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Fainting: Frightening, but seldom serious

Learn why fainting occurs and when you should seek medical attention.

One minute you’re feeling a bit woozy; the next thing you know, you’re flat on your back wondering what happened. No matter what you call it — swooning, passing out, or fainting — the experience is surprisingly common. About a third of people say they’ve fainted at least once.

Defined as a sudden, temporary loss of consciousness, fainting occurs when something interrupts blood flow to the brain. Doctors call it syncope, which comes from a Greek word meaning “contraction” or “cut off.” Although often harmless, fainting can cause injuries and sometimes signals a problem with the heart or circulatory system.

“Witnessing a faint can be scary, because it can look like the person has died,” says Harvard professor Dr. Lewis A. Lipsitz, director of the Division of Gerontology at Beth Israel Deaconess Medical Center and the Institute for Aging Research at Hebrew SeniorLife in Boston. But if it’s really a faint, the person will regain consciousness quickly. If not, call 911 (see “Before and after the fall” for warning signs and what to do if you witness a faint). Here’s the lowdown on the most common reasons people pass out.

Before and after the fall

What does it feel like right before you faint? Sometimes there are no warning signs, but you might feel weak or unsteady for a few seconds beforehand. You might also

  • break out in a cold, clammy sweat

  • feel lightheaded, confused, or nauseated

  • have blurred vision or see spots

  • hear a ringing in your ears

  • yawn and breathe quickly and deeply.

If you feel these symptoms, lie down if possible; if not, sit with your head between your knees to encourage blood flow to your brain.

If you see (or perhaps hear) someone suddenly fall to the ground or slump forward in a chair, how can you tell if you’ve witnessed a faint or something more serious? When a person faints, he or she loses consciousness only briefly — usually less than a minute — and wakes up spontaneously. “You can try to awaken the person with a gentle shake, or by touching their face or calling their name. If it’s a faint, they’ll wake up right away,” says Dr. Lipsitz.

Keep the person lying down for a few minutes and elevate the legs slightly, if possible. If available, a damp, cool cloth on the forehead can be helpful, especially if you’re in a warm room or outside on a hot day. If the person was struck on the head or neck, wait until a medical professional can check for a brain or spinal cord injury. Call 911 immediately if the person is in pain or can’t move an arm or leg.

Vasovagal syncope

Also known as the common faint, vasovagal syncope refers to faints caused by excessive stimulation of the vagus nerve, the part of the nervous system that regulates blood pressure and heart rate. In response to some trigger, the blood vessels in your legs relax and the heart rate slows, making it difficult for blood to return to the heart. Blood pressure drops, and down you go.

Sometimes, the trigger for vasovagal syncope is a strong emotion, such as a response to bad news, the sight of blood, or a feeling of panic or claustrophobia. This type of faint can also occur when you have a bad coughing spell or strain to have a bowel movement, or even if you’ve been standing for a long time.

Vasovagal syncope tends to be more common in people under 35. With age, the nervous system doesn’t react as quickly, so these types of faints occur less frequently. After age 50, other, more dangerous causes become more prevalent, so fainting should be evaluated by a medical professional.

Orthostatic hypotension

Orthostatic hypotension is literally “low blood pressure when standing upright.” It’s also known as postural hypotension. The classic example is a 70-something person who’s been ill (and therefore not eating or drinking normally) and who faints right after getting out of bed in the morning. Older people are more prone to abnormalities in blood pressure regulation because of age, medications, or disease, explains Dr. Lipsitz.

With age, blood vessels tend to stiffen, and the body’s system for monitoring blood pressure system becomes less sensitive. Older people are more likely to take drugs that can worsen orthostatic hypotension, such as beta blockers (which reduce the heart rate) and alpha blockers (which can reduce blood pressure; they’re used in men to treat an enlarged prostate). Older folks are more prone to dehydration, as the sense of thirst diminishes over the years. Also, diseases such as diabetes, cancer, and Parkinson’s (all of which are more common with age) may cause orthostatic hypotension.

As many as 30% of people over age 70 have orthostatic hypotension, but there are several simple ways to lower your risk of fainting from this problem. Drink plenty of fluids, especially when you first wake up. Pump your legs up and down a few times while sitting on the edge of your bed to get your blood flowing. During the day, cross your legs if you feel faint while standing, or sit down as soon as possible.

Abnormal heart rate

If your heart rate is very fast, your blood pressure may fall, and fainting may follow. A number of different heart conditions — from problems with the heart’s electrical system to defective valves — can trigger palpitations, a feeling that your heart is fluttering, racing, or missing a beat. Conversely, a very slow heart rate (known as bradycardia) can also cause you to faint. This condition is usually caused by electrical abnormalities in the heart or heart damage from a heart attack or other disease. Thyroid problems and certain medications can also lead to an abnormally slow or fast heart rate.

Finding the underlying cause

If a young, healthy person faints after an obvious vasovagal trigger, there’s not always a need to see a doctor. But if you faint for the first time after age 40, see a doctor to explore all the potential causes. He or she should check your blood pressure (both sitting and standing, if orthostatic hypotension is suspected) and do an electrocardiogram (ECG), a test that checks for electrical problems with the heart. Your doctor should also review all your medications and change your prescriptions if necessary.

If you have any type of heart disease — including a previous heart attack, a rhythm disorder such as atrial fibrillation, a narrow or leaking heart valve, or heart failure — fainting may foretell a more serious problem and may require more extensive testing, says Dr. Lipsitz.

Image: © Tibanna79/Thinkstock

Posted by: Dr.Health

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