Causes of Dizziness

The two types of dizziness, and their causes

Dizzy. Paper Boat Creative/Getty Images

While “dizziness” is a word very commonly used by both doctors and patients, from a medical standpoint it is a very imprecise term. This is because people mean several different things by “dizzy.”

So if you and your doctor want to know why you have dizziness, the first thing you will both have to do is to identify what, exactly, you mean by “dizziness”

The Two Kinds of Dizziness

There are two general kinds of dizziness that produce two distinct kinds of symptoms, and that have entirely different sets of causes.

The two kinds of dizziness are lightheadedness and vertigo.

With lightheadedness, a person feels faint and weak, like they are about to pass out, usually accompanied by an urge to sit down. And if they fight the urge to get down, and attempt to remain upright, they very well might experience syncope (an episode of loss of consciousness).

Vertigo is the sensation that the environment is moving around you when it is not - as if the room is spinning. People with vertigo may feel as if they themselves are whirling and off balance, and they want to grab on to something to keep themselves from being flung to the ground. They may also have nausea or vomiting along with the vertigo.


It is not too unusual for people to experience a brief episode of lightheadedness from time to time, usually when standing up too quickly. These brief episodes are caused by a momentary drop in blood pressure.

The cardiovascular system adjusts to the change in position in a second or two, and the episode passes. Fleeting episodes of lightheadedness when getting up too quickly are generally not a medical concern.

However, if lightheadedness persists or recurs frequently, or if syncope occurs, a medical evaluation is needed.

There are many potential causes of these more serious episodes of lightheadedness, and it is important to figure out the cause.

Some of the more common causes of lightheadedness include:

  • dehydration (for instance, with the flu, with vomiting or diarrhea, or after exercise without adequate fluid replacement)
  • bleeding (which may occur without your knowing it, especially with gastrointestinal bleeding)
  • anxiety or stress
  • the use of alcohol, tobacco or certain drugs
  • various cardiac arrhythmias
  • other cardiac conditions such as heart failure
  • dysautonomia
  • vasovagal syncope

Because the potential causes of lightheadedness are so many and so varied, evaluating patients with this symptom often presents a challenge to doctors. However, because some of the potential causes are dangerous, it is important to make the correct diagnosis.


Vertigo is most often caused by a problem with the inner ear such as an ear infection, but it may also be caused by conditions affecting the brainstem, such as multiple sclerosis or stroke.

Vertigo should always be evaluated by a doctor. If you should have vertigo accompanied by double vision, numbness, tingling or muscle weakness, the probability of a serious neurological problem becomes much higher - and the situation ought to be treated as an emergency. You should get immediate medical help for such episodes.


Tusa RJ. Bedside assessment of the dizzy patient. Neurol Clin 2005; 23:655.

Kerber KA, Brown DL, Lisabeth LD, et al. Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study. Stroke 2006; 37:2484.

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