Cortisol

You wake up at 3:17 am, mind already on alert, heart slightly racing, unable to fall back asleep until 5. It is not random, it is not stress "in your head" either: most likely it is a premature rise of cortisol, several hours ahead of the time set by your internal clock.

Cortisol is the hormone the adrenal glands release on a strict circadian rhythm: a peak around 7-8 am to launch the day, then a steady decline to a nighttime trough near midnight. It is this bell-shaped profile, high in the morning and low at night, not the isolated value of a single blood test, that defines a balanced cortisol.

The cortisol that wakes you too early

When the HPA axis (hypothalamus-pituitary-adrenal) stays activated in the background, cortisol starts climbing back up at 2 or 3 am instead of 5. By then melatonin has collapsed, blood sugar is low, and the smallest thought triggers full awakening. Recent meta-analyses confirm in chronic insomnia an HPA over-activity during the second half of the night, with higher nocturnal cortisol and a blunted morning reactivity. The reserve wears out at night, and morning finds a cell already tired.

Repair the rhythm before the level

Measuring cortisol once is almost useless: you need to read its circadian profile (saliva or urine, four samples). The levers that bring the bell back in shape: natural light within the hour after waking, a light carb-containing dinner rather than skipped, digestive window closed three hours before bedtime, no coffee after 2 pm. Phosphatidylserine and ashwagandha have, in small trials, shown a lowering effect on nocturnal cortisol. Some people report improvement after 6 to 8 weeks, always under supervision especially if thyroid or blood pressure treatment is ongoing.

Related terms

• HPA axis
• Melatonin
• Nocturnal hyperarousal
• Phosphatidylserine
• Ashwagandha