Is hypotension dangerous? There are several things about hypotension that many people believe to be true, but are actually urban myths. This is an example. It is possible that the medical state of “shock,” in other words, a rapid decline in the blood pressure with decreased function of the body organs ― which can be fatal ― has led to the mistaken belief that low blood pressure (hypotension) is dangerous. In cases of severe blood loss or cardiovascular malfunctions, the blood pressure decreases significantly. However, this is different from chronic hypotension, which is a term describing low blood pressure in a normal person. There is no evidence that chronic hypotension is bad for the health and there are no theories supporting this statement either. Hypotension simply means low blood pressure and there are no criteria that define hypotension. 

Can a person with hypotension suddenly develop hypertension?

A young person with low blood pressure may develop a gradual increase in blood pressure later in life. However, there is evidence that those with hypotension have a lower risk of developing hypertension. There is an urban myth that those with hypotension tend to be weak and have various medical problems, which again has not been proven. A lower blood pressure is still enough to deliver enough blood around the body, so that you could argue that a person with hypotension actually has greater efficiency compared to those with hypertension, who need increased blood pressure to deliver blood around the body.

Postural hypotension, however, which occurs mainly in the elderly, needs to be mentioned. With aging, the ability of the cardiovascular system to change its status rapidly declines. Therefore, a rapid change in posture, for example, standing up from a laying position, can cause a transient decrease in blood pressure, which decreases the blood supply to the brain and therefore causes dizziness. In less severe cases, taking care not to change your position so quickly can be enough to prevent falls and fractures.

Postural Hypotension

Postural hypotension refers to a transient decrease in blood pressure caused when a person stands up, which decreases the blood supply to the brain causing blurred vision or severe dizziness. In severe cases, it can lead to fainting. This is a relatively common condition.

It is natural that blood pools in the lower limbs when a person stands up from a sitting or laying position. The normal response is that the autonomic nervous system, which controls breathing, heart rate, digestion and other functions we take for granted, will cause narrowing of the blood vessels in the lower limb muscles to minimize this effect. As a result, only a drop in pressure of about 10-15 mmHg will occur normally. Several factors can cause a decrease in this response, causing a rapid drop in the blood pressure that then leads to the above-mentioned symptoms. The function of the autonomic nervous system declines generally with aging, and this is the most common cause of postural hypotension. Other causes include alcohol, severe dehydration, or dilated blood vessels in the lower limbs due to sitting in a warm bath for a long time. The most commonly seen cases are those who feel dizzy or experience fainting following a hot bath or shower. People can have severe contusions when they fall, so it is important to be careful of this.

There is no specific treatment for this condition. It is advised that people stand up slowly and sit down or lie down as soon as they feel dizzy to lower the height of their head. If you lean on a wall and wait a while, your reflexes will work to recover the blood flow to the brain and to reverse the symptoms. In severe cases, it can lead to fainting, so it is safest to maintain a lowered posture. Other preventative measures include drinking enough fluids to prevent dehydration and limiting alcohol intake. It is also believed that enough rest and moderate exercise can help. In patients with severe postural hypotension, medication to increase blood pressure can be used. However, the disadvantages of these medications is that they can actually cause hypertension when the person is lying down, and that the medication needs to be taken for life. For these reasons, such medications are not frequently prescribed. If you experience prolonged dizziness or fainting in other situations, or you experience fainting in the toilet, you may have had a “vasovagal syncope” and you should consult a doctor. 

By Sung Ji-dong

The author is a doctor at the cardiac and vascular center/ health promotion center at Samsung Medical Center and an associate professor at the department of internal medicine of Sungkyunkwan University School of Medicine. ― Ed.