Exercise-Associated Hyponatremia in Endurance Sports: Risk Factors, Pathophysiology and Prevention – A Narrative Review
DOI:
https://doi.org/10.12775/QS.2026.73.75538Keywords
exercise-associated hyponatremia, endurance sports, endurance exercise, hydration, fluid balance, sodium balance, arginine vasopressin, risk factors, preventionAbstract
Background. Exercise-associated hyponatremia (EAH) is a potentially serious disturbance of water and sodium homeostasis occurring during or after prolonged endurance exercise. Although excessive fluid intake is an established risk factor, EAH results from interactions between fluid intake, arginine vasopressin activity, sodium balance, exercise duration, environmental conditions, and individual characteristics.
Aim. This narrative review aimed to summarize current evidence on the epidemiology, pathophysiology, risk factors, and prevention of EAH in endurance sports, with emphasis on recent findings and modifiable factors.
Methods. Relevant literature was identified primarily through PubMed searches and reference-list screening. Particular emphasis was placed on studies published between 2020 and 2026, while selected earlier studies were retained as foundational evidence. Original studies, systematic and narrative reviews, clinical guidelines, and relevant physiological research were considered.
Results. EAH occurs in marathon running, triathlon, ultramarathon, and mountain endurance events, with substantial variation in reported prevalence. Excessive fluid intake relative to free-water excretion remains the most consistently identified modifiable risk factor. However, EAH may also occur despite body mass loss, indicating that sodium losses and other physiological mechanisms contribute in some athletes. Exercise-associated arginine vasopressin activity facilitates water retention during prolonged exercise. Current evidence does not support universal sodium supplementation as a reliable preventive strategy. Hydration beliefs and planned drinking behaviors may also influence risk.
Conclusions. EAH is a multifactorial disorder rather than simply a consequence of sodium depletion or excessive water consumption. Prevention should emphasize avoiding forced drinking, individualized hydration strategies, and athlete education regarding fluid and sodium balance.
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Copyright (c) 2026 Jakub Gałwiaczek, Jarosław Dudek, Damian Grębosz, Krzysztof Lis, Aleksandra Łysak, Aleksandra Kalisz, Łucja Ilkiewicz
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