LONDON (Bloomberg) — Marathon running may trigger a lung condition that causes shortness of breath, severe coughing, and in serious cases, heart attacks or respiratory failure, according to a new study.

Half of 26 runners in the study who completed the 2011 Steamtown Marathon in Pennsylvania had some form of pulmonary edema, in which fluid builds up in the air sacs of the lungs, about 20 minutes after the race, according to research led by Gerald Zavorsky of Marywood University. Twenty percent of the participants had a moderate or severe form of the condition, the study showed. The research was presented Monday at the European Respiratory Society annual meeting in Vienna.

The research adds to previous studies that showed marathon runners are at risk of high blood pressure and heart complications. There was no relation between marathon race time and the development of pulmonary edema, suggesting the condition can occur across all abilities, the researchers said.

“While pulmonary edema can be a negative consequence of marathon running, regular exercise can also keep you fit and healthy,” Zavorsky said.

in a statement.

Researchers took chest X-rays of the runners the day before the race and then at 19, 56 and 98 minutes after the race. Women were at much higher risk compared with men in developing pulmonary edema.

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