Cortisol and the 24 hour timeline.

Cortisol

Cortisol levels follow a predictable 24-hour diurnal cycle, peaking shortly after waking to provide energy and dropping to their lowest point around midnight to allow for sleep.

The 24-Hour Cortisol Timeline

• 2:00 AM – 3:00 AM: Levels begin to slowly rise from their nightly low as your body prepares to wake up.

• 6:00 AM – 8:00 AM (The Morning Peak): Cortisol surges sharply, peaking about 30 to 45 minutes after you wake up. This jump is called the Cortisol Awakening Response (CAR), which acts as your body's natural alarm system to clear brain fog and boost alertness.

• 8:00 AM – 12:00 PM (Morning): Levels remain relatively high and stable, supporting focus and high energy during the early part of the day.

• 12:00 PM – 6:00 PM (Afternoon): Levels steadily and gradually decline as your body transitions out of high-alert mode.

• 6:00 PM – 10:00 PM (Evening): Cortisol continues to taper down, reaching low levels that permit your brain to release melatonin for sleep.

• 10:00 PM – Midnight (Nighttime Nadir): Cortisol hits its lowest point (nadir) during the early part of the night, allowing for cellular repair and deep rest.