Although no univocal evidence has been published within the MS field, aerobic exercise (which usually results in better aerobic capacity) may lead to improvements in the cerebral blood flow,22,23 to the promotion of neuroplasticity9,24 and stimulation of brain-derived neurotrophic factors (BDNFs).25 In addition, better aerobic capacity may positively influence mood and fatigue, as well as reduce stress, anxiety, and depressive symptoms.12,26, –28. This evidence concerns the gene BDNF and Anxiety.