Everyone has experienced occasional dizziness, that temporary light-headed feeling that makes you feel slightly unsteady. Vertigo is a more severe and intense spinning sensation that can cause nausea and vomiting. Both have a variety of causes but commonly stem from problems in the inner ear. 

What is dizziness? 

Many people say they are dizzy when they feel overwhelmed by emotion, unsteady on their feet, weak, faint or mildly nauseous. Dizziness can be a sensation that happens when signals from the eyes, the inner ear and the body’s positional receptors receive information that conflicts.

A typical example of a situation in which it is almost impossible not to experience dizziness is on a boat in choppy water. The body, the inner ear and the eyes all tell the brain that the body is moving but the mixture of signals cause dizziness, intense nausea and often vomiting, commonly known as sea-sickness.  Dizziness is also used as a general term to describe sensations of vertigo, loss of balance and faintness. 

Vertigo: an extreme form of dizziness 

Vertigo is a severe form of dizziness that makes you feel that either you or the world around you is spinning or moving even when you are still. Two main forms of vertigo are recognised depending on the sensation:

  • Subjective vertigo occurs when you feel that it is your body that is moving and spinning.
  • Objective vertigo occurs when you feel the environment is moving and spinning around your body. Anyone who has spun around several times or who has been on a spinning fairground ride has experienced objective vertigo.

Symptoms of vertigo include disorientation as well as a feeling of motion and you may also feel sick, or actually vomit. It is not uncommon to come out in a cold sweat and for your eyes to become unfocused; some people actually have observable abnormal eye movements. Vertigo can come on quickly and then disappear after a few moments or it can last several hours.

Hearing loss and tinnitus can also accompany vertigo depending on the underlying cause. Someone who is severely affected may have difficulty speaking and even walking. This usually indicates that the vertigo has been caused by a problem with blood flow to and around the brain, and it may even be a sign that a stroke has occurred.

What can cause dizziness?

Having a common cold can bring on dizzy spells as can general nausea. Often people experience motion sickness and dizziness when travelling in a car as well as being on a boat.

More serious causes of dizziness include problems with the heart, low blood pressure, dehydration, anaemia or hyperventilation. Feeling dizzy and light-headed can also occur following severe emotional upset.

Occasional spells of dizziness are usually nothing to worry about but if you find that you feel dizzy most of the time, or have regular attacks with no apparent cause, it is a good idea to have a general check-up with your GP to rule out balance problems, ear or eye problems, or more serious underlying health issues. 

What can cause vertigo? 

Most common causes of vertigo are related to problems with the ear:

  • Benign paroxysmal positional vertigo (BPPV) is the most common type of vertigo. It is usually triggered when you move your head suddenly, or in a particular direction. The fluid in your inner ear can collect hard debris and it is thought that the movement of this debris sends abnormal signals about movement to the brain, causing the sensation of dizziness, movement and spinning.
  • Inner ear inflammation can cause a sudden feeling of vertigo which is often accompanied by hearing loss. The most common underlying causes include:
  • Labyrinthitis, when a viral infection causes inflammation of the labyrinth of the inner ear.
  • Vestibular neuritis, when a viral infection leads to consequent inflammation of the vestibular nerve that leads out of the inner ear.
  • Meniere’s disease can also cause serious bouts of vertigo, which are accompanied by tinnitus (ringing in the ears) and hearing loss. Over time, symptoms can generally worsen because of increasing fluid pressure in the inner ear but there are obvious periods of remission in which symptoms are much less obvious.

More rarely, vertigo can be a symptom of severe migraine, stroke or multiple sclerosis. The sensation of dizziness and movement seems to arise due to disturbances in blood flow in the brain, or to nerve inflammation. Vertigo is part of a range of different effects and diagnosis of these conditions tends to depend more on other defining symptoms.