Hypotension, Direct Opposite of Hypertension

-Ibrahim Suleiman, Ph.D

Hypotension is the direct opposite of hypertension, it means low blood pressure. It is described as having blood pressure much lower than the normal range. It can happen either as a condition on its own or as a symptom of a wide range of conditions. It may not cause symptoms, but when it does, it can require medical attention.

The body has compensatory mechanisms through which it maintains blood pressure within the normal range. Normal blood pressure ranges from 120/80 mmHg to 90/60 mmHg). A blood pressure reading lower than 90 mm Hg for the top number (systolic) or 60 mmHg for the bottom number (diastolic) is generally considered low blood pressure (<90/60 mmHg).

Hypotension may either be absolute or postural (otherwise known as orthostatic hypotension). Absolute hypotension occurs when your blood pressure is sustainably low even while at rest. Postural hypotension occurs when your blood pressure drops within a few minutes of you standing up from a sitting or lying position. It is called postural (or orthostatic) hypotension because it happens with changes in posture. The gravity causes blood to pool in your legs when you stand.

In some people, the blood pressure drops below the normal range within an hour or two hours after eating. This is called postprandial hypotension and it is commonly seen in older adults. What happens is that, after eating, blood flow to the digestive tract increases, in some people this increase becomes sustained, thereby decreasing the total amount of blood in circulation and consequently leading to postprandial hypotension. Eating small, low-carbohydrate meals, drinking more water, and avoiding alcohol might help reduce symptoms of postprandial hypotension.

Depending on its cause, hypotension can affect people of any age and background. Older people are more likely to exhibit symptoms. Younger people commonly show no symptoms. The prevalence of orthostatic hypotension is about 5% for people aged 50 to 70 years and about 30% for people over 70 years old. Absolute hypotension commonly occurs without symptoms; thus it is difficult to establish its overall prevalence.

Symptoms of hypotension happen when your body can’t compensate enough to offset the drop in blood pressure. Such fall in blood pressure may affect blood flow to certain parts of the body, induce unpleasant sensations, and sometimes fetal.

When the brain isn’t getting enough blood supply due to low blood pressure, it elicits common symptoms such as dizziness (or feeling lightheaded), blurred vision, shallow (& fast) breathing, fatigue, weakness, confusion, agitation, fainting (syncope), chest pain (angina), cold pale skin, nausea, and vomiting.

There are various causes of low blood pressure. Loss of blood (hemorrhage), dehydration (e.g. occurring due to spending much time in the sun), and the act of standing up too quickly and without proper compensatory mechanism by the body could result in low blood pressure. During the first and second trimesters of pregnancy, it is possible to experience orthostatic hypotension. Similarly, maternal bleeding can also cause low blood pressure.

Certain disease conditions like Parkinson’s disease have been associated with an increased risk of hypotension. Low blood sugar (hypoglycemia) and sometimes diabetes could cause low blood pressure. Lack of nutrients such as vitamin B-12, folate and iron can keep your body from producing enough red blood cells (anemia), thereby causing low blood pressure.

Life-threatening conditions such as irregular heart rhythms (arrhythmias), blockage within arteries of the lungs (pulmonary embolism), heart attacks, some allergic reactions (anaphylaxis), and some forms of severe infection can also cause hypotension.

Some people develop hypotension after taking drugs that treat high blood pressure, heart failure, erectile dysfunction, depression, and more.

Having low blood pressure without symptoms may not exert harmful effects on you. But if you have symptoms, it can interfere with your ability to stand up, care for yourself, cook, drive and do many other activities. That’s why understanding the condition and following a healthcare provider’s guidance are so important to minimizing this condition’s impact on your life.

If not managed properly, symptomatic hypotension could lead to falls and fall-related injury (e.g. broken bones and concussions). It can also lead to organ damage or shock (shutting down of the body) due to limited blood flow and oxygen.

During hypotension, the heart tries to compensate for the low blood pressure by pumping faster and harder. This can cause heart damage, failure, and likely stroke.

Hypotension is best managed by treating its primary cause. If that cause is treatable directly, hypotension will usually get better on its own. An example of this is hypotension which happens because of an injury and blood loss. Repairing that injury and replacing the lost blood (such as with a blood transfusion) will stop hypotension as long as the repair to the injury holds. If you are on medications that affect your blood pressure, your healthcare provider may change your dosage.

Lifestyle modification may be recommended. These include increasing your salt intake to help increase your blood pressure. Learning to recognize your trigger and symptoms.

In orthostatic hypotension, it is important that someone avoid standing up too quickly. This can help prevent dizziness and fainting due to hypotension. Sit back down the moment you feel dizzy or lightheaded. Falling from standing height can put you at risk for severe or even catastrophic injuries from a fall.

The use of compression socks is also recommended. The socks exert light pressure on your legs and feet, thereby helping with upward pushing of the blood (against gravity) and raising your blood pressure. This is especially recommended for people with orthostatic hypotension. It is also recommended that you adhere to your prescribed medication. You may need to avoid taking recreational drugs or supplements/herbal remedies that can lower your blood pressure.

If you know you have hypotension, you should see your healthcare provider if you start to notice symptoms affecting your life or disrupting your usual routine and activities. Fortunately, this condition is often treatable, and there are many peculiar things your healthcare provider can explain to you that can help you care for yourself.