Suggested Novel Risk Factors for Swimming-Induced Pulmonary Edema: Asthma and Limited Open Water Swimming Experience

Linda Kristiansson; Claudia Seiler; Annika Braman Eriksson; Josefin Sundh; Maria Hårdstedt

doi:10.1016/j.chest.2026.02.039

Suggested Novel Risk Factors for Swimming-Induced Pulmonary Edema: Asthma and Limited Open Water Swimming Experience

Chest. 2026 Mar 26:S0012-3692(26)00409-5. doi: 10.1016/j.chest.2026.02.039. Online ahead of print.

Authors

Linda Kristiansson¹, Claudia Seiler², Annika Braman Eriksson³, Josefin Sundh⁴, Maria Hårdstedt⁵

Affiliations

¹ School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Sandviken North Primary Health Care Center, Sandviken, Sweden; Center for Research and Development, Uppsala University/Region Gävleborg, Gävle, Sweden. Electronic address: linda.kristiansson@regiongavleborg.se.
² School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Center for Clinical Research Dalarna-Uppsala University, Falun, Sweden; Department of Anesthesiology and Intensive Care, Falun Hospital, Falun, Sweden.
³ Vansbro Primary Health Care Center, Vansbro, Sweden.
⁴ Department of Respiratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
⁵ School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Center for Clinical Research Dalarna-Uppsala University, Falun, Sweden; Vansbro Primary Health Care Center, Vansbro, Sweden.

PMID: 41903839
DOI: 10.1016/j.chest.2026.02.039

Abstract

Background: Swimming-induced pulmonary edema (SIPE) has gained increasing attention in recent years. However, risk factors for SIPE remain incompletely understood, and existing data are primarily based on small-scale studies.

Research question: Which individual risk factors are associated with SIPE?

Study design and methods: We conducted a case-control study based on Sweden's largest open water swimming event, Vansbrosimningen. Data were obtained through interviews with individuals diagnosed with SIPE in 2017 to 2024 and through a web-based survey administered to control participants without SIPE. Individual factors associated with SIPE were identified by using multiple logistic regression.

Results: A total of 258 cases diagnosed with SIPE and 2,117 control participants were included. A first logistic regression model identified female sex (OR, 5.3; 95% CI, 3.6-7.7), higher age (OR for age ≥ 61 years, 7.3; 95% CI, 3.8-14.2), hypertension (OR, 1.9; 95% CI, 1.2-3.2), heart disease (OR, 6.0; 95% CI, 2.5-14.2), asthma (OR, 1.7; 95% CI, 1.2-2.6), and low frequency of open water swimming during the current season (OR for never, 3.6; 95% CI, 2.4-5.4) as independently associated with SIPE. A second model found that previous respiratory symptoms during open water swimming (OR, 3.5; 95% CI, 2.3-5.2) and acute respiratory tract infection (OR, 10.2; 95% CI, 5.2-20.2) were also strongly associated with SIPE; however, the association with asthma failed statistical significance in this model.

Interpretation: This study confirms previously reported individual risk factors for SIPE and immersion pulmonary edema: female sex, higher age, hypertension, heart disease, respiratory tract infection, and prior SIPE episodes. The data also suggest that asthma and limited experience of open water swimming are associated with an increased risk of SIPE. A comprehensive understanding of the risk factors for SIPE will improve safety during open water swimming and contribute to the development of medical guidelines for SIPE.

Keywords: SIPE; asthma; heart diseases; hypertension; immersion pulmonary edema; respiratory tract infections; risk factor; sex; swimming; swimming-induced pulmonary edema.