Faint

Faint, in medical terms, refers to a transient loss of consciousness caused by a temporary reduction in blood flow to the brain. It is commonly called syncope and is usually followed by a rapid recovery. People may experience lightheadedness, dizziness, sweating, or blurred vision before losing consciousness, but some episodes occur without warning.

Most fainting episodes are not dangerous by themselves, but they signal an underlying condition. The most common causes are reflex (vasovagal) syncope, which can be triggered by pain, fear, or prolonged standing; orthostatic hypotension, a drop in blood pressure when standing; and cardiac causes such as arrhythmias or structural heart disease. Other factors include dehydration, overheating, anemia, medications, and, less often, neurological disorders. Risk factors include age, certain medical conditions, and use of some medicines.

Diagnosis typically starts with a detailed history and physical examination, including measurement of blood pressure and heart rhythm. Tests may include an electrocardiogram, blood tests, and sometimes imaging or specialized assessments such as a tilt-table test to evaluate vasovagal responses. Evaluation is guided by age, associated symptoms, and red flags such as fainting during exertion, chest pain, shortness of breath, or injury from a fall.

Treatment aims to address the underlying cause and improve safety. Immediate first aid is to lay the person flat, elevate the legs, loosen restrictive clothing, and ensure an open airway. For vasovagal or orthostatic causes, strategies like hydration, gradual position changes, and, in some cases, salt intake or physical counterpressure maneuvers may help. In persistent or high-risk cases, medical therapy or devices may be indicated. Fainting can also indicate more serious heart problems, warranting professional evaluation.

Beyond the medical sense, faint can describe something barely perceptible in brightness, sound, or significance (a faint light, a faint sound, a faint hope).