Fainting, also referred to as “passing out”, is a temporary loss of consciousness. Often, someone who faints will regain consciousness quickly, usually within a minute, and will recover completely.

Fainting is frequently caused by sudden drop in blood pressure that causes a temporary decrease in blood supply to the brain. This can happen to any person at any age, but there are some risk factors that increase the likelihood of it happening.

Risk Factors

Anyone can faint, but people who are at increased risk of fainting include:

• People who are over 65 years of age

• People with heart disease, diabetes, anemia, or high blood pressure

• People who abuse drugs

• People who take medications such as diuretics, sedatives, blood pressure medication, insulin, oral diabetes medications, antiarrhythmic drugs (used to treat abnormal heart rhythms), or blood thinners

• Women who are pregnant

• Exposure to extreme heat

• People with a history of panic attacks

 

Causes

There are many reasons why a person may faint. The most common reason is a sudden drop in blood pressure. This causes the heart rate to slow. It also causes the blood vessels in the lower body to expand, causing the blood to flow downward and pool, making it difficult for blood to travel back up to the brain. When the brain does not receive enough blood, fainting may occur.

Some common triggers of fainting are:

• Strong emotion such as stress, anxiety, or fear
• Extreme pain
• Environment, such as a hot and overcrowded room
• Standing up suddenly from a sitting or a lying down position
• Low blood sugar
• Strong coughing
• Dehydration due to drinking too little fluid, illness, excessive exercise, or sweating
• Medications used for treating conditions like anxiety, high blood pressure, nasal congestion, and allergies
• Medical conditions like diabetes and hypertension
• Emotions like fear, stress, and anxiety

Fainting due to a drop in blood pressure is generally caused by a temporary situation, such as low blood sugar and dehydration; an environmental factor, such as being in a hot, crowded space; or emotion, such as a fear of needles. These types of episodes are the most common reasons for fainting, as well as the least concerning. The patient usually recovers quickly and suffers no long-term effects.

However, occasionally fainting can be a sign of a more serious condition. Anemia, diabetes, hyperventilation due to anxiety disorder, arrhythmia, stroke, cardiac obstruction, and other heart diseases are all serious conditions that may cause fainting, and that need immediate medical attention. A seizure also may cause a victim to become unconscious, but it is due to disordered electrical charges in the brain, not blood flow.

 

Diagnosis

You may want to consult a doctor after a fainting spell, especially if you suspect a serious underlying cause or if it was your first fainting experience. When you visit your physician, he or she will want to know the details surrounding the incident. Your physician may ask questions like:

• Have you had fainting episodes in the past? If so, how often?
• Were you in a situation that made you anxious, nervous, fearful, or stressed?
• Had you taken any medications prior to the incident? If so, what are they?
• Where you hydrated at the time you fainted? Had you eaten a meal recently?
• Were you in an uncomfortable environment at the time you fainted such as a space that was too warm or crowded?
• Do you have diabetes, anemia, a heart condition, or epilepsy?

If the doctor wants to rule out more serious causes for your fainting, he or she will do physical examination and order few tests. The common tests include an electrocardiogram (EKG) that records electrical signals in your heart and detects irregular heart rhythms, a blood sugar test to test for diabetes, and other blood tests to rule out blood conditions like anemia. Based on the results of these tests, you may be evaluated further.

 

Preventing a Fainting Episode

Once you experience a fainting episode, you may come to learn factors that trigger an episode. For instance, someone who is afraid of blood or needles may learn to avoid gory horror movies, or may take extra precautions when getting blood drawn. Someone who has passed out after intense exercise or overheating may avoid strenuous activity on extremely hot days and try to stay hydrated at all times.

You also may start to recognize warning signs that you might faint. Most people notice some or all of these signs before they actually lose consciousness:

• Dizziness
• Changes in vision (spots in the line of vision; tunnel vision – when you can only see what’s in front of you)
• Difficulty hearing or a buzzing in your ears
• Nausea
• Sweating, often a cold sweat
• Rapid heartbeat

If you think that you are having fainting symptoms, you may be able to prevent the episode, or the harm associated with collapsing. First, lie down if possible. If that is not possible, then sit down with your head between your knees. Both of these actions help direct blood supply back to the brain. If you start to feel better, do not get up suddenly. Instead, slowly sit up, remain seated for a bit, then gradually and slowly stand up.

If fainting has occurred from sitting too long and then quickly standing up, remember to take short breaks and walk around. If walking around is not possible, like on a turbulent flight, then occasionally flex and contract your leg muscles, raise your legs, or cross your legs to help improve blood flow back to the heart and brain.

 

Outlook

Fainting is a common condition and can happen to anyone. People of advanced age or people who have had repeated fainting episodes should be aware of the warning signs, and should avoid the conditions that had caused past episodes. After a fainting episode, especially your first, it is important that you see your doctor to know the exact reason for it. In most of the cases, the underlying reason will be situational and will not be serious or have long-term effects. However, fainting due to an illness like anemia, stroke, diabetes, or heart disease may require immediate treatment.

Fainting cannot always be predicted, but it can often be prevented if you pay attention to the warning signs.