Vagal syndrome, or vasovagal syncope, is a condition that causes a temporary loss of consciousness due to a sudden decrease in blood pressure, explains Cleveland Clinic. During a vasovagal attack, blood pools in the legs, while blood flow to the brain decreases, causing the person to faint, states Mayo Clinic.
Several factors that can trigger a vasovagal attack depending on the individual's particular sensitivities, notes Mayo Clinic. Trigger examples include the sight of blood, having blood drawn at the doctor's office, exposure to heat, standing up for extended time periods and physical straining, such as during a bowel movement. There may be warning signs before the actual fainting occurs, such as blurry vision, a feeling of light-headedness, tunnel vision or the skin becoming paler than the person's usual color. The individual may suddenly feel very warm or experience a cold, clammy sweat.
A person usually begins recovering from a vasovagal fainting episode within one minute of losing consciousness, according to Mayo Clinic. After regaining consciousness, it is important that the person remain seated or lying down for 15 to 30 minutes because there is an increased risk of passing out again during this time frame. If the person has never experienced a fainting episode before, it is wise to consult with a medical professional to rule out more serious causes.