effect of exercise training on saliva brain derived neurotrophic factor, catalase and vitamin c

background: the balance between production of reactive oxygen species (ros) and antioxidant defense in the body has important health implications. the aim of this study was to investigate the changes in salivary antioxidants: catalase, vitamin c and brain-derived neurotrophic factor (bdnf), in sedentary men at rest and after acute exhaustive exercise.   methods: this randomized controlled clinical trial (the registry code irct2011053212431n1) recruited twenty-five sedentary men (age=21±3yrs; height=172±8cm; weight=66±9kg; vo2 max=37.6±7.4ml•kg-1•min-1) participated in a double-blind randomized experiment. unstimulated whole saliva samples were collected before, immediately and 1 hour after exhaustive treadmill running. catalase, vitamin c (vit c) concentration, and bdnf concentrations were determined using biochemical assays and elisa respectively. repeated measures anova and bonferroni posthoc test were used to analyze data.   results: the results of the present study showed that an acute intensive exercise causes a reduction in salivary catalase, vit c and also bdnf concentration (p<0.05) compared with pre-exercise. both catalase and vit c showed a tendency to return to pre-exercise value after one hour. however, bdnf continued to reduction at least 1 hour after the ending of the training.   conclusion: reduction in antioxidants capacity of saliva might reflects disturbance in natural antioxidant defense mechanisms of the body after an acute intensive physical stress and possible further health threatening consequences.