Long-term stress lowers BDNF in the memory center of the brain, which can cause memory problems and reduce the brain's ability to form new connections, but these effects can be reversed with exercise or antidepressant medications.

Source Excerpt

“Chronic stress typically decreases BDNF hippocampal expression, however, when the cause of the stress disappears, the hippocampus shows amelioration of the cognitive and synaptic deficits. To this date, a wide variety of strategies have been assessed to reduce the deleterious effects caused by chronic stress. Infusions of BDNF in the rat hippocampus before a chronic restraint stress protocol can protect against the deficits in learning and memory in the MWM and in LTP and shRNA against BDNF before a stress protocol can revert the spatial reference memory deficits during the post-stress-rest period. Exercise, is a well-known strategy to increase BDNF brain levels, so it has been proposed as a non-invasive way to mimic the effects of direct BDNF administration over chronic stress. found that the hippocampal BDNF increases in response to exercise after a chronic stress protocol. On the other hand, showed that animals that followed a 30 days swimming training program improved their performance in the T maze after being exposed to chronic stress and this enhancement correlated with upregulation of hippocampal BDNF.”