Rhabdomyolysis and exercise-associated hyponatremia in ultra-bikers and ultra-runners

Background: exercise-associated hyponatremia (eah),rhabdomyolysis and renal failure appear to be a unique problem in ultra-endurance racers. methods: we investigated the combined occurrence of eah and rhabdomyolysis in seven different ultra-endurance races and disciplines (i.e. multi-stage mountain biking,24-h mountain biking,24-h ultra-running and 100-km ultra-running). results: two (15.4 %) ultra-runners (man and woman) from hyponatremic ultra-athletes (n = 13) and four (4 %) ultra-runners (four men) from the normonatremic group (n = 100) showed rhabdomyolysis following elevated blood creatine kinase (ck) levels > 10,000 u/l without the development of renal failure and the necessity of a medical treatment. post-race creatine kinase,plasma and urine creatinine significantly increased,while plasma [na+] and creatine clearance decreased in hyponatremic and normonatremic athletes,respectively. the percentage increase of ck was higher in the hyponatremic compared to the normonatremic group (p < 0.05). post-race ck levels were higher in ultra-runners compared to mountain bikers (p < 0.01),in faster normonatremic (p < 0.05) and older and more experienced hyponatremic ultra-athletes (p < 0.05). in all finishers,pre-race plasma [k+] was related to post-race ck (p < 0.05). conclusions: hyponatremic ultra-athletes tended to develop exercise-induced rhabdomyolysis more frequently than normonatremic ultra-athletes. ultra-runners tended to develop rhabdomyolysis more frequently than mountain bikers. we found no association between post-race plasma [na+] and ck concentration in both hypo- and normonatremic ultra-athletes. © 2015 2015 chlíbková et al.