Rhabdomyolysis/myoglobinemia and NSAID during 48 h ultra-endurance exercise (adventure racing)

Our purpose is to determine whether rhabdomyolysis with myoglobinemia exists during a 48+ h adventure race and if there is a correlation with NSAID use, race time and perceived pain or exertion. Blood samples for analyses of myoglobin (Mb) were collected, and perception of exertion and pain was registered on the Borg-RPE and CR scales, from 20 subjects (3 female, 17 male) Pre-, Mid- and Post-race. Subjects were asked about NSAID use at each sampling and within 12 h pre-race. The result observed was a significant rise in Mb throughout the race, with the NSAID group (n = 6) having significantly lower Mb-Post than the no-NSAID group (n = 14). High Mb-Pre and Post correlated to shorter race time and high Mb-Pre to lower Pain-post. Race time also correlated to NSAID use, with the NSAID group having significantly longer race time than the no-NSAID group. Rhabdomyolysis with myoglobinemia, which might be reduced with NSAID use, exists during a 48+ h adventure race. Indications that high Mb-levels correlate with shorter race time and less pain, and the reasons for the NSAID groups longer race time, warrants further investigation.