Fainting: Why People Pass Out, What to Do and When to Be Seen

What it involves

MedlinePlus describes fainting as a brief loss of consciousness caused by a drop in blood flow to the brain. The episode most often lasts less than a couple of minutes, recovery is usually quick, and the medical name is syncope.

Who this is for

• Patients who fainted once and want to know why it happened
• Patients who have fainted more than once, or feel faint when standing up
• Patients who take medicines for blood pressure, anxiety, or depression and have felt lightheaded
• Family members who saw someone pass out and want to know what to watch for

What to expect

• Questions about what happened before, during, and after, including anything a witness saw
• An exam focused on the heart, lungs, and nervous system, with blood pressure checked lying down and standing
• A review of your medicines, hydration, and blood sugar
• Further tests or a referral if a provider suspects a heart rhythm problem or another cause

What happens before a faint

MedlinePlus says that before fainting you may feel weak, sweaty, or nauseated, you may have the sense that your vision is narrowing into tunnel vision, or noises may fade into the background. When you do faint, you lose consciousness, muscle tone, and the color in your face. Sitting or lying down at the first warning sign can prevent a fall. The dizziness guide covers the lightheaded feeling that comes without passing out.

Common triggers

MedlinePlus lists fainting that happens during or after coughing very hard, a bowel movement with straining, standing in one place too long, or urinating, especially at night. It can also follow emotional distress, fear, or severe pain. Rapid deep breathing, standing up suddenly from lying down, dehydration, and bleeding can each drop blood pressure. The low blood sugar guide explains another cause on its list.

Causes that need a closer look

Some causes are more serious. MedlinePlus lists certain medicines, including some used for anxiety, depression, and high blood pressure, drug or alcohol use, seizures, and heart disease such as an abnormal heart rhythm, heart attack, or stroke. Because a heart problem is the cause a provider least wants to miss, an irregular or pounding heartbeat is taken seriously. The heart palpitations guide and EKG screening page cover related ground.

What to do for someone who has fainted

MedlinePlus advises checking the person's airway and breathing, calling 911 and starting CPR if needed, loosening tight clothing around the neck, and raising the feet about 12 inches above the heart. If the person has vomited, turn them on their side. Keep them lying down for at least 10 to 15 minutes in a cool, quiet space. For yourself, MedlinePlus suggests getting up slowly from lying or sitting and telling a provider before blood draws if needles make you faint.

When to call 911

MedlinePlus says to call 911 if the person fell from a height, does not become alert quickly, is pregnant or over age 50, has diabetes, or has chest pain, pressure, or a pounding or irregular heartbeat. Loss of speech, vision problems, inability to move a limb, convulsions, a tongue injury, or loss of bladder or bowel control are also on its list. The chest pain guide explains how to decide between an ambulance and an appointment.

What an office visit can do

Even when it is not an emergency, MedlinePlus says to be seen if you have never fainted before, faint often, or have new symptoms with the faint. It lists questions about the episode, an exam of the heart, lungs, and nervous system, and blood pressure in different positions. Tests that may be ordered include blood tests for anemia, an electrocardiogram, heart rhythm monitoring, and an echocardiogram. Treatment depends on the cause.

Sources

• MedlinePlus — Fainting
• MedlinePlus — Fainting (health topic)