This study examined the effects of exercise on behavior and peripheral blood leukocyte apoptosis in a rat model of chronic fatigue syndrome(CFS).Thirty-six healthy male Sprague-Dawley rats were equally randomized into 3 groups: the control group,CFS model group and the exercise group in terms of body weight.A total of 25 rats entered the final statistical analysis due to 11 deaths during the study.CFS model was established by subjecting the rats in CFS model group and exercise group to electric shock,chronic restraint stress and cold water swim.Besides,rats in the exercise group took running wheel exercise.After a week of conditioning feeding,model construction and running wheel exercise were performed simultaneously,and lasted for 23 consecutive days.The behavior experiments,including running wheel exercise,open-field test,tail suspension test and Morris water maze test,were conducted,either before or after the model establishment.Rats were sacrificed and peripheral blood was obtained for the assessment of lymphocyte apoptosis index by flow cytometry(FCM).It was found that as compared with those in the control group,the weight of the rats was decreased obviously(P<0.01),the mobility time in the open-field and the tail suspension tests was shortened significantly(P<0.01),the time to locate the platform was enhanced(P<0.01)and the cell apoptosis index was increased substantially(P