Vasovagal syncope and exercise

During exercise, the heart and blood vessels adjust to meet the body’s needs. A faint may occur around exertion if blood pressure falls, especially with heat, inadequate fluids, illness, or an abrupt stop after effort. Some people notice dizziness, nausea, sweating, weakness, or narrowing vision first. Fainting in the middle of exercise is more concerning than fainting after stopping and needs medical review. Anaemia, dehydration, low blood sugar, and an abnormal rhythm can resemble or contribute to a vasovagal episode.

Stop as soon as symptoms begin; sit or lie down away from traffic, equipment, and edges. Tell a training partner what happened. Warm up and cool down gently, avoid very hot conditions, drink according to your clinician’s advice, and do not exercise while unwell or fasting. Resume with easy activity when your clinician agrees, using supervision and rest breaks. Keep a record of the activity, position, food and fluid intake, symptoms, and recovery time.

Get urgent help for fainting during exercise, chest discomfort, breathlessness, a pounding or irregular heartbeat, severe injury, seizure-like activity, or prolonged confusion. Arrange prompt review after a first faint, repeated episodes, or symptoms without a warning phase. Do not return to strenuous training until a clinician has considered heart rhythm and other medical causes.

Ask which activities are suitable now, whether you need an electrocardiogram or blood tests, how to manage fluids and meals around exercise, whether someone should supervise you, and what symptoms mean you must stop immediately.