What is cortisol?

Cortisol is produced by the adrenal glands on top of the kidneys and is often called the stress hormone. It raises blood sugar for quick energy, controls inflammation and helps regulate blood pressure and the sleep–wake cycle. Levels naturally peak about 30 to 45 minutes after waking, known as the cortisol awakening response, and fall at night. Short bursts are healthy, but long-term high cortisol is linked to weight gain, poor sleep, weakened immunity and high blood pressure. Cushing’s syndrome is caused by too much cortisol, and Addison’s disease by too little.