Cortisol

Cortisol is a steroid hormone produced by the adrenal glands. It's essential for the stress response, regulating metabolism, reducing inflammation and controlling the sleep-wake cycle. Cortisol follows a diurnal rhythm — highest in the morning and lowest at night.

Chronic high cortisol leads to weight gain (especially abdominal), high blood pressure, sleep disruption, anxiety, depression, impaired immune function, brain fog, irregular periods and decreased libido. It can disrupt other hormones including thyroid and reproductive hormones.

Chronic stress (work, relationships, finances), sleep deprivation, over-exercising, excessive caffeine, poor diet, and certain medical conditions (Cushing's syndrome — rare). Modern lifestyles with constant stimulation keep the HPA axis chronically activated.

Prioritise sleep (7–9 hours), practice stress management (meditation, deep breathing, yoga), moderate exercise (avoid over-training), reduce caffeine (especially afternoon), eat balanced meals, maintain social connections, and consider adaptogenic herbs (ashwagandha, rhodiola).