How to read the numbers: Target = the value we aim for · Risk = what to watch out for · Fact = a finding from research or biology
Cortisol peak
Cortisol naturally rises shortly after waking and gives you energy for the start of the day, then gradually falls. You can support this rhythm with a consistent wake-up time and daylight early in the morning.
Under chronic stress
Chronic stress can keep cortisol elevated or, conversely, flatten its daily curve; the size of the change varies greatly between people. If you suspect a problem, it can be measured with a doctor from saliva at several times of day.
To reset your cortisol rhythm
Three weeks is a rough guide – with a consistent sleep and light routine, the daily rhythm often improves noticeably within a few weeks, though research does not set an exact cut-off. Go to bed and get up at the same time, weekends included.
Cortisol is released by the adrenal glands in response to stress — both physical and psychological. It is a glucocorticoid: it raises blood glucose, suppresses immunity, constricts blood vessels and heightens alertness. In an acute situation, it is a lifesaver. The problem begins when the "acute situation" becomes permanent.
Cortisol and testosterone compete for the same precursor (pregnenolone). Chronically high cortisol literally "steals" the raw material your body needs to make sex hormones. This is known as the "pregnenolone steal".
What cortisol actually does
Cortisol mobilises energy reserves (glycogen → glucose), suppresses inflammation in the short term, regulates the sleep cycle and influences memory and emotions. Its natural rhythm: a peak at 6–8 am (on waking), a gradual decline over the day and a low point around midnight. This rhythm synchronises the entire hormonal system.
The cortisol rhythm — the key to energy
The morning cortisol surge (the Cortisol Awakening Response — CAR) is stronger if you get up at the same time every day, expose yourself to daylight within 30 minutes of waking and do not eat immediately after getting up. A disrupted CAR is the first sign of adrenal dysregulation.
Chronic stress = chronically high cortisol
The consequences: insulin resistance (cortisol raises blood sugar), visceral obesity (fat is stored around the belly), suppressed immunity (recurring infections), damage to the hippocampus (memory problems), hypothyroidism (impaired T4→T3 conversion) and reduced testosterone.
How to lower cortisol — the protocol
Adaptogens: Ashwagandha (KSM-66, 300–600 mg) lowers cortisol by 27% in randomised studies. Rhodiola rosea for psychological stress. Phosphatidylserine (400 mg) for post-workout cortisol. Sleep protocol: darkness before 10 pm, bedroom temperature of 18–19 °C. Morning light (10 minutes outdoors within 30 minutes of waking) anchors the CAR. Breathing techniques: 4-7-8 or coherent breathing at 5.5 breaths/min.
