Haem-oxygenase-1 (HO-1) is an antioxidant stress protein that is mainly induced by reactive oxygen species, inflammatory cytokines and hyperthermia. We assessed the influence of different types of exercise on HO-1 expression in leukocytes of the peripheral blood in three groups of male participants: a short exhaustive run above the lactate steady state (n = 15), eccentric exercise (n = 12) and an intensive endurance run (half-marathon, n = 12). Blood samples were taken at rest and up to 24 h after exercise. Blood lactate concentration after exercise was 9.0 ± 2.1, 3.8 ± 1.6 and 5.1 ± 2.2 mmol · l − 1 (mean ± s) for the exhaustive run, eccentric exercise and half-marathon groups, respectively (P < 0.05). Creatine kinase concentration was highest 24 h after exercise: 133 ± 91, 231 ± 139 and 289 ± 221 U · l − 1 for the exhaustive run, eccentric exercise and half-marathon groups, respectively (P < 0.05). The maximal increase in leukocyte counts after exercise was 11.5 ± 19.2, 6.2 ± 1.4 and 14.7 ± 2.1 × 109 · l − 1. There was no change in HO-1 as a result of the short exhaustive run or the eccentric exercise, whereas the half-marathon had a significant stimulatory effect on HO-1-expression in lymphocytes, monocytes and granulocytes (P<0.001) using flow cytometry analyses. In conclusion, eccentric exercise alone or short-term heavy exercise are not sufficient to stimulate the antioxidative stress protein HO-1 in peripheral leukocytes