Why is my mother's blood pressure high in the mornings?

My mom has high blood pressure, particularly in the mornings. Is there any reason for this?

It is now well known that BP fluctuates throughout the day - could be she is bit more tense in am

Most strokes occur in the early morning, her meds need to be adjusted at night.

Because that’s when the stress hormones from the adrenals are increasing

This responds to the circadian rhythm, but an adequate handling and compliance should maintain the blood pressure in normal level throughout the day.