What Causes Lightheadedness?

Lightheaded woman
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Lightheadedness is a feeling of faintness as if you are about to black out.

Lightheadedness can occur in distinct episodes, or it can be persistent, and it can be very mild or quite severe. Severe lightheadedness may be accompanied by other symptoms such as sweating, feeling overheated, buzzing in the ears, partial blindness (especially feeling as if you are looking through a tunnel), nausea or vomiting. Lightheadedness usually occurs in the upright position (standing or sitting), and can often be improved by lying down.

Episodes of lightheadedness can be followed by an actual fainting episode, also known as syncope.

Lightheadedness should always be brought to your doctor’s attention, especially if it is recurrent or severe.

Is Lightheadedness the Same as Dizziness?

When people tell their doctor they are dizzy, they usually mean one of two things: either they are experiencing lightheadedness or vertigo. Vertigo, a sensation that the room is spinning, has a different medical significance than lightheadedness.

Another symptom that may be reported to the doctor as dizziness is disequilibrium — a sense of imbalance or unsteadiness that usually occurs when walking. Disequilibrium is most commonly due to problems with the nervous system or the musculoskeletal system. Depending on the cause, it may also be accompanied by actual lightheadedness.

So if you tell your doctor you have had dizziness, you will need to describe as carefully as you can what, exactly, you mean by “dizziness.”

What Causes Lightheadedness?

Lightheadedness can be caused by numerous medical conditions, some of which can be dangerous — this is why you need to tell your doctor if you have this symptom.

Some of the more common causes of lightheadedness include:

How Is Lightheadedness Evaluated?

Because lightheadedness has so many potential causes, and because some of them are serious medical conditions, your doctor will need to do a careful evaluation to sort out the potential causes. In most cases, the cause turns out to be fairly obvious once the doctor focuses his or her attention on the problem.

The most important step in evaluating lightheadedness is to take a careful medical history and do a careful physical examination. It is especially important for the doctor to ask about a history of heart disease, cardiac arrhythmias, or symptoms of palpitations, chest pain, or shortness of breath. Any of these may indicate a cardiac cause, an obvious source of concern. If a heart problem is suspected, the doctor will probably want to do some cardiac testing — certainly an electrocardiogram, and likely an echocardiogram.

However, the most common causes of lightheadedness are dehydration and vasovagal episodes.

The treatment of lightheadedness depends on the underlying cause.

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