Which effect is associated with high night-time cortisol levels?

High nighttime cortisol levels are indicative of an underlying issue with the body's stress response systems. Normally, cortisol levels are expected to decline in the evening and be at their lowest during the night, facilitating restful sleep and allowing for effective recovery. When cortisol levels are elevated during this time, it often reflects a dysregulation that can stem from chronic stress or hidden stressors affecting the individual.

When cortisol remains high at night, it can disturb the natural circadian rhythm, leading to difficulties in achieving restorative sleep and preventing the body from engaging in necessary healing processes. This disruption is not only a symptom of stress but can also perpetuate a cycle where the body remains in a heightened state of alertness, reducing overall well-being.

Other options, such as improved sleep quality and increased melatonin production, contradict the changes seen with high cortisol levels. Elevated cortisol at night is usually associated with poor sleep quality, not improvement, and can suppress melatonin production, which is essential for initiating and maintaining sleep. Additionally, lowered stress responses would not be expected from high cortisol levels; rather, they indicate an active stress response that can negatively impact health. Hence, the correct answer highlights how elevated nighttime cortisol serves as a signal for identifying underlying hidden stressors that need to be addressed