I was actually just reading about this in Caste: The Origins of our Discontent. The author talks about how one’s body goes into stress or anxiety or defense mode when the person knows they’re being followed, watched, or otherwise scrutinized. She brought race into it. A Nigerian man, who was just a person in his country, was healthy as anything. He got to the U.S. and within a year, his doctor told him he was suddenly pre-diabetic and had high blood pressure. He never had those things in his country. He learned that being Black in the U.S. is a very different experience than being Black in a Black-centric country. The author elaborated more about those in poverty, women, and being a minority in general. Having that “fight or flight” triggered in the body, sometimes for hours or days or weeks at a time, degrades the body’s natural defenses, making them more vulnerable to disease.