Our physical body takes a hit when we experience stress. Even if that stress is not especially negative or traumatic, our body takes the wear.
And if the stress involves danger or trauma, or continues over a significant period of time, our body may just “shut down” in some way.
It has been estimated that 75% or more of the time a patient visits a primary care physician the true reason is stress, psychological difficulty, or something related. In other words, most of the time the problem did not BEGIN with a physical problem or body dysfunction.