BDNF and Anxiety: First, exercise exerts antidepressant and anxiolytic effects via the release of neurotransmitters that cross the blood brain barrier to mediate brain-derived neurotrophic factor expression, stimulating hippocampal neurogenesis and improving mood control.58 Additionally, exercise stimulates production of monoamines,59,60 generating a natural crescendo that stimulates pleasure, satisfaction, and motivation while regulating fatigue.61 Furthermore, exercise improves sleep quality,62 which has a bidirectional association with depression and anxiety.63,64