Running out of brain.

Stroke is the third most common cause of death after coronary artery disease and cancer in the UK, and running is a popular form of exercise, and increasingly, people are participating in large scale endurance events such as marathons and half-marathons. We describe here two cases of young men suffering a stroke after running a marathon and who were subsequently found to have a patent foramen ovale (PFO). We have reviewed the existing literature concerning stroke in those undertaking long-distance running, and suggest why PFO may have been important etiologically in our two patients. We tentatively suggest that individuals with a PFO who engage in long distance running may be at increased risk of stroke, independent of other cerebrovascular risk factors.