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.
In people who rarely exercise, heart rate and systolic blood pressure shoot up almost immediately with even a small increase in activity. This is mostly because the heart is not accustomed to pumping large amounts of blood, so it can supply more blood to the muscles only by pumping at a faster heart rate. Yet even though their heart rates tend to speed up quickly with light exercise, their peak heart rates tend to be lower when exercising hard than in folks who exercise regularly. Such blunted peak heart rates (also called chronotropic incompetence) tend to be associated with feeling less energy and vigor, since the heart can't provide as much blood as the body needs.