Causes of Low Blood Pressure

Covering causes of low blood pressure in pregnancy, in elderly people and after surgery

There are two sides to blood pressure. There is high blood pressure also known as hypertension and then low blood pressure. What causes high blood pressure is not known in the case of essential hypertension. Secondary hypertension is caused by underlying primary medical conditions such as heart disease, diabetes and kidney disease. Treating hypertension is easier when the cause is known and it usually involves a hypertension diet. Low blood pressure, the topic of this article, is also known as hypotension which is abnormally low blood pressure.

Unlike hypertension which is alternatively known as high blood pressure, hypotension is more of a physiological state and less of a disease. It therefore follows that as long as one is not experiencing any of the symptoms of low blood pressure there is no reason for concern. There can however be dangerously low blood pressure levels associated with exceptionally low systolic readings as well as low diastolic blood pressure readings. Unlike hypotension, hypertension symptoms do not show immediately and often does when it's late.

In order to better appreciate causes of low blood pressure readings it is important to know how blood pressure works. The nervous system in a person's body is always continually regulating blood pressure through what is known as the autonomic nervous system. This involves an elaborate extensive network of receptors, hormones and nerves. In the body, blood pressure is raised by the sympathetic nervous system and lowered by the parasympathetic nervous system. The autonomic nervous system is therefore always working to balance the two to achieve normal blood pressure. This is reflected in accurate blood pressure normal readings.

The following is a list of possible causes of low blood pressure [follow link for hypertension causes ];

  • Hormonal changes
  • Side effects of medicines
  • Vasodilation - blood vessel widening
  • Reduced Blood Volume
  • Pregnancy
  • Nutritional deficiencies
  • Underlying Medical conditions

Side effects of medicines as causes of hypotension

Hypertension medications overdose especially of diuretics may also produce low blood pressure. Diuretics are specifically designed to excrete excess water and sodium from the bloodstream bringing high blood pressure in control. When overdone negative results will be experienced which is hypotension. Beta-blockers are yet another class of high blood pressure medications. They may cause low blood pressure by slowing heart rate and antagonizing the pumping ability of the heart muscle. This is the reason why hypertension guidelines are necessary.

Antindepressants and other psychiatric medications have also been linked to a specific type of hypotension called orthostatic hypotension. This is also postural hypotension occurring after a change in physical position. This can be when one stands up from a lying or seated position. The delay by the autonomic nervous system mentioned above to compensate for those changes in blood pressure causes this type of blood pressure.

Reduced blood volume as causes of hypotension

Reduced blood pressure medically known as hypovolemia is mostly associated with hypotension. Blood pressure volume can be reduced by blood loss, dehydration, insufficient fluid intake or fluid loss from other diseases and conditions such as diarrhea and vomiting. In such situations low blood pressure becomes a complication of say continued running stomach or vomiting.

Causes of low blood pressure in pregnancy

hypotension and pregnancyLow blood pressure during pregnancy in women normally occurs at 24 weeks of pregnancy.Fainting and falling due to low blood pressure can be of serious concern. In pregnant women causes of low blood pressure will include dehydration, being very hot and standing for long periods of time.

Pregnancy has the effect of pooling blood in the legs depriving the brain of adequate blood supplies. When this happens standing to your feet usually results in fainting, dizziness or vision blurs. The following are some useful tips for pregnant women. They are not necessarily treatments for low blood pressure.;

  • Drinking lots of water or fluids in general
  • Laying on the side as opposed to back
  • Regular doctor or professional approved exercise
  • Giving self enough time to stand - avoiding rushing when getting up
  • Considering a low blood pressure diet

Vasodilation as a cause of hypotension

Vasodilation is the widening of blood vessels such as large arteries, smaller arterioles and large veins. This plays an important role in lowering blood pressure and is due to the relaxation of what are known as smooth muscle cells within these blood vessel walls. The process of vasolidation is opposite of vasoconstriction which is the narrowing of blood vessels. This effect increases blood pressure. It therefore follows that dilation of arterial blood vessels results in decreased blood pressure.

Causes of low blood pressure after surgery

hypotension surgeryThere are many possible causes of hypotension after surgery. The key ones are loss of blood, heart problems, dehydration, serious allergic reactions, infection and the long lasting effect of anesthetic or pain killers. When referring to specific surgery, low blood pressure is a common side effect of epidural (for pain relief during labor) and spiral anesthesia. Treatment related to surgery that increases blood pressure from a low blood pressure situation would include intravenous fluids, oxygen and other specific medications.

Causes of low blood pressure in elderly people

hypotension elderly peopleThe elderly are susceptible to postprandial hypertension. This occurs after a substantial meal. Blood in great volume is diverted towards the intestines to ensure digestion and absorption of food. The autonomic nervous system may fail to compensate appropriately due to aging or a specific disorder leading to hypotension. This occurs 30 to 75 minutes after a heavy meal.


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