Cortisol is your body's primary stress hormone. Released by the adrenal glands in response to physical or psychological stress, it evolved to help us survive short-term threats. The problem? Modern life keeps the tap running — and chronically elevated cortisol has wide-reaching health consequences.
What Cortisol Actually Does
In the short term, cortisol is your friend. It raises blood sugar for quick energy, suppresses non-essential functions (digestion, reproduction), and sharpens focus. This is the fight-or-flight response working exactly as designed.
But when cortisol stays elevated — due to work stress, poor sleep, overtraining, or chronic illness — those same mechanisms become destructive.
Effects of Chronically High Cortisol
- Weight gain, especially around the abdomen
- Disrupted sleep — difficulty falling or staying asleep
- Immune suppression — increased susceptibility to illness
- Blood sugar dysregulation — increased risk of insulin resistance
- Mood disturbances — anxiety, irritability, depression
- Muscle breakdown (catabolism)
- Reduced libido and reproductive function
How Is Cortisol Tested?
Cortisol follows a diurnal rhythm — it's highest in the morning (helping you wake up) and lowest at night. A single blood test captures a snapshot at one time point. Morning cortisol is the standard clinical measurement. Salivary cortisol testing across multiple time points gives a more complete picture of the daily curve.
