Vasovagal syncope causes

Triggers include standing for a long time, heat, emotional distress, pain, fear, seeing blood, and medical procedures. The reflex widens blood vessels and can slow the heartbeat, so the brain receives less blood for a short time. Warning symptoms may include dizziness, nausea, sweating, warmth, tunnel vision, or muffled hearing.

Not every faint is vasovagal. Fluid loss, dehydration, missed meals with hypoglycaemia, anaemia, and abnormal heart rhythms such as atrial fibrillation can produce similar symptoms. The circumstances, position, medical history, and recovery pattern help a clinician separate these possibilities.

Treat the warning as a signal to get safe: lie down and raise your legs, or sit with your head lowered if lying down is impossible. Loosen tight clothing, move away from heat, and ask someone to stay with you. Once you recover, drink fluids if you can do so safely and rise slowly.

Keep a record of what happened, including the trigger, posture, warning symptoms, duration of unconsciousness, injuries, and how quickly you returned to normal. This information is more useful than trying to diagnose the cause from the sensation alone.

Get urgent help for fainting with chest discomfort, breathlessness, a new irregular heartbeat, severe injury, seizure-like activity, confusion, or failure to wake normally. Seek prompt medical review after fainting during exercise, while lying down, without warning, or repeatedly. A first unexplained episode also deserves assessment to exclude heart, blood, or metabolic problems.

Ask which trigger best fits your episode, whether your medicines or health conditions could contribute, and whether you need blood pressure checks, blood tests, or an electrocardiogram. Bring an account from anyone who witnessed the event.