@article{2987515,
    title = "Exercise-associated hyponatremia during the olympus marathon ultra-endurance trail run",
    author = "Arnaoutis, G. and Anastasiou, C.A. and Suh, H. and Maraki, M. and Tsekouras, Y. and Dimitroulis, E. and Echegaray, M. and Papamichalopoulou, D. and Methenitis, S. and Sidossis, L.S. and Kavouras, S.A.",
    journal = "Nutrient Cycling in Agroecosystems",
    year = "2020",
    volume = "12",
    number = "4",
    publisher = "MDPI AG",
    issn = "1385-1314",
    doi = "10.3390/nu12040997",
    keywords = "creatine kinase;  glucose;  hemoglobin;  potassium;  sodium;  sodium, adult;  anthropometry;  Article;  athlete;  biochemical analysis;  body mass;  body weight;  centrifugation;  controlled study;  dietary intake;  endurance;  exercise;  female;  glucose blood level;  hematocrit;  human;  humidity;  hyponatremia;  hypovolemia;  major clinical study;  male;  marathon runner;  middle aged;  plasma volume;  prevalence;  relative density;  sodium blood level;  sodium intake;  temperature;  urinalysis;  urine osmolality;  urine sampling;  blood;  drinking;  hyponatremia;  nutritional status, Adult;  Athletes;  Drinking;  Exercise;  Female;  Humans;  Hyponatremia;  Male;  Marathon Running;  Nutritional Status;  Physical Endurance;  Sodium",
    abstract = "Research on hyponatremia during mountain marathons is scarce. The present study aimed to investigate the prevalence of exercise-associated hyponatremia during a 44-km trail running race that reached an altitude of 2780 m (Olympus Marathon). Sixty-two runners (five women) who completed the race participated in the study (age: 34.4 ± 8.6 years; height: 1.77 ± 0.06 m; and weight: 75.3 ± 10.0 kg). Anthropometric characteristics, blood, and urine samples were collected pre-and post-race. Food and fluid intake were recorded at each checkpoint. Due to race regulations, the runners could not carry any additional food and fluids besides the ones provided at specific checkpoints. Five runners (8%) exhibited asymptomatic hyponatremia (serum sodium <135 mmol·L−1). Serum sodium in the hyponatremic runners decreased from 138.4 ± 0.9 (pre) to 131.4 ± 5.0 mmol·L−1 (post), p < 0.05. Plasma osmolality increased only in the eunatremic runners (pre: 290 ± 3; post: 295 ± 6 mmol·kg−1; p < 0.05). Plasma volume decreased more in the hyponatremic compared to eunatremic runners (−4.4 ± 2.0 vs. −3.2 ± 1.4%, p < 0.05). Lastly, dietary sodium intake was lower in the hyponatremic runners compared to eunatremic (789 ± 813 vs. 906 ± 672 mg; p < 0.05). The incidence of hyponatremia among the athletes was relatively low, possibly due to race conditions. © 2020 by the authors. Licensee MDPI, Basel, Switzerland."
}