Do you suffer from hypertension?
Are you on blood pressure meds?

Most of the people, including both, those with normal and those with high blood pressure, have their pick of blood pressure in the early morning hours, upon waking and beginning the day. This morning rise in blood pressure is not caused by the act of getting out of bed and beginning activity. It is a genetically preset system that automatically increases a person's pressure at that time.
Acctually, is due to the circadian rhythm (daily periodicity of one's body functions).