Understanding Low Blood Pressure

Health Professional

Over the last few weeks we've been focusing on high blood pressure and the difficulties this can cause. But, having low blood pressure, or hypotension, can also be problematic.

A normal blood pressure reading is usually in the range of 120/80 (systolic/diastolic); low blood pressure is less than 90/60.

If you're an athlete, low blood pressure is usually a sign of good cardiovascular health. But, in the elderly for example, it may be a sign of an underlying problem. Low blood pressure is however, only a medical concern if it causes signs or symptoms, such as dizziness, fainting, or in extreme cases, shock.

Some of the causes of low blood pressure include:

  • Acute illnesses which leads to severe blood loss or damage to the heart
  • Diseases involving the nerves controlling the veins in the legs
  • Hormonal problems such as an underactive thyroid, overactive thyroid, or diabetes
  • Loss of blood, or loss of fluid
  • Low or high body temperature
  • Blood infection, or anaphylaxis
  • Certain medications - both over-the-counter and prescribed
  • Pregnancy
  • Severe dehydration from vomiting, diarrhea, or fever

There are two types of low blood pressure:** 1. Postural Hypotension** Blood pressure drops when you stand up from a sitting or lying position. Normally, the veins in your legs become narrower when you stand up, forcing blood back to the heart. But, if you have postural hypotension the blood remains in your legs, leading to a lack of blood reaching your brain and the feeling of faintness.

As we age we are in fact more likely to get postural hypotension, because the arteries become less supple, and therefore there is a delayed reaction time. However, it can also be the result of dehydration, lack of food, prolonged standing in high temperatures, amongst other things.

2. Postprandial Hypotension Blood pressure drops following a meal. This may be due to blood pooling in the blood vessels in the stomach as the meal is digested. Other triggers include standing for long periods, and emotions such as fear.

What is the treatment for low blood pressure?

Treatment depends on whether you have postural or postprandial hypotension, and how severe your signs and symptoms are. The goal of treatment is to relieve symptoms and manage any underlying condition causing low blood pressure.

If you have low blood pressure your doctor may recommend some of the following depending on your health status and type of hypotension you have:

  • Try to stand up slowly
  • Don't stand still for long periods of time
  • Ask your doctor about increasing your salt intake
  • Make sure you're getting enough to drink
  • Drink little or no alcohol
  • Eat regular meals, and consume smaller portions
  • Talk to your doctor if you are concerned that medications may be causing your symptoms

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