While the exact pathophysiology of SIPE remains uncertain, it is believed to be related to exertion, immersion in cold water, and overhydration. The body’s normal response to exercise is to increase cardiac output to meet the increased oxygen demand. Although an increased cardiac output is known to cause pulmonary edema in racehorses, this increase is rarely enough to produce such an effect in humans.1 


Management of Swimming-Induced Pulmonary Edema – American Family Physician.