Health & Fitness
Dizziness is a word that is often used to
describe two different feelings. It is important to
know exactly what you mean when you say "I
feel dizzy," because it can help you and your
doctor narrow down the list of possible problems.
Lightheadedness is a feeling that you are about
to faint or "pass out." Although you may feel
dizzy, you do not feel as though you or your
surroundings are moving. Lightheadedness often
goes away or improves when you lie down. If
lightheadedness gets worse, it can lead to a
feeling of almost fainting or a fainting spell
( syncope). You may sometimes feel nauseated
or vomit when you are lightheaded.
Vertigo is a feeling that you or your surroundings
are moving when there is no actual movement.
You may feel as though you are off balance,
spinning, whirling, falling, or tilting. When you
have severe vertigo , you may feel very nauseated
or vomit. You may have trouble walking or
standing, and you may lose your balance and
fall.
Although dizziness can occur in people of any
age, it is more common among older adults. A
fear of dizziness can cause older adults to limit
their physical and social activities. Dizziness can
also lead to falls and other injuries.
Lightheadedness
It is common to feel lightheaded from time to
time. Brief episodes of lightheadedness are not
usually the result of a serious problem.
Lightheadedness often is caused by a
momentary drop in blood pressure and blood flow
to your head that occurs when you get up too
quickly from a seated or lying position
( orthostatic hypotension ). Ongoing
lightheadedness may mean you have a more
serious problem that needs to be evaluated.
Lightheadedness has many causes, including:
Allergies.
Illnesses such as the flu or colds. Home
treatment of your flu and cold symptoms usually
will relieve lightheadedness.
Vomiting, diarrhea, fevers, and other illnesses
that cause dehydration .
Very deep or rapid breathing ( hyperventilation).
Anxiety and stress .
The use of tobacco, alcohol, or illegal drugs.
A more serious cause of lightheadedness is
bleeding. Most of the time, the location of the
bleeding and the need to seek medical care are
obvious. But sometimes bleeding is not obvious
(occult bleeding). You may have small amounts
of bleeding in your digestive tract over days or
weeks without noticing the bleeding. When this
happens, lightheadedness and fatigue may be the
first noticeable symptoms that you are losing
blood. Heavy menstrual bleeding also can cause
this type of lightheadedness.
Sometimes the cause of lightheadedness is an
abnormal heart rhythm ( arrhythmia), which can
cause fainting spells (syncope). Unexplained
fainting spells need to be evaluated by a doctor.
You can check your heart rate by taking your
pulse .
Many prescription and nonprescription medicines
can cause lightheadedness or vertigo. The
degree of lightheadedness or vertigo that a
medicine causes will vary.
Vertigo
Vertigo occurs when there is conflict between
the signals sent to the brain by various balance-
and position-sensing systems of the body. Your
brain uses input from four sensory systems to
maintain your sense of balance and orientation
to your surroundings.
Vision gives you information about your position
and motion in relationship to the rest of the
world. This is an important part of the balance
mechanism and often overrides information from
the other balance-sensing systems.
Sensory nerves in your joints allow your brain to
keep track of the position of your legs, arms, and
torso. Your body is then automatically able to
make tiny changes in posture that help you
maintain your balance (proprioception).
Skin pressure sensation gives you information
about your body's position and motion in
relationship to gravity.
A portion of the inner ear , called the labyrinth,
which includes the semicircular canals, contains
specialized cells that detect motion and changes
in position. Injury to or diseases of the inner ear
can send false signals to the brain indicating
that the balance mechanism of the inner ear
(labyrinth) detects motion. If these false signals
conflict with signals from the other balance and
positioning centers of the body, vertigo may
occur.
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