Dr. MJ Bazos MD,
Fainting: What Causes
What causes fainting?
Fainting, which is also called syncope, can be
related to many different things. More than one thing may be the cause of
fainting. Sometimes a specific cause for fainting can't be found.
Fainting can happen when not enough oxygen flows
through your blood and into your brain. You lose consciousness, or "pass out,"
for a very brief time -- just a few seconds or minutes.
A sudden drop in your blood pressure can cause
you to faint. Sometimes your heart rate and blood vessels can't react fast
enough when your body's need for oxygen changes. This is very common among older
people. It can happen when:
- You stand up fast.
- You work or play hard, especially if it's very
- You begin to breathe too fast (called
- You get very upset. Being upset can affect the
nerves that control your blood pressure.
- You're taking medicine for high blood pressure.
Coughing, urinating and
stretching can also get in the way of the flow of oxygen to the brain and may be
a cause of fainting. If you faint once during one of these activities, it's
probably not something to worry about. But if it happens more than once, you
should tell your doctor about it.
If you faint when you turn your head to the
side, the bones in your neck may be pinching on one of the blood vessels that
leads to your brain. If this happens to you, be sure to tell your doctor about
A drop in your blood sugar may also cause you to
faint. This can happen if you have diabetes, but it may also happen if you don't
eat for a long time.
Some prescription medicines can cause fainting.
Be sure to talk to your doctor if you think your fainting may be related to a
medicine you're taking. Alcohol, cocaine and marijuana can also cause fainting.
More serious causes of fainting include seizures
and problems with the heart or with the blood vessels leading to the brain.
How will the cause of my fainting be
Your doctor will probably want to talk to you
about exactly what was happening when you fainted. He or she may ask you for
details about how you felt right before and right after you fainted. Your doctor
will probably also want to examine you.
What should I do if I think I'm
going to faint?
If you feel like you're going to faint, lie
down. If you can't lie down, sit and bend forward with your head between your
knees, to help get the blood flowing to your brain. Wait until you feel better
before trying to stand up.
Should I see my doctor if I faint?
You probably don't need to go to your doctor if
you have only fainted one time and you are in otherwise good health. Fainting is
common and usually not serious. However, if you have serious health problems,
especially heart-related problems, high blood pressure or diabetes, you probably
should see your doctor. See your doctor if your fainting is associated with any
of these features:
- Irregular heart beat
- Chest pain
- Shortness of breath
- Sudden onset (no warning signs)
- Blurred vision
- Trouble talking
- Fainting when you turn your head
- Fainting more than once in a month