['The Spartathlon ultra distance running race (246 kilometres) is an exhausting physical exercise leading to a state of systemic inflammation associated with dramatic elevation of interleukin-6 and acute-phase reactants to levels seen only in critically ill or patients near death. We sought to study the effect of this severe inflammatory response on the levels of serum procalcitonin.', 'Fifteen healthy endurance-trained runners who participated in the 2006 Spartathlon were studied. Blood samples were taken the day before the race, within 15 min after the end of the race and 48 h after the end of the race. Serum interleukin-6, serum amyloid A protein, C-reactive protein, tumour necrosis factor-alpha and procalcitonin concentrations were determined.', 'Serum interleukin-6, serum amyloid A protein and C-reactive protein were dramatically increased after the end of the race (150-, 116- and 10,470- fold increase of the mean values, respectively). Procalcitonin levels remained within normal range (mean +/- standard error of mean, 0.27 +/- 0.02 microg L(-1), 0.26 +/- 0.02 microg L(-1) and 0.27 +/- 0.02 microg L(-1) before, at the end, and 48 h after the race, respectively). Tumour necrosis factor-alpha measurements revealed no significant changes.'] Does severe aseptic inflammation caused by long distance running ( 246 km ) increase procalcitonin?