doi:10.3390/ijerph182111323engLecina M.López Laval I.Castellar C.Pradas de la Fuente F.Extreme ultra-trail race induces muscular damage, risk for acute kidney injury and hyponatremia: A case reportART-2021-125768A case study involving a healthy trained male athlete who completed a 786 km multistage ultra-trail race. Several markers were analyzed in blood and urine samples: creatinine (SCR) for kidney damage, sodium ([Na+]) for hyponatremia, creatine kinase (CK) for exertional rhabdo-myolysis, as well as other hematological values. Samples were taken before and after the race and during the recovery period (days 2 and 9 after the race). Results showed: SCR = 1.13 mg/dL, [Na+] =139 mmol/L and CK = 1.099 UI/L. Criteria for the determination of acute kidney damage were not met, and [Na+] concentration was above 135 mEq/L, indicating the absence of hyponatremia. Exer-tional rhabdomyolysis was suffered by the athlete (baseline CK increased fivefold), though this situation was reverted after 9 days of recovery. Ultra-trail races cause biochemical changes in athletes, which should be known about by healthcare professionals. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.2021http://zaguan.unizar.es/record/13007510.3390/ijerph182111323http://zaguan.unizar.es/record/130075oai:zaguan.unizar.es:130075International journal of environmental research and public health 18, 21 (2021), 11323 [8 pp]byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess