When your brain doesn’t get enough oxygen, you may experience lightheadedness and weakness, as if you’re going to faint. If you don’t, that’s a presyncope. If you do faint, that’s called syncope.
Basically, presyncope (pre-sin-co-pee) is the sensation that you’re going to faint. You might feel lightheaded and weak, among other symptoms, but you don’t actually pass out. You typically feel better within a few minutes.
If you do faint and regain consciousness, that’s called syncope.
Keep reading as we explore the symptoms of presyncope, what causes it, and when you should see a doctor.
You’re more likely to have symptoms of presyncope when you’re sitting or standing, rather than when you’re lying flat. It might also occur when you get up quickly after sitting or lying down.
Symptoms of presyncope can include:
- lightheadedness, general weakness
- tunnel vision, blurry vision
- slurred speech
- trouble hearing
- nausea or vomiting
- heart palpitations
These symptoms can last from just a few seconds to several minutes before they pass.
Presyncope happens when your brain isn’t getting the oxygen it needs due to decreased blood flow.
This can happen for a variety of reasons, some benign and some that can be serious. There may be several contributing factors.
Some causes for presyncope include:
- a temporary drop in blood pressure
- prolonged standing
- intense nausea or pain
- hypoglycemia, or low blood sugar, which may or may not be due to diabetes
- neurally mediated hypotension, which causes your blood pressure to drop when you stand up from a sitting or lying position
Vagal presyncope is a term used to describe when the sight of blood, emotional reaction, urination, or eating a large meal (among other causes) causes the heart to speed up and the body to release chemicals that drop the blood pressure.
Presyncope is a side effect of some medications, particularly those that can lower your blood pressure.
Cardiac arrhythmia, a condition in which your heart beats too slow, too fast, or erratically, is an uncommon cause of presyncope and syncope.
An observational study involving emergency room visits found that 5 percent of people seen for presyncope had serious outcomes. The study involved only two urban hospitals in the same city, so it’s difficult to say what that means in the general population and in non-urban locations.
If you’ve had an episode of presyncope, see your doctor. It’s not always possible to determine the cause, but it’s important to rule out or diagnose serious health problems that require treatment.
It’s likely your doctor will approach the diagnosis of presyncope the same way they would if you had fainted.
Be sure to report all symptoms, even if they seem unrelated, especially symptoms that occurred immediately before or after dizziness.
This will help differentiate a bout of dizziness from vertigo, a sensation of imbalance or motion when there is no motion, and presyncope. This is important because dizziness and vertigo can be due to other causes, such as migraine or stroke.
Your doctor will take your vital signs and may want to check your blood pressure while you’re sitting, lying, and standing. Your physical exam will help guide further diagnostic testing, which may include:
If there are no identifiable medical conditions causing your presyncope, you may not be given any treatment at all.
Whether or not you’ve experienced presyncope before, you can’t know for certain if you’re actually going to faint or not.
Even if you don’t faint, feeling dizzy and lightheaded can be disorienting and could cause you to lose your balance. So, it’s important to sit, lie down with your legs up, or get low to the ground until it subsides to lower your risk of falling and getting injured. You can also squeeze your fists together to try to raise your blood pressure.
If you’ve had more than one episode of presyncope, try to avoid possible triggers such as:
- standing up too quickly
- spending long periods of time on your feet
- hot, stuffy rooms
- spending too much time out in the hot sun
- exercising in the heat
- drinking too much alcohol
- skipping meals
If you tend to feel anxious and lightheaded before medical procedures like blood tests or vaccinations, talk to your doctor or nurse about lying down for this type of procedure.
Any treatment you do get will depend on the cause, if it can be determined. Any known medical conditions, such as diabetes or heart disease should be treated and monitored.
When presyncope is due to a medication, continue to take your medication until you talk to your doctor about alternatives.
As noted above, some conditions, such as neurally mediated hypotension or hypoglycemia, may cause presyncope.
However, detailed research on risk factors for presyncope is limited. A reason it’s difficult to pin down is that it passes quickly and may only happen once. People who feel faint, but don’t actually lose consciousness, may not seek medical attention or even inform their doctor.
Of those who do see a doctor, symptoms have usually resolved and a diagnosis of presyncope may never be made.
Presyncope is the sensation of feeling faint without actually fainting. It can last only a few seconds to a few minutes. Although it may very well be a benign event, it is sometimes indicative of a more serious health issue and should be checked out.
It’s important to talk to your doctor about all your symptoms so you can get a diagnosis and any treatment you may need. If there are no serious medical issues, you can try to identify and avoid whatever triggers you to feel faint.
Be sure to keep your doctor up to date on any new or changing symptoms.