When you brake at a traffic light, your body releases cortisol. When you have a presentation — cortisol. When you argue with your partner — cortisol. This hormone is designed for short, intense use — and then it should drop. The problem with modern life is that cortisol never fully drops.
How to read the numbers: Target = the value we aim for · Risk = what to watch out for · Fact = a finding from research or biology
Healthy morning level
Cortisol is highest shortly after waking and falls during the day; the threshold shown is indicative, as reference values differ by laboratory and method. Schedule the test for the morning and compare the result with your laboratory’s own range.
Amygdala under chronic stress
Research, mainly in animals and brain-imaging studies in humans, suggests chronic stress alters the structure and activity of the amygdala, the fear centre; the 3× figure is a simplification. The good news is that regular exercise, sleep and breathing or meditation practice can calm it.
diseases are stress-related
Chronic stress keeps the body in a state of low-grade inflammation, so it contributes to the onset or worsening of many chronic diseases; the exact 60% share, however, is only a rough estimate. Build at least one regular activity into your day that reliably calms you.
What long-term cortisol does to your body
Chronically elevated cortisol suppresses immunity, raises blood pressure, damages the hippocampus (the memory centre), increases insulin resistance, suppresses testosterone and progesterone, accelerates biological ageing and shortens telomeres.
The HPA axis and adrenal exhaustion
The hypothalamic-pituitary-adrenal (HPA) axis is the control system for the stress response. Under chronic stress this axis becomes dysregulated — the cortisol rhythm flattens, the morning peak disappears and fatigue becomes chronic.
A normal cortisol rhythm: high in the morning (gives you energy), low in the evening (lets you sleep). If you feel tired in the morning and come alive in the evening — your cortisol rhythm is inverted. And it's measurable.
What it does to the brain
In low doses, cortisol improves memory. In chronically high doses, it damages the hippocampus — the brain region responsible for forming new memories and spatial orientation. Studies show that people under chronic stress have a measurably smaller hippocampus.
