To assess response to physical stress, gene expression profiles in peripheral blood cells were analyzed using an original microarray carrying 1467 stress-responsive complementary DNA probes.Gene expression was analyzed at 4, 24, and 48 hours after exercising on a cycle ergometer at 60% VO2 max for 1 hour (aerobic exercise) or until exhausted (exhaustive exercise).Institute of Health Biosciences, University of Tokushima Graduate School.Twelve healthy male students of the postgraduate or undergraduate school.The volunteers performed the aerobic or exhaustive exercise on a cycle ergometer.Detection of aerobic exercise-responsive or exhaustive exercise-responsive genes in peripheral blood cells.Aerobic and exhaustive exercise transiently changed the expression of 21 and 16 genes, respectively, with the peak at 4 hours. Only 2 genes significantly responded to both types of exercise. Exhaustive but not aerobic exercise produced a secondary response with significantly altered expression of 14 genes at 24 hours. Five of those genes encode receptors for neurotransmitters (HTR1A, CHRNB2, GABRB3, GABRG3, and LOC51289).The behavior of the individual genes shown here may be informative to objectively assess acute physical stress and exhaustion-associated responses.