Blood pressure is the measure of how forcefully the heart pumps blood through the vessels. Normal blood pressures can run anywhere from 90/60 to 120/80. A person's blood pressure doesn't remain constant, but varies according to factors such as activity levels, temperature, body position and medications. In most cases, the more serious consequences of low blood pressure depend on its cause. Low blood pressure is often a sign of another condition, such as heart or neurological disorders. It may occur due to severe blood loss, such as from a traumatic injury or gastrointestinal bleed. It may also be due to pregnancy or happen because a person is weak and stays in bed too much. For some people, on the other hand, lower blood pressure is the norm, and it may or may not be consequential.
Chronic Low Blood Pressure
In general, low blood pressure is not cause for alarm. Many people have chronic low blood pressure for years and don't experience any symptoms. For those in this category, no treatment is required, and while their blood pressure should still be monitored, they shouldn't worry about it unnecessarily. Neither should a single low blood pressure reading be cause for alarm, according to the American Heart Association, unless the drop in pressure is significant. However, chronic low blood pressure does occasionally have consequences, according to the Mayo Clinic, including a faint feeling called syncope or dizziness, either of which could lead to injuries from falls.
Very Low Blood Pressure
If blood pressure drops because of an underlying medical condition, a person may experience symptoms such as dehydration, nausea and blurry vision, along with the dizziness and possibly syncope. If a person's blood pressure falls too much, it could lead to shock, a serious medical condition caused by too little oxygen reaching the heart and brain.
Orthostatic Hypotension
Orthostatic hypotension refers to blood pressure that suddenly drops a significant amount when a person changes position, such as going from lying down to sitting, or sitting to standing. Though it usually only lasts a few minutes, it can cause dizziness or even fainting. It's not always clear why people experience this sudden drop in blood pressure, though prolonged bed rest is sometimes the cause. Another specific type, called postprandial orthostatic hypotension, occurs after a meal. Orthostatic hypotension mostly affects older people or those who have high blood pressure or Parkinson's disease, according to the University of Maryland Medical Clinic. Because so many of these people already have balance disorders, they are among the most likely people to fall if they are hit by this sudden drop in blood pressure.
Neurally Mediated Hypotension
Neurally mediated hypotension, like orthostatic hypotension, is a temporary drop in blood pressure. It is more commonly found in children and young adults, however, and occurs when they have been on their feet for quite a while. The symptoms are similar to other conditions where blood pressure drops suddenly, including nausea, dizziness and syncope. Most young people, according to Medline Plus, outgrow this condition.
