Sleep, cortisol, and the HPA axis: where 'stressed' becomes measurable

"Adrenal fatigue" isn't a real diagnosis. The HPA axis - hypothalamus, pituitary, adrenals - is real, measurable, and far more about sleep architecture than about cortisol-support powder. Here's what cortisol patterns actually look like, what to test, and the interventions that reset the axis without supplements.