Dizziness is a term that is often used to describe 2 different symptoms: lightheadedness and vertigo.
Lightheadedness​:​ is a feeling that you might faint.
Vertigo​:​ is a feeling that you are spinning or moving, or that the world is spinning around you. See also: Vertigo-associated disorders

Most causes of dizziness are not serious, and they either quickly get better on their own or are easy to treat.

Lightheadedness occurs when your brain does not get enough blood. This may occur if:

  • You have a sudden drop in blood pressure.
  • Your body does not have enough water (is dehydrated) because of vomiting, diarrhea, fever, and other conditions.
  • You get up too quickly after sitting or lying down (this is more common in older people).
  • ​L​ightheadedness may also occur if you have the flu, low blood sugar, a cold, or allergies.

More serious conditions that can lead to light-headedness include:

  • Heart problems, such as a heart attack or abnormal heart beat
  • Stroke
  • Bleeding inside the body
  • Shock (extreme drop in blood pressure)

If any of these serious disorders are present, you will usually also have symptoms like chest pain, a feeling of a racing heart, loss of speech, change in vision, or other symptoms.

Vertigo may be due to:
Benign positional vertigo, a spinning feeling that occurs when you move your head
Labyrinthitis, a viral infection of the inner ear that usually follows a cold or flu
Meniere’s disease, a common inner ear problem

Other causes of lightheadedness or vertigo may include:

  • Use of certain medicines
  • Stroke
  • Multiple sclerosis
  • Seizures
  • Brain tumor
  • Bleeding in the brain