The neurotrophin brain-derived neurotrophic factor (BDNF) has been implicated in depression and anxiety. Antidepressants and exercise increase BDNF expression, and both have an antidepressant and anxiolytic activity. To further characterize the association of anxiety, BDNF and exercise, we studied panic disorder patients (n=12) and individually matched healthy control subjects (n=12) in a standardized exercise paradigm. Serum samples for BDNF analyses were taken before and after 30min of exercise (70 VO(2max)) or quiet rest. The two conditions were separated by 1 week and the order was randomized. Non-parametric statistical analyses were performed. There was a negative correlation of BDNF concentrations and subjective arousal at baseline (r=-0.42, p=0.006). Compared to healthy control subjects, patients with panic disorder had significantly reduced BDNF concentrations at baseline and 30min of exercise significantly increased BDNF concentrations only in these patients. Our results suggest that acute exercise ameliorates reduced BDNF concentrations in panic disorder patients and raise the question whether this is also found after long-term exercise training and if it is related to the therapeutic outcome.