Why/How would it do this?
I don’t see how stress could lead to a physical illness.
The idea that “mental” and “physical” are somehow separate is an ancient old lie that needs to be put to rest. Everything “mental” happens in your nervous system–a “physical” part of your body. The stomach is connected to said nervous system…
I don’t know how or why, but I can assure you it happens to me. Whenever I’m under extreme stress, I get very nauseous, sometime to the point of vomiting. Or I’ll get a terrible stomachache, followed later by diarrhea. I’ve always joked that stress goes straight to my digestive system.
Some people get headaches, I throw up.
You’re not alone.
Stress causes your body to release adrenaline, which is good for keeping you alive (i.e., running and fighting) but also has side-effects like nausea. But I can’t seem to find whether the nausea is caused directly by the adrenaline or by virtue of the fact that adrenaline shunts blood into the muscles and away from other parts of the body (i.e., your digestive tract … causing nausea?).