Ask the doctor: Are my blood pressure and heart rate changing normally during exercise?

Q. Sometimes I take a walk while wearing my blood pressure cuff. For the first few minutes, as I walk at a modest pace, my systolic blood pressure rises from 115 to 130 or so, while my heart rate hardly changes from its usual 60-something beats per minute. But when I start walking faster, my systolic pressure stays steady or sometimes goes down a bit, while my heart rate increases to 110. Is this a normal pattern? Can you explain what is going on?

A. When the average healthy person is sitting or walking at a normal pace, the heart, lungs, and blood vessels easily supply the body with all the oxygenated blood it needs. Start walking faster, or running, and the extra oxygen demanded by the leg muscles causes predictable changes in the circulatory system: the heart pumps faster and harder as it works to supply more blood to the active muscle; changes in the muscle tone of blood vessels redirect blood away from the digestive system and toward working muscle. These changes in heart rate, pumping intensity, and vascular tone usually cause a modest increase in systolic blood pressure. This is the pressure recorded as the heart contracts during systole (SIS-tuh-lee). It is represented by the upper number of a blood pressure reading.