The stressed brain

Two small structures, two opposite reactions to stress that never switches off. Move the slider, then add exercise.

calm
Side view of the brain: under chronic stress the amygdala becomes more reactive and the hippocampus smaller; exercise supports the hippocampus front Amygdala threat detector Hippocampus memory, learning, context Alarm reactivity Hippocampal volume Relative, not to scale.

Schematic; changes are exaggerated for visibility – real differences are a few percent. Sources: Vyas et al., J Neurosci 2002 (animal data); Schmaal et al., Mol Psychiatry 2016; McEwen, Physiol Rev 2007; Erickson et al., PNAS 2011.