Syncope or Fainting
What is fainting?
Fainting is a brief, sudden loss of
consciousness. You become unresponsive, lose muscle tone,
and may fall. Usually, there is complete recovery in a
matter of seconds to a few minutes.
Fainting is fairly common and happens more
often as people get older. The medical term for fainting is
How does it occur?
There are many different reasons for
fainting. Usually fainting is not caused by a serious or
life-threatening medical problem. However, if you are known
to have heart disease, or you faint when you are physically
exerting yourself, the cause may be serious and you may need
prompt medical attention.
One of the most common and least worrisome
reasons for fainting is anxiety or other emotional upset.
The anxiety causes fast breathing (hyperventilation), which
alters your body chemistry enough to cause you to faint.
You may faint if you have not had enough
liquids, especially if you stand up too quickly. This
happens more often after illness or working in the hot sun.
But it seems that some people, especially older adults, are
just generally more likely to faint than others from a lack
If you are an older adult, you may faint
after meals, especially when you stand up after a meal. This
is because a lot of blood pools in the abdomen as it absorbs
nutrients from the meal and less blood gets to your brain.
As people age, the ability of the nervous
system to control blood pressure becomes less sensitive.
Rising from a lying to a standing position, or standing for
a long time, may cause low blood pressure. This condition,
called orthostatic hypotension, can cause fainting. This
happens because not enough blood is pumped from the heart to
Low blood sugar from diabetic treatment or
other causes can also cause fainting.
Some medicines, such as diuretics (water
pills), blood pressure-lowering medicines, antidepressants,
and antipsychotics may cause fainting.
A type of fainting called vasovagal syncope
can happen when you take a deep breath and push down but
don't allow yourself to breathe out. You may do this, for
example, when you urinate or have a bowel movement. It can
happen when you cough hard or long. Before you faint, you
may feel giddy, lightheaded, or flushed. The fainting is
caused by nerve impulses that slow the heart rate. As a
result, the heart temporarily pumps less blood to the brain.
This is the most common cause of fainting in healthy young
Temporary pressure on a sensitive spot in
the neck causes fainting in some people.
Sometimes heart problems cause fainting.
Irregular heart rhythms are the most
common heart-related cause of fainting. The heart may
beat so rapidly that too little blood gets to the brain.
Or a very slow heart rate caused by heart block or
pacemaker failure may cause fainting.
Some heart attacks immediately damage
the pumping muscle and cause fainting.
Abnormal heart valves can cause drops in
blood pressure that lead to fainting.
Faints also occur because not enough oxygen
is getting to the brain. A rare condition called subclavian
steal may cause unconsciousness when you move your arms
What are the symptoms?
You may faint suddenly without any symptoms.
Or at first you may feel nauseous or sweaty. If your
fainting is caused by a heart problem, you may have a fast
or irregular pulse. Sometimes people say they felt like
their heart was jumping around in their chest. You may feel
short of breath or pressure in your chest. If you have a
heart valve problem, you may have some chest pain,
especially with exertion, before you faint.
How is it diagnosed?
Your health care provider will ask about
your medical history, particularly about the times you have
fainted. How you felt before and after you fainted are
important facts that can help in making the diagnosis. Your
provider will ask about the medicines you take and will
Depending on your age and health history,
your health care provider may want to do some tests.
If your health care provider thinks a
heart problem may be the cause of the fainting, you may
have an electrocardiogram (ECG or EKG). The ECG records
the electrical impulses from your heart. If the first
ECG is normal, your provider may want to monitor your
heart for a longer period of time. A special type of ECG
called a Holter monitor can be worn for 1 to 3 days to
make a recording of your heart rhythm, or another type
of monitor called an event recorder can be used for
several weeks at a time.
You may have an ultrasound test of the
heart called an echocardiogram to see if there are any
problems with the heart muscle or the heart valves.
You may have a stress test which will
give information about the heart rhythm and the blood
flow to the heart.
You may have a chest x-ray.
A tilt table test helps to diagnose
reflex syncope. In this test, your blood pressure is
measured while the table on which you are lying is
progressively tilted toward the head-up position.
Sometimes your health care provider may
order a test of the electrical system of the heart
called an electrophysiology study.
Even with all these tests, the exact cause
for fainting may not be discovered.
How is it treated?
The treatment of fainting is based on the
If vasovagal syncope is the problem, pay
attention to what happens right before you faint. When
you have these symptoms, take precautions to avoid
fainting, or to stop from getting hurt if you do faint.
For example, try to lie down before you faint.
A careful review by your health care
provider of the medicines and dosages you take can
eliminate drugs as a cause for fainting.
Orthostatic hypotension, or a marked
fall in blood pressure when you are standing up, can be
helped by wearing support hose. Getting up slowly from
lying or sitting also helps.
Heart-related problems can often be
repaired. Heart valves causing blockage can be replaced.
Pacemakers can be inserted to correct very slow heart
How do I prevent fainting?
Follow your health care provider's
Drink plenty of liquids, especially in
Eat a healthy diet and eat at regular
times throughout the day.
Let your health care provider know if
your symptoms are getting worse or happening more often,
and if you have had a recent change in medicines.