Understanding Syncope: Symptoms, Causes, Treatment & Prevention

At Tampa General Hospital’s Heart & Vascular Institute, experts treat syncope, the medical term for temporarily losing consciousness (fainting or passing out). Syncope is a relatively common condition that occurs when the amount of blood flowing to the brain suddenly and temporarily decreases.

While syncope often isn’t a cause for concern, in some instances, it can be a sign of a serious medical condition like hypertrophic cardiomyopathy, myocardial ischemia or even heart failure. As such, if you experience syncope, it’s important to promptly consult with an experienced medical provider so that they can determine exactly what caused you to lose consciousness, administer any necessary treatments and recommend steps you can take to avoid fainting again in the future.

What Are the Types of Syncope?

The medical community categorizes syncope into the following types based on what causes the loss of consciousness:

• Cardiac syncope
• Neurological syncope
• Postural orthostatic tachycardia syndrome (POTS) syncope
• Postural syncope (also referred to as “orthostatic syncope,” “orthostatic hypotension” or “postural hypotension”)
• Situational syncope
• Vasovagal syncope (also referred to as “neurocardiogenic syncope”)

In some cases, syncope can’t be classified into one of these types because the loss of consciousness doesn’t have any known cause. It’s important to note that losing consciousness due to emergency conditions like head trauma, intoxication, diabetic hypoglycemia or a heart attack, stroke or seizure does not constitute syncope.

What Are the Causes & Risk Factors of Syncope?

Syncope happens when there’s a sudden, temporary reduction in the amount of blood flowing to the brain. Each of the types of syncope listed above has its own specific cause.

What Causes Cardiac Syncope?

Certain conditions affecting the cardiovascular system (which includes the heart, blood vessels and blood) can lead to cardiac syncope, including:

• Aortic dissection (a tear in the aorta)
• Aortic stenosis (narrowing of the aortic valve)
• Arrhythmias (abnormal heart rhythms)
• Blood clots
• Heart failure
• Hypertrophic cardiomyopathy (thickening of the heart muscle)
• Myocardial ischemia (insufficient blood flow to the heart, often due to an arterial blockage)
• Valve disease

While you should always consult with a physician about syncope, it’s especially important to seek treatment if you think you might have one of these heart conditions.

What Causes Neurological Syncope?

Certain conditions affecting the nervous system (which includes the brain, spinal cord and nerves) can cause neurological syncope, including:

• Migraines
• Normal pressure hydrocephalus
• Seizures
• Strokes
• Transient ischemic attacks (TIAs)

You should also be sure to promptly consult with a doctor if you think you might have one of these neurological conditions.

What Causes Postural Orthostatic Tachycardia Syndrome (POTS) Syncope?

POTS causes someone’s heart rate to significantly increase after standing up from a sitting or lying position. When this happens, it can lead to POTS syncope.

What Causes Postural Syncope?

Postural syncope is caused by suddenly changing positions. For instance, someone may have postural syncope when they stand up too quickly after sitting or lying down. The chances of experiencing postural syncope may increase when someone is dehydrated or has taken certain medications.

What Causes Situational Syncope?

As its name suggests, situational syncope occurs only in certain situations. For example, someone may experience situational syncope when they’re hungry, dehydrated, anxious, scared or in pain. They may also experience situational syncope after wearing a tight collar, turning their neck, lifting weights, coughing or sneezing too hard, hyperventilating, urinating, defecating, drinking alcohol, using drugs or experiencing extreme emotional stress.

What Causes Vasovagal Syncope?

Vasovagal syncope is caused by a sudden drop in blood pressure, which often occurs when someone is emotionally distressed or has been standing for an extended period of time. For example, with regard to emotional distress, someone may faint after seeing blood, having blood drawn or receiving an injection.

What Are the Symptoms & Warning Signs of Syncope?

Losing consciousness is the primary symptom of syncope. With that said, this condition can also cause someone to:

• Feel lightheaded or dizzy
• Feel drowsy or groggy
• Have a headache
• Experience vision changes (e.g., seeing spots or having tunnel vision)
• Black out
• Feel weak or unsteady (especially when standing)
• Fall for no explained reason

In many cases, someone who’s experienced syncope will regain consciousness within just a few minutes. However, they may continue to feel tired or confused for a few hours.

When to See a Doctor for Syncope

You should always consult with a doctor after experiencing syncope. Fainting sometimes results from serious cardiac or neurological conditions that could be dangerous or potentially even life-threatening if left untreated. Even if you don’t have an underlying cardiac or neurological condition, meeting with a physician is still a good idea because it could help you pinpoint exactly what’s causing you to faint and reduce your risk of passing out again in the future.

When to Seek Emergency Treatment for Syncope

Although you should always consult with a physician after experiencing syncope, in some cases you need to seek emergency treatment. For example, you should call 911 if you think you might be experiencing a potentially life- or limb-threatening condition like a heart attack or a stroke. Or, if you’re around someone who has lost consciousness, be sure to contact emergency services if the person remains unconscious for longer than one minute or stops breathing.

Diagnosis & Tests for Syncope

When you visit a medical provider after experiencing syncope, they’ll likely begin by reviewing your personal and family medical histories and asking about what happened before, during and after your loss of consciousness. For example, they’ll want to know:

• When and where you fainted
• What you were doing before you fainted
• How you felt before you fainted
• How long you were unconscious
• Whether you injured yourself when you fainted
• How you felt after you regained consciousness
• How long it took you to recover after fainting
• Whether you’ve fainted multiple times

Your doctor will also conduct a thorough physical examination, which might include measuring your blood pressure and heart rate while you’re standing, sitting and lying down.

Your physician may also order one or more of the following diagnostic tests to determine exactly what caused you to experience syncope:

• Ambulatory monitoring
• Autonomic nervous system test
• Autonomic reflex test
• Blood test
• Computed tomography (CT) scan
• Echocardiogram
• Electrocardiogram (ECG or EKG)
• Electrophysiology study
• Exercise stress test
• Neurological evaluation
• Tilt table test
• Vestibular function test

How Do You Treat Syncope?

The recommended course of treatment for syncope depends on what’s causing the episodes to occur. If your physician diagnoses you with syncope, they’ll prescribe treatments that are tailored to your specific needs. Possible treatment options include:

• Taking medication
• Adjusting your existing medication regimen
• Eating smaller meals on a more frequent basis
• Increasing your sodium or potassium intake
• Drinking more water
• Reducing your caffeine and alcohol intake
• Wearing compression stockings or other support garments
• Elevating your head while sleeping
• Standing up more slowly and carefully
• Avoiding other syncope triggers

If your doctor determines that you have an underlying cardiovascular or neurological condition, they’ll likely focus on treating that issue. For example, if you have a certain type of heart condition, your treatment team may recommend undergoing biofeedback training or having a pacemaker or implantable cardioverter defibrillator (ICD) installed.

What Are the Complications & Long-Term Effects of Syncope?

Syncope itself typically isn’t dangerous, and most people recover quickly after an episode. However, depending on where you are and what you’re doing when you lose consciousness, there’s a chance that you could injure yourself. Also, many of the conditions that can lead to syncope can be dangerous if left untreated—especially the cardiac and neurological ones mentioned above—which is why it’s important to promptly consult with an experienced medical provider.

How Do You Prevent & Reduce Your Risk of Syncope?

Syncope has many potential causes, and while some can be avoided, others cannot. For example, some of the conditions that can lead to syncope are genetic and thus can’t be prevented. With that said, to reduce your risk of experiencing syncope, you may want to try:

• Standing up slowly after sitting or lying down
• Avoiding standing for too long
• Wearing loose clothing and accessories
• Keeping yourself hydrated
• Eating often enough that you don’t feel hungry
• Minimizing your alcohol intake
• Avoiding using recreational drugs
• Managing your stress levels

Depending on what’s causing your syncope, your doctor may recommend additional steps you can take to avoid losing consciousness. For example, certain types of syncope can be prevented by taking medication or having a cardiac device implanted.

Living With Syncope

Many people with syncope start experiencing symptoms before losing consciousness. For example, they may have lightheadedness, dizziness, vision problems, difficulty hearing, heart palpitations, nausea, weakness or sweatiness prior to fainting. If that’s the case for you, taking the following steps whenever you start experiencing these symptoms could prevent you from passing out:

• Sit down or lie down (not only will this reduce your risk of injury if you faint, but also help encourage blood to flow to your brain).
• Tighten your arm muscles and make your hands into fists.
• Raise your legs above the level of your heart.
• Squeeze your legs together or cross them.

Syncope Frequently Asked Questions (FAQs)

It’s always a good idea to consult with a medical provider about syncope. But until you can secure an appointment, here are answers to some of the questions we most commonly receive about syncope.

What Should You Do if Someone Around You Faints?

Having someone faint nearby can be very stressful, and if you’ve never experienced this situation before, you might be unsure of what to do. If someone around you appears to have lost consciousness, you should first check whether they’re breathing. If they’re not, call 911 and administer CPR until the paramedics arrive.

Next, you should help the person lie down and raise their legs about a foot above the level of their heart. If the person who fainted is a pregnant woman, you may want to lay her on her side. Or, if the person can’t lie down, have them sit with their head between their knees for at least 10 minutes. You should also loosen or entirely remove any tight clothing items or accessories (e.g., collars and belts), and if the person fainted from being overheated, try to cool them down by fanning them, applying a cool, damp cloth or having them sip cold water. Also be sure to call 911 if the person doesn’t regain consciousness within one minute, regardless of whether they’re still breathing.

Does Coffee Help Syncope?

Because syncope involves losing consciousness, you might assume that drinking coffee or other caffeinated beverages would help someone with this condition. That’s actually not the case. In fact, in some circumstances, consuming caffeine could actually increase a person’s risk of fainting. For example, if someone has an underlying heart condition, drinking too much coffee could cause their heart to beat too fast or in an irregular rhythm. Instead of coffee, try to drink more water, since staying hydrated can help reduce your risk of syncope.

What Foods Should You Avoid With Syncope?

The recommended diet for someone with syncope will largely depend on what’s causing them to lose consciousness. For example, if your syncope stems from low blood pressure, you may need to eat more salt. Or, if straining during bowel movements causes you to lose consciousness, you might need to increase your fiber intake. If a medical provider has diagnosed you with syncope, be sure to ask them for customized recommendations for what you should (and should not) incorporate into your diet.

That said, regardless of what’s causing your syncope, it’s generally a good idea to stay hydrated and minimize your intake of caffeine and alcohol. If you enjoy eating carbohydrates, opt for unrefined carbohydrates like whole wheat bread and brown rice, since refined carbohydrates like sugar and white flour tend to make syncope symptoms worse. Many people also find it helpful to eat smaller meals more frequently throughout the day, since doing so helps them avoid the hunger that can often trigger a syncope episode.

The TGH Difference for Syncope

Although syncope itself generally isn’t a cause for concern, in some cases it can signal the presence of a serious underlying condition. As such, if you are experiencing the symptoms of syncope, it’s important that you promptly consult with a medical provider who’s experienced in diagnosing and treating this condition.

The knowledgeable team at Tampa General Hospital’s Heart & Vascular Institute treats a wide array of cardiac (heart) and vascular (artery and vein) conditions, including syncope. You can feel confident knowing that you’ll receive highly individualized care from a multidisciplinary team, which includes board-certified cardiac and vascular surgeons, general cardiologists, interventional cardiologists, heart failure specialists, electrophysiologists, radiologists, specialized cardiac and vascular care nurses and technologists. In addition, we’re a trusted academic medical center partnered with the University of South Florida on cutting-edge research and groundbreaking clinical trials.

Tampa General Hospital is an industry leader in treating heart and vascular conditions. Our dedication to delivering world-class patient care has been recognized by Becker’s Hospital Review (which included us on its list of 100 Hospitals and Health Systems with Great Heart Programs), Newsweek (which ranked us as one of America’s Best Specialized Hospitals for Cardiac Care in 2024) and U.S. News & World Report (which named us One of the Nation's Best Hospitals for Heart & Vascular Care and a High Performing Hospital for Heart Attack and Heart Failure Treatment for 2024-25).

Contact Tampa General Hospital’s Heart & Vascular Institute today at (813) 844-3900 or email us at heart-vascular@tgh.org to learn more about why we’re the Tampa Bay community’s top choice for the diagnosis and treatment of syncope and other cardiovascular conditions.