Temporary loss of consciousness. Fainting occurs when there is an insufficient supply of blood and oxygen to the brain for a short period, which can happen if blood vessels in the body dilate (widen), causing blood (which carries, vital oxygen) to drain away from the brain. Fainting may be characterized by a sudden pallor, or pale skin; nausea; sweating; loss of consciousness; and twitching or brief seizures.
Fainting, or syncope, is a temporary loss of consciousness caused by inadequate supply of blood to the brain. It may be preceded by nausea, sweating, loss of vision, and ringing in the ears. It is most often caused by a reduction in the amount of blood returning to the heart from the veins. This lowers the output of the heart. It may be provoked by hot weather or prolonged standing or be an effect of fear or revulsion. Occasionally fainting on standing occurs in people with low blood pressure (usually as a result of overaction of drugs they take to control high blood pressure, or autonomic neuropathy (in which normal vasomotor reflexes are absent). A prolonged rise in pressure within the chest, caused by coughing, micturition, or valsalva’s manoeuvre also impedes venous return and may cause fainting. Hypovolaemia produced by bleeding, prolonged diarrhoea, or vomiting may also cause fainting. Cardiac causes, such as severe aortic valve disease or rhythm disturbances (particularly complete heart block or very rapid tachycardias), may result in fainting. Treatment must be directed towards the underlying cause, but immediate first aid consists of laying the patient down and elevating their legs.
Syncope, the medical term for it, is a temporary blackout caused by a decrease in blood supply to the brain.
Fainting episodes often occur due to a vasovagal attack, which is when overactivity of the vagus nerve — a nerve that regulates crucial organs like the lungs and heart — slows down the heartbeat and lowers blood pressure. This decreases the blood flow to the brain. These attacks typically come after symptoms like sweating, nausea, dizziness, and weakness, and are often triggered by pain, stress, shock, an over-crowded environment, or persistent coughing. Fainting can also be due to postural hypotension, or low blood pressure, which can happen when someone stands still for a prolonged period or gets up abruptly. This issue is frequently found in older people, those with diabetes, and those taking medications for high blood pressure or drugs that widen blood vessels.
In the majority of instances, a person recovers from fainting once regular blood flow to the brain resumes. This typically occurs within a few minutes since fainting causes the individual to fall into a lying position, thereby reinstating blood flow to the brain. However, if unconsciousness is prolonged or if there are recurrent fainting episodes, medical intervention is necessary.
The condition occurs because of a rapid drop in blood pressure, leading to insufficient blood supply to the brain. This can happen after a scare, in an overly warm room, or when rising from bed after a weakening illness. The patient turns extremely pale, expresses discomfort, and then collapses.