Stress will activate the amygdala, which then activates the hypothalamus. The hypothalamus will then release corticotropin releasing hormone (CRH), which travels to the pituitary, and this results in the release of adrenocorticotropic hormone (ACTH). ACTH travels to the outer part of the adrenal glands, the adrenal cortex, and this leads to the release of cortisol, one of the stress hormones.
In the short-term, when encountering a real threat, a quick boost of cortisol can enhance survival, as it increases blood glucose levels so that your muscles can have the energy neccessary to either fight or run from the danger.
However, when you have chronic stress that leads to chronic cortisol exposure, then this can have multiple negative effects on the body, including increased risk of cardiovascular disease and increased risk of type 2 diabetes mellitus (Manenschijn et al., 2013). In addition, chronic cortisol exposure is associated with increased risk of stroke (Christensen et al., 2004).
References:
High long-term cortisol levels, measured in scalp hair, are associated with a history ofcardiovascular disease. Manenschijn L, Schaap L, van Schoor NM, van der Pas S, Peeters GM, Lips P, Koper JW, van Rossum EF. J Clin Endocrinol Metab. 2013 May;98(5):2078-83.
Serum-cortisol reflects severity and mortality in acute stroke. Christensen H, Boysen G, Johannesen HH. J Neurol Sci. 2004 Feb 15;217(2):175-80.
