What should you know about blackout during workout?

Stopping suddenly after intense effort can briefly reduce blood returning to the heart, especially if you are overheated or dehydrated. Not eating enough can contribute to Hypoglycaemia, and Anaemia may limit oxygen delivery during exertion. An abnormal rhythm such as Atrial Fibrillation can cause palpitations or reduced pumping efficiency. These possibilities overlap, so exercise-related loss of consciousness should not be dismissed as simple overexertion.

Record whether the blackout happened during the hardest part of exercise or just after stopping. Note chest discomfort, unusual breathlessness, pounding or irregular beats, warning dizziness, recent illness, fluid intake, and any supplement or medicine use.

Stop exercising, place the person flat in a safe area, and raise their legs if there is no injury. Check that they are breathing and responsive; do not give food or drink until they are fully awake. Do not return to training or drive yourself for medical care. Arrange prompt assessment before resuming strenuous exercise, even if recovery was quick.

Call emergency services for chest pain, severe breathlessness, an irregular or sustained racing heartbeat, seizure-like movements, serious injury, confusion, or delayed recovery. Treat any blackout during exertion as urgent, particularly when there was no warning or when a close relative has had sudden cardiac death. Keep the person supervised while help is arranged.

Ask whether you need an electrocardiogram, rhythm monitoring, blood pressure checks, or blood tests for glucose and Anaemia. Discuss safe activity limits and whether heat, dehydration, meal timing, medicines, or supplements could have contributed.