Long stress may leave immune cells less able to hear cortisol
Across 41 studies in mice, monkeys and people, long-running stress left immune cells less responsive to cortisol's anti-inflammatory signal, and inflammation rose anyway.
What the study found
Under chronic stress, immune cells stop hearing cortisol
High cortisol and high inflammation at once stops being a contradiction. Across 41 studies in mice, monkeys and people, long-running psychological stress left immune cells less responsive to cortisol's anti-inflammatory signal, and inflammation markers rose even when cortisol was high.
The caveat · Clearer in animals than in people
The mechanism is shown far more directly in the animal studies than in the human ones, where nobody has followed it over time. And this is about how cells respond rather than how much hormone is present, so a blood cortisol reading says nothing about whether it is happening.