Yes, it is quite normal for people’s blood pressure to change throughout the day & night, or in different settings where you may measure your blood pressure. Many things, such as stress levels, food or drink intake, activity levels, even time of day can all affect a person’s blood pressure reading at any given time. In fact, there are published studies that show a given person’s blood pressure can change by up to 20mm within a day, based on activity levels, food/drink intake, stress, etc. This is why it is important to take your blood pressure on a regular basis, & review the overall trend of your blood pressure readings with your doctor.
One should not be too concerned about one single measurement. It is important to take measurements every day at the same time & to know one’s own BP trend, as BP continually changes throughout the day due to the daily fluctuation cycle & many other factors.