Exercise-Associated Postural Hypotension

Exercise-associated postural hypotension, also called exercise-associated collapse (EAC), is an inability to stand or walk unaided because of light-headedness, faintness or collapse after finishing or stopping exertion.

It is the most common cause of collapse in endurance events and is typically benign, so the skill lies in separating it from the dangerous causes of collapse. Timing is a strong clue, not a diagnosis: collapse after stopping makes it more likely, while collapse during exercise is treated as a serious cause until proven otherwise. It responds quickly to lying flat with the legs raised, and fluid is rarely needed.