MedicalResearch.com Interview with: Dr. David MacIver Department of Cardiology Musgrove Park Hospital, Taunton Medical Research: What is the background for this study? What are the main findings? Dr. MacIver: The study was prompted by 2 triathletes who presented to our hospital with similar symptoms suggesting they both had had fluid on the lungs whilst swimming. Both athletes were fit and active and had excellent heart function. They were diagnosed with a condition is known as swimming-induced pulmonary oedema or edema (SIPO in the UK and SIPE in the USA). A condition that has been well-documented in Navy seals during training swims in open water. A similar condition has been described in divers sometimes with fatal consequences. Fluid on the lungs or pulmonary oedema more commonly occurs in patients as a complication of severe heart disease such as heart attacks and is called acute heart failure. Pulmonary oedema has also been documented healthy race-horses during competitions. We had recently suggested that acute pulmonary edema in patients with heart disease could be explained by a transient mismatch in the right and left ventricular stroke volumes. We thought it would be interesting to see if a similar mechanism could explain swimming-induced pulmonary edema. We found that factors that might contribute included cold water and high blood pressure. We speculated that cross-training with land based activities (running, cycling) might be relevant. In this study we proposed a possible mechanism for swimming-induced pulmonary edema - fluid from the blood is force into the lung air sacs by the strong right ventricle. In effect, the individual begins drowning in their own lung fluid. (more…)