Fig.2.

Regular physical activity produces a progressive and sustained increase in the expression of brain-derived neurotrophic factor (BDNF). Elevation of intraparenchymal BDNF protein levels are graded with the duration (or total period) of regular sessions of physical activity, with profound mRNA increases detectable starting from 2–3 days. Cessation of exercise is followed by a gradual decline of BDNF protein level though it has been shown to remain significantly higher than baseline levels for up to 2 weeks. Notably, a return to exercise results in a rapid reinstatement of elevated protein levels, more quickly than is typical of exercise-naïve rodents [201, 202].