Definition
Cortisol is a hormone released from the adrenal cortex in response to stress signaling from the brain. Where adrenaline drives the immediate stress response, cortisol shapes the slower, sustained physiological response that follows.
What it can feel like
In short bursts, cortisol isn't perceived directly. In sustained release, the effects include disturbed sleep, early-morning awakening, increased appetite for high-energy foods, and a sense of restless fatigue. Many people describe feeling tired and wired at the same time.
Why it happens
Cortisol follows a daily rhythm and rises in response to stress. It mobilizes glucose, modulates inflammation, and supports sustained activity. When stress is chronic, cortisol release becomes dysregulated, which contributes to many of the physical features of long-term anxiety and depression.
When to see a clinician
Persistently elevated stress symptoms with early morning waking, weight changes, blood pressure changes, or unusual fatigue can warrant a medical evaluation that includes basic endocrine testing. Cortisol-related medical conditions (Cushing's syndrome, adrenal insufficiency) are uncommon but treatable when identified.