In fact, in neurodegenerative disorders such as multiple sclerosis, Alzheimer’s disease, mild cognitive impairment, and Parkinson’s disease, which are related to lower levels of brain-derived neurotrophic factor, the role of physical exercise vs. no exercise has been investigated, and it has been concluded that interventions with physical exercise increase plasma levels of brain-derived neurotrophic factor in patients with neurodegenerative pathology [51]. This evidence concerns the gene BDNF and Parkinson disease.