• Fainting (passing out) is when a person loses consciousness for a short amount of time. Usually the person falls to the ground or slumps over
• Awakens in less than 1 minute.

General

• Fainting (syncope) is a brief loss of consciousness due to a temporary decrease in blood flow to the brain.
• There are serious and non-serious causes of syncope.

Findings Suggestive of Serious Cause for Fainting

• Age over 50 years
• Known cardiac disease
• Presence of head or face injury
• Persisting decreased level of alertness after fainting
• Fainting occurs during exercise
• Other symptoms are present: chest pain, difficulty breathing, palpitations, severe headache, internal bleeding

Simple Faints

• Introduction: Simple faints can occur in healthy individuals due to stress, pain, prolonged standing, or suddenly standing up. It is the most common reason for syncope; perhaps 80% of all fainting occurs in this manner. It is also called vasovagal or vasomotor syncope.
• Warning Signs (pre-syncope): There are a number of warning signs that occur immediately before a simple faint. These include pallor, dizziness (lightheadedness), feeling cold or warm, blurred vision, nausea or vague stomach discomfort, sweating, feeling cold. These warning symptoms last for 5 to 10 seconds before passing out occurs. Fainting can sometimes be prevented by sitting down, or even better lying down.
• Symptoms: A brief period of warning symptoms (e.g., dizziness, nausea), followed by unconsciousness, with return to full awareness usually in less than 1 minute; afterwards feeling normal.
• Expected Course: There is often a feeling of tiredness or mild malaise (e.g, being "washed out") for a period of time after a vasovagal fainting episode.
• Predisposing Factors: mild dehydration, fasting, hot weather, sleep-deprived, recent illness, pregnancy, change in altitude.
• Causes: Listed below.

Simple Faints - Causes

• Prolonged standing in one position prior to fainting (called orthostatic syncope): This is a common cause of simple faints. It commonly occurs at church, graduations, weddings, school assemblies, parades, etc. It is more common if one keeps one's knees “locked” – due to pooling of blood in the legs. Anyone who stands long enough in one position will eventually faint.
• Standing up suddenly (especially after lying down) prior to fainting (called orthostatic syncope): Usually this just causes brief dizziness.
• Sudden fearful or disgusting event (emotional pain) prior to fainting (called vasovagal syncope): Examples are any kind of "blood and guts" scenario such as seeing someone vomit, bleed or pass a stool.  Seeing a badly injured person or pet can precipitate syncope.  It can also occur prior to an injection or public performance (e.g., a speech or musical recital).
• Sudden physical pain prior to fainting (called vasovagal syncope). Examples are receiving an injection (e.g., post immunization syncope), having a sliver or sutures removed, or blood draw for lab tests. The stress of the experience probably has more to do with the syncope than the pain itself.