bodies ability to send signals to help regulate blood pressure.
4) Nervous System Disorders: Parkinson’s disease, Multiple System Atropy(Shy-Drager Syndrome), and amyloidosis can all cause cause problems with the body’s ability to regulate its blood pressure.
Postural Hypotension usually occurs when a person stands up from a seated position, which causes blood to pool in your legs. Blood that normally would be circulating throughout the rest of the body is now stuck in your legs, which decreases the amount of blood circulating back to the heart. The less blood there is for the heart to pump, the lower the blood pressure. Baroreceptors are special cells near your neck and heart arteries that normally can sense this problem, and then cause your heart to beat faster, which causes it to pump more blood, thereby stabilizing your blood pressure. Another special function of these cells is to constrict the blood vessels(make them narrower), which can help increase blood pressure by increasing resistance to blood flow.