Changes in plasma creatinine (Pl-Creat), glucose, total proteins (Pl-TP), creatine kinase (Pl-CK), lactate dehydrogenase, aspartate aminotransferase and packed cell volume were evaluated in untrained Beagle dogs before, during and after a 60 min race at an average speed of 9 km/h. There was no major effect of exercise on those parameters except, when phases are compared, a slight increase of Pl-TP during exercise (max. + 6.4%), a moderate but after exercise (delayed increase of Pl-CK max. + 245%) and a slight decrease of Pl-Creat after exercise (max. -9.6%). It was therefore concluded that strenuous exercise in sedentary dogs did not induce major variations in any of routine plasma variables measured and would not lead to clinically relevant misinterpretation. However, for Pl-CK, the interpretation of repeated measures may be misleading if two samples are collected in the same animal before and after exercise.