Exercise-Associated Hyponatremia in Endurance and Ultra-Endurance Performance-Aspects of Sex, Race Location, Ambient Temperature, Sports Discipline, and Length of Performance: A Narrative Review.

Exercise-associated hyponatremia (EAH) is defined as a plasma sodium concentration of <135 mmol/L during or after endurance and ultra-endurance performance and was first described by Timothy Noakes when observed in ultra-marathoners competing in the Comrades Marathon in South Africa in the mid-1980s. It is well-established that a decrease in plasma sodium concentration <135 mmol/L occurs with excessive fluid intake. Clinically, a mild hyponatremia will lead to no or very unspecific symptoms. A pronounced hyponatremia (<120 mmol/L) will lead to central nervous symptoms due to cerebral edema, and respiratory failure can lead to death when plasma sodium concentration reaches values of <110-115 mmol/L. The objective of this narrative review is to present new findings about the aspects of sex, race location, sports discipline, and length of performance. The prevalence of EAH depends on the duration of an endurance performance (i.e., low in marathon running, high to very high in ultra-marathon running), the sports discipline (i.e., rather rare in cycling, more frequent in running and triathlon, and very frequent in swimming), sex (i.e., increased in women with several reported deaths), the ambient temperature (i.e., very high in hot temperatures) and the country where competition takes place (i.e., very common in the USA, very little in Europe, practically never in Africa, Asia, and Oceania). A possible explanation for the increased prevalence of EAH in women could be the so-called Varon-Ayus syndrome with severe hyponatremia, lung and cerebral edema, which was first observed in marathon runners. Regarding the race location, races in Europe seemed to be held under rather moderate conditions whereas races held in the USA were often performed under thermally stressing conditions (i.e., greater heat or greater cold).
Hyponatrémie v souvislosti se cvičením (EAH) je definována jako koncentrace sodíku v plazmě <135 mmol/ L byla poprvé popsána Timothy Noakesem na maratonu Comrades v Jižní Africe v polovině 80. let. Při nadměrném příjmu tekutin dochází k poklesu sodíku v plazmě na hodnotu menší než 135 mmol/L. Mezi rizikové faktory patří dlouhá až velmi dlouhá vytrvalostní zátěž, extrémní klimatické podmínky a ženské pohlaví. Pokud jde o její výskyt ve sportu, EAH má tendenci se vyskytovat při plavání a běhání, ale jen zřídka při jízdě na kole. Zatímco mírná EAH nevede ke klinickým symptomům, těžká hyponatrémie způsobená mozkovým edémem může vést k neurologickým deficitům a dokonce k smrti. Nejlepší prevencí EAH je snížení příjmu tekutin během cvičení.

Keywords

mozkový edém, chladno, cyklistika, teplo, dlouhá tělesná aktivita, běh, plavání, cerebral edema, cold, cycling, heat, prolonged exercise, running, swimming

Citation

Medicina. 2019, vol. 55, issue 9, p. 1-23.
https://www.mdpi.com/1010-660X/55/9/537

Document type

Peer-reviewed

Document version

Published version

Language of document

en

Document licence

Creative Commons Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/