Exercise-Associated Hyponatremia and Hydration Status in 161-km Ultramarathoners.

• Autores: Martin D. Hoffman, Kristin J. Stuempfle, Tamara D. Hew-Butler
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 45, Nº. 4, 2013, págs. 784-791
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Dialnet Métricas: 1 Cita
• Resumen

  • AB Purpose: This work combines and reanalyzes 5 yr of exercise-associated hyponatremia (EAH) research at 161-km ultramarathons in northern California with primary purposes to define the relationship between postrace blood sodium concentration ([Na+]) and change in body weight; to examine the interactions among EAH incidence, ambient temperature, and hydration state; and to explore the effect of hydration status on performance. Methods: Prerace and postrace body weight and finish time data were obtained on 887 finishers, and postrace [Na+] was also obtained on a subset of 669 finishers. Results: EAH incidence was 15.1% overall (range, 4.6%-51.0% by year) and had a significant positive relationship with ambient temperature. Of the runners with EAH, 23.8% were classified as overhydrated (weight change, >=0), 40.6% were euhydrated (weight change, <0% to -3%), and 35.6% were dehydrated (weight change, <-3%) at the finish. There was a weak significant relationship (r = 0.17, P < 0.0001) between postrace [Na+] and change in body weight such that a lower [Na+] was more common with increased weight loss. Considering all finishers examined, 18.5% were dehydrated and 34.9% were overhydrated at the finish. There was a weak significant relationship (r = 0.092, P = 0.006) between change in body weight and performance in that faster runners tended to lose more weight. Top finishers varied in body weight change from ~1% gain to ~6% loss. Conclusions: EAH incidence can be high in 161-km ultramarathons in northern California. In this environment, EAH is more common with dehydration than overhydration and is more common in hotter ambient temperature conditions. Because weight loss >3% does not seem to have an adverse effect on performance, excessive sodium supplementation and aggressive fluid ingestion beyond the dictates of thirst are ill advised