Endurance athletes at risk of swimming-induced pulmonary oedema

Endurance athletes taking part in triathlons are at risk of the potentially life-threatening condition of swimming-induced pulmonary oedema. Cardiologists from Musgrove Park Hospital, Taunton, writing in the Journal of the Royal Society of Medicine, say the condition, which causes an excess collection of watery fluid in the lungs, is likely to become more common with the increase in participation in endurance sports. Increasing numbers of cases are being reported in community triathletes and army trainees. Episodes are more likely to occur in highly fit individuals undertaking strenuous or competitive swims, particularly in cold water.

Dr David MacIver, lead author, said: "Swimming-induced pulmonary oedema is a well-documented but relatively rare condition that may be misdiagnosed. If an accurate diagnosis and appropriate advice are not given individuals are at increased risk of future life threatening episodes and drowning."

Dr MacIver and colleagues suggest that the unique combination of strenuous swimming, cold water and a highly trained individual can lead to a mismatch in the ventricles' stroke volume as the heart beats, resulting in the accumulation of fluid in the lungs.

"If the athlete is in open water and unable or unwilling to rest while there is ongoing stroke volume difference, pulmonary oedema can take place with potentially fatal consequences", said Dr MacIver. "An increased awareness of the risk of swimming-induced pulmonary oedema among participants, organisers and medical personnel is important, especially as many may have swum before in the same conditions without experiencing symptoms."