Which statement best describes the typical cortisol pattern in a healthy individual?

• A. Cortisol is highest in the morning and lowest at night
• B. Cortisol peaks at midnight
• C. Cortisol is constant throughout the day
• D. Cortisol is higher in the evening

Answer: (A)

Cortisol follows a daily rhythm tied to the body’s circadian cycle. In healthy individuals, cortisol rises in the early morning to help wakefulness and energy, then gradually declines throughout the day to reach its lowest level late at night. This morning peak and nightly low best describe the normal pattern.

The other described patterns don’t fit this natural rhythm: there isn’t a peak at midnight, cortisol isn’t constant across the day, and it isn’t higher in the evening. Understanding this diurnal variation is important for interpreting cortisol tests, especially when timing of collection can affect results.