What Is Orthostatic Hypotension? - Definition, Causes & Treatment

Instructor: Moonjeong Kim
Have you ever gotten a bit lightheaded when getting up quickly from a lying position? Don't worry, most likely, it was both harmless and common. This lesson will define such an experience as orthostatic hypotension; we will explore the definition, causes, and treatment of such bouts of lowered blood pressure.

Dizzy Morning

Have you ever felt slightly dizzy when getting up from bed in the morning? There are actually a lot of different names for such an experience, including 'lightheadedness' or 'a head rush'. Of course, medical professionals have a number of names for it as well, such as 'orthostasis', 'postural hypotension', or the name which we will use for this lesson: 'orthostatic hypotension'.

If you have ever become lightheaded when rising, you also may have noticed that the dizzy spell didn't last long. In fact, chances are you just went on with your day, as if nothing had happened. Which is exactly what you should have done! Mild orthostatic hypotension doesn't usually need treatment. Many people occasionally feel dizzy after standing, and it's usually not cause for concern. Let's take a look at what orthostatic hypotension is and what causes it.

Orthostatic Hypotension

Orthostatic hypotension is when a person feels dizzy or lightheaded when moving from a sitting to standing position, or a laying to sitting or standing position. The dizzy sensation is due to a drop in blood pressure. When a person moves - especially quickly - from a horizontal to a vertical position (such as from lying down to standing up), gravity can affect the blood flow of the body.

Technically speaking, the term 'orthostatic' means 'relating to or caused by standing upright' and 'hypotension' is a word for lowered blood pressure. While you will recognize it as a dizzy spell, a doctor would scientifically recognize it as an instance when your heart rate goes up by 15% or more, and your blood pressure drops by 15 points in systolic pressure and 10 points in diastolic pressure. For instance, if your blood pressure normally reads 120/80, during an episode of orthostatic hypotension, the reading would be 105/70 or lower.

In healthy bodies, the cardiovascular system is able to compensate for the effect of gravity, thereby preventing dizzy spells. When all is working well, as you sit upright, the blood vessels in your legs will constrict, or get tighter, in order to prevent blood from pooling into the legs. Blood volume stays in regions of the body where it was pumping before you got up, which means you do not experience any lightheadedness as your blood pressure drops with gravity.

In some cases, though, blood vessels aren't able to constrict quickly enough and you do get dizzy. The majority of the time, these dizzy spells will last only a few seconds and can be quickly remedied by stillness or laying back down. For some, however, frequent instances of orthostatic hypotension may be an indicator that something else is wrong.

Causes and Treatment

There are a number of causes of orthostatic hypotension, many of which are harmless and easily fixed. Dehydration or a very full stomach are two such causes. Older individuals and pregnant women may experience bouts of orthostatic hypotension more frequently. Even staying in a single position for a long period of time can cause dizziness when you stand up again.

Individuals who experience orthostatic hypotension on a regular basis, however, should be evaluated by a physician. In such cases, underlying causes may include heart problems, disorders associated with the nervous system, or endocrine issues, like diabetes, thyroid conditions, or persistent low blood sugar.

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