title: Rhabdomyolysis and exercise-associated hyponatremia in ultra-bikers and ultra-runners.
abstract: 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.
authors.affiliation: Centre of Sports Activities, Brno University of Technology, Brno, Czech Republic.
authors.forename: Daniela
authors.initials: D
authors.lastname: Chlíbková
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.affiliation: Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Ivana
authors.initials: I
authors.lastname: Tomášková
authors.affiliation: Faculty of Sports Studies, Masaryk University, Brno, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Novotný
authors.affiliation: Institute of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.
authors.forename: Alena
authors.initials: A
authors.lastname: Žákovská
authors.affiliation: Center for Adult Medicine in Bohunice, University Hospital Brno, Brno, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Uher
mesh_terms: D000328:Adult; D056352:Athletes; D001642:Bicycling; D015992:Body Mass Index; D015897:Comorbidity; D003402:Creatine Kinase / Q000097:blood; D003404:Creatinine / Q000652:urine; D015444:Exercise; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000097:blood* / Q000652:urine; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D012206:Rhabdomyolysis / Q000097:blood* / Q000652:urine; D012420:Running; D012964:Sodium / Q000097:blood
chemical_list: D012964:Sodium; D003404:Creatinine; D003402:Creatine Kinase; D011188:Potassium
keywords: Long distances; Mountain biking; Running