The objective of the present. study was to evaluate a comprehensive set of urinary biomarkers for oxidative damage to lipids, proteins and DNA, in man. Eighteen moderately trained males (mean age 24.6 +/- 0.7) exercised 60 min at 70% of maximal O-2 uptake on a cycle ergometer. Urine fractions for 12 h were collected 1 day before, and for 3 consecutive days after exercise. As biomarkers of lipid peroxidation, 8 aldehydes (i.e. propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal and malondialdehyde-MDA)and acetone were analyzed in urines by gas chromatography with electron capture detection (GC-ECD).