The stress response runs through four stations: hypothalamus releases CRH → pituitary releases ACTH → adrenal cortex releases cortisol → cortisol feeds back to suppress hypothalamus and pituitary (negative feedback).In acute stress, this loop turns on and off cleanly — the brake is what makes that possible.
2 · After chronic stress: blunted, not high
After chronic burnout the axis is often blunted: the same stressor releases less cortisol than it should, and the daily curve flattens.Many assume chronic stress means cortisol stays high. Chronic burnout is often the opposite: after the axis is pushed too long, the same stressor produces less cortisol than it should, and the daily curve flattens. This is hypocortisolism.
It is not gland exhaustion — the regulatory parameters along the chain have been reset.
3 · Five candidate sites
Researchers propose five sites where the chain could be reset, from pituitary receptors and negative feedback to target tissues, and none is gland failure.Researchers propose five explanations, none of which is gland failure:
① Chronic CRH → pituitary receptor downregulation (doorbell always ringing, volume turned down) ② Negative feedback hypersensitivity → a little cortisol shuts the whole chain off ③ Adrenal response to ACTH weakens ④ Synthesis rate drops at some level (reversible, not organ damage) ⑤ Target tissues become more cortisol-sensitive → the system lowers output accordingly
4 · The flattened curve fails at both ends
Blunting shrinks the amplitude of the cortisol curve: too low a morning peak to get going, and no drop at night, so you are exhausted but cannot sleep.Cortisol is a waveform, not a water level. Healthy rhythm: morning surge (CAR) boots you up, gradual decline through the day, nighttime trough allows repair.
Blunting destroys the amplitude: morning peak too low → can't get going; nighttime doesn't drop → exhausted but can't sleep. This is not a paradox — it is two ends of the same flattened curve. A single blood draw captures one point and tells you little.