Q: I am wondering what would be considered the normal range of blood pressure variation within a five minute span. My first reading is usually about 20 points higher than the second reading, which is done about 5 minutes later.
A: It is well known that blood pressure can vary within a five minute span. Because of this, it is recommended that you rest for five minutes prior to a reading being taken. This allows your blood pressure to stabilize before the reading is taken. See this article on the U.S. National Library of Medicine site. Averaging three readings taken 5 minutes apart to determine blood pressure has also been suggested as a more accurate way to determine blood pressure at any given moment in time.