Causes of Low Blood Pressure

By Selena Gerrish

March 4, 2016Conditions & DiseasesNo comments

Low blood pressure, or hypotension is the condition in the heart when the heart is in a relaxed stage. Doctors state that low blood pressure is when the systolic/diastolic value of blood pressure falls below 90/60.

female patient with low blood pressureWhile in some people low blood pressure is a good sign of health, and in some people it is a problem. While in general, it is better to have lower blood pressure, but it can cause problems for patients.

Types of Low Blood Pressure

Depending on the causes and symptoms, low blood pressure can be classified into a few types.

Hypotension due to Nerve Damage

One of the rare disorders, low blood pressure can be caused due to nerve damage, which causes the patient to have very high blood pressure when lying down, and very low blood pressure when standing up. Nerve damage causes abnormality in nervous area responsible for regulating blood pressure.

Neurologically Mediated Hypotension

Due to miscommunication between heart and the brain, young patients often suffer from neurologically mediated hypotension. In this form of low blood pressure, people who are standing for a long time go through fainting, nausea and dizziness.

Hypotension after Eating

This form of low blood pressure occurs in older adults. Hypotension after eating is termed as postprandial hypotension. When you eat food, the blood flow in your digestive tract increases. This increase of blood flow in one area causes a drop in the blood pressure in some individuals (Harvard Heart Letter, 2010).

Hypotension after Standing Up

Hypotension after standing up is termed as orthostatic or postural hypotension. When a person is sitting down, the pressure exerted by the gravity causes the blood to pool in the legs. Orthostatic hypotension causes some individuals to feel dizzy and nauseous when they stand up, as the heart has a hard time supplying blood instantly back to the brain (Low & Tomalia, 2015).

Causes of Low Blood Pressure

Low blood pressure can be caused by a lot of factors. Some of the common factors include the following:

Poor Nutrition

Lack of folates and vitamins in the nutrition can lead to anaemic blood pressure. Anaemia causes a loss in red blood cells, which drops the body’s blood pressure overall.

Severe Allergic Reaction

Severe allergic reaction is termed as anaphylaxis. Caused by latex, venoms, medications or foods, anaphylaxis can cause a drop in the blood pressure along with itching, hives, breathing problems and swollen throat.

Severe Infection

When any kind of infection enters the bloodstream, it can cause infection in the body. This kind of condition can lead to a septic shock, which is a drastic drop in the blood pressure often causing death.

Blood Loss

In case of an injury or internal bleeding, there is a big amount of blood loss. This blood loss can lead to a severe drop in blood pressure as the amount of blood reduces in the body.


Dehydration can cause fatigue, dizziness and weakness. When the dehydration is severe, it can cause the body to go into a hypovolemic shock. This kind of shock causes a decrease in blood volume, which in turn causes a sudden drop in oxygen and pressure within the blood. A person can die within a few minutes or hours if suffering from hypovolemic shock (Zipes, 2010).

Endocrine Problems

Endocrine problems are problems associated with thyroid or endocrinal glands. The levels of hormones in these glands can lead to hypotension. Problems like diabetes, low blood sugar, Addison’s disease and parathyroid disease, all can cause low blood pressure.

Heart Problems

A lot of heart conditions can cause low blood pressure. Heart failure, heart attack, heart valve problems and low heart rate, all lead to a drop in blood pressure. Since there is not enough circulation of blood in the body, there is not enough pressure generation either.


During pregnancy, the circulatory system of a woman can expand rapidly. This expansion can lead to a loss of blood pressure. Drop in blood pressure during pregnancy is normal, and the levels return back to normal after birth.


Medications such as diuretics, alpha blockers, beta blockers, neural drugs including levodopa, antidepressants etc. can all cause a drop in the blood pressure.

Other Blood Pressure Causes

There are a few uncommon causes for low blood pressure that can be detrimental to a person’s health.

Marine Animal Stings

A lot of marine animals bite or sting on accidental contact. For example, bluebottle jellyfish, stingray, corals and anemones all have stingers that release venom into the swimmers. This causes the swimmers to suffer from extreme health conditions; one of which is low blood pressure.

Carbon Monoxide Poisoning

Carbon monoxide is a common gas found in the generators, car engines, grills, heaters and fireplaces. All individuals are exposed to CO gas daily. However, overexposure to this gas can lead to hypotension.

Time of Day and Temperature

Warm temperature can cause blood pressure to drop, as it messes with the regulatory levels of the body. Moreover, blood pressure often tends to be lower in the evening, when your body prepares itself to sleep. It tends to rise during the day and be highest in the middle of the day (Demura, et al., 2008).

Anorexia Nervosa

Anorexia Nervosa is a psychological condition in which the affected person starves himself, thinking he is overweight. Anorexia makes the person vomit if forced to eat more food, causes weight loss, amenorrhea and low blood pressure.

Caffeine Overdose

Drinking too much coffee or excessive intake of caffeine can cause a drop or a sudden increase in the blood pressure. A healthy dosage for coffee is 400mls maximum per day. Any more than that can be detrimental on health. Too much coffee can either lead to hypertension, or it can lead to hypotension, depending on the individual.

There are a lot of causes for low blood pressure. Low blood pressure on its own is never a problem. If your blood pressure drops with an accompanying symptom, only then you need to be worried.


  • Demura, S. et al., 2008. Effects of Room Temperature and Body Position Change on Cerebral Blood Volume and Center-of-foot Pressure in Healthy Young Adults. Journal of Physiological Anthropology, 23(2), pp. 63-70.
  • Harvard Heart Letter, 2010. Eating can cause low blood pressure. s.l.:Gale Group Inc..
  • Low, P. A. & Tomalia, V. A., 2015. Orthostatic Hypotension: Mechanisms, Causes, Management. J Clin Neurol., 11(3), p. 220–226.
  • Zipes, D. P., 2010. Causes of low blood pressure. Saturday Evening Post, September-October, p. 86.
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