General adaptation syndrome, a term coined by Hans Selye, describes the myriad influences that chronic stress has on your body.
First among these is what is known as the “alarm reaction”: during this process, the hormones adrenaline and cortisol are released in order to pump you up.
Second, you experience a “stage of resistance”: your mind and body attempt to figure out exactly what is causing the stress reaction so that you can better fight it off.
Third, your body goes through the “phase of exhaustion”, when your body essentially wears out, with resources depleted.
While your body scrambles to find other ways to fight off the attacker, your organs and systems, including your adrenal glands, lymph nodes, and immune system, can suffer a lot of damage. People who experience general adaptation syndrome tend to be sicklier and have high cholesterol and blood pressure: this is often why divorce can be linked to serious illness.
Suffice to say, something that can be so harmful to your body can be equally as disastrous for the brain. Everything from memory formation to attention span suffer when we experience chronic stress and general adaptation syndrome. You can experience lowered levels of norepinephrine, a loss of inability to feel pleasure (known as anhedonia), increased release of cortisol, and an increase of beta waves, all of which are critical hits to your brain’s health.
Khalsa, Stauth (2001-01-01). Brain Longevity: The Breakthrough Medical Program that Improves Your Mind and Memory. Grand Central Publishing.