Interstitial lung edema triggered by marathon running.

The purpose of this study was to determine whether marathon running causes lung edema, and if so, to determine its effects on runners. Posterior/anterior (PA) radiographs were taken one day before the marathon and at 19, 55, and 98min post-marathon in 26 runners. The pre and post exercise radiographs of each runner were collated, and then read simultaneously. Two physicians interpreted the images independently in a blinded fashion. The PA radiographs were viewed together at each time-point and findings suggestive for interstitial lung edema were rated as 'mild,' 'moderate,' or 'severe' based on four different radiological criteria. Forty-six percent of the runners presented radiographic findings suggestive of mild to severe interstitial lung edema. Radiographic findings persisted until 98-min post-marathon, with at least moderate degree increases found more frequently in women (55%) than men (6%) (p<0.01). In conclusion, about half of the runners developed interstitial lung edema of varying degrees post-exercise with the incidence being higher in women compared to men.