There are numerous reasons for dizziness.
Inner ear and balance
Dizziness has many possible causes, including inner ear disturbance, motion sickness and medication effects. Sometimes it's caused by an underlying health condition, such as poor circulation, infection or injury.
The way dizziness makes you feel and your triggers provide clues for possible causes. How long the dizziness lasts and any other symptoms you have also help pinpoint the cause.
Inner ear problems that cause dizziness (vertigo)
Your sense of balance depends on the combined input from the various parts of your sensory system. These include your:
Eyes, which help you determine where your body is in space and how it's moving
Sensory nerves, which send messages to your brain about body movements and positions
Inner ear, which houses sensors that help detect gravity and back-and-forth motion
Vertigo is the false sense that your surroundings are spinning or moving. With inner ear disorders, your brain receives signals from the inner ear that aren't consistent with what your eyes and sensory nerves are receiving. Vertigo is what results as your brain works to sort out the confusion.
Benign paroxysmal positional vertigo (BPPV). This condition causes an intense and brief but false sense that you're spinning or moving. These episodes are triggered by a rapid change in head movement, such as when you turn over in bed, sit up or experience a blow to the head. BPPV is the most common cause of vertigo.
Infection. A viral infection of the vestibular nerve, called vestibular neuritis, can cause intense, constant vertigo. If you also have sudden hearing loss, you may have labyrinthitis.
Meniere's disease. This disease involves the excessive buildup of fluid in your inner ear. It's characterized by sudden episodes of vertigo lasting as long as several hours. You may also experience fluctuating hearing loss, ringing in the ear and the feeling of a plugged ear.
Migraine. People who experience migraines may have episodes of vertigo or other types of dizziness even when they're not having a severe headache. Such vertigo episodes can last minutes to hours and may be associated with headache as well as light and noise sensitivity.
Circulation problems that cause dizziness
You may feel dizzy, faint or off balance if your heart isn't pumping enough blood to your brain. Causes include:
Drop in blood pressure. A dramatic drop in your systolic blood pressure — the higher number in your blood pressure reading — may result in brief lightheadedness or a feeling of faintness. It can occur after sitting up or standing too quickly. This condition is also called orthostatic hypotension.
Poor blood circulation. Conditions such as cardiomyopathy, heart attack, heart arrhythmia and transient ischemic attack could cause dizziness. And a decrease in blood volume may cause inadequate blood flow to your brain or inner ear.
Other causes of dizziness
Neurological conditions. Some neurological disorders — such as Parkinson's disease and multiple sclerosis — can lead to progressive loss of balance.
Medications. Dizziness can be a side effect of certain medications — such as anti-seizure drugs, antidepressants, sedatives and tranquilizers. In particular, blood pressure lowering medications may cause faintness if they lower your blood pressure too much.
Anxiety disorders. Certain anxiety disorders may cause lightheadedness or a woozy feeling often referred to as dizziness. These include panic attacks and a fear of leaving home or being in large, open spaces (agoraphobia).
Low iron levels (anemia). Other signs and symptoms that may occur along with dizziness if you have anemia include fatigue, weakness and pale skin.
Low blood sugar (hypoglycemia). This condition generally occurs in people with diabetes who use insulin. Dizziness (lightheadedness) may be accompanied by sweating and anxiety.
Overheating and dehydration. If you're active in hot weather or if you don't drink enough fluids, you may feel dizzy from overheating (hyperthermia) or from dehydration. This is especially true if you take certain heart medications.