Measurement of cortisol levels is usually done by blood or urine. Cortisol is secreted by the adrenal cortex, and its secretion is rhythmic, so blood and urine cortisol levels should be measured at 8 a.m., 4 p.m., and 12 p.m. respectively. Normal adult blood cortisol levels range from 165 to 441 nmol/L at 8 a.m., 55 to 248 nmol/L at 4 p.m., and 55 to 138 nmol/L at 12 p.m. Outside of these ranges, cortisol is considered high. Normal adult urinary free cortisol excretion is 130~304nmol/24h, beyond this range is high cortisol. High cortisol may appear in late night, irregular work and rest, pituitary disease, adrenocortical adenoma and so on. High cortisol should go to a regular hospital in time and be given standardized treatment under the guidance of a doctor.