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No case of exercise-associated hyponatraemia in top male ultra-endurance cyclists: the ‘Swiss Cycling Marathon’

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Abstract

The prevalence of exercise-associated hyponatraemia (EAH) has been investigated in endurance athletes such as runners and Ironman triathletes, but not in ultra-endurance road cyclists. We assessed fluid intake and changes in body mass, urine specific gravity and plasma sodium concentration ([Na+]) in 65 ultra-endurance road cyclists in a 720-km ultra-cycling marathon, the ‘Swiss Cycling Marathon’. The cyclists lost 1.5 (1.7)% body mass (P < 0.01). No athlete developed EAH. Fluid intake was associated with the change in plasma [Na+] (r = −0.32, P < 0.05) and the change in body mass (r = −0.30, P < 0.05). The change in plasma [Na+] was related to post-race plasma [Na+] (r = 0.63, P < 0.0001). To conclude, ad libitum fluid intake in ultra-endurance cyclists in a single-stage ultra-endurance road cycling race showed no case of EAH. Future studies regarding drinking behaviour in different ultra-endurance disciplines might give insights into why the prevalence of EAH is different in the different disciplines.

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Authors and Affiliations

  1. Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland

    Christoph Alexander Rüst, Beat Knechtle, Patrizia Knechtle & Thomas Rosemann

  2. Facharzt FMH für Allgemeinmedizin, Gesundheitszentrum St. Gallen, Vadianstrasse 26, 9001, St. Gallen, Switzerland

    Beat Knechtle

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  1. Christoph Alexander Rüst
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  2. Beat Knechtle
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  3. Patrizia Knechtle
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  4. Thomas Rosemann
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Correspondence to Beat Knechtle.

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Communicated by Susan A. Ward.

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Rüst, C.A., Knechtle, B., Knechtle, P. et al. No case of exercise-associated hyponatraemia in top male ultra-endurance cyclists: the ‘Swiss Cycling Marathon’. Eur J Appl Physiol 112, 689–697 (2012). https://doi.org/10.1007/s00421-011-2024-y

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  • DOI: https://doi.org/10.1007/s00421-011-2024-y

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