The CDC estimates that about 1 in 3 U.S. adults — or about 70 million people — have high blood pressure (HBP), also known as hypertension. Only about half of these people have their hypertension under control. This common condition increases the risk for heart disease and stroke, two of the leading causes of death for Americans.
Because there are no symptoms for hypertension and no way to see fluctuations in blood pressure, measuring is the only way to know if you are at risk. Because one measurement taken at the doctor’s office provides a snapshot of your blood pressure at that moment, a record of readings taken over time provides a clearer picture of the situation inside of your arteries.
Some people experience anxiety when at a doctor’s office, causing their blood pressure reading to be higher than normal. This condition is known as “white-coat hypertension.” Data suggests that 15 to 30 percent of those believed to have HBP may have lower blood pressure outside of the doctor’s office setting.
“Blood pressure is affected by various short-term factors, such as emotions, stress, pain, physical activity and drugs — including caffeine and nicotine,” says Dr. Nassir Azimi, a board-certified cardiovascular disease and interventional cardiology specialist affiliated with Sharp Grossmont Hospital. “Multiple measurements over time can better predict hypertension than the single measurement taken during a visit to your doctor’s office.”
Understanding the numbers
The two numbers in a blood pressure reading describe the amount of force pushing against the artery walls when the heart is contracting and when it is at rest. According to the American Heart Association, the optimal blood pressure reading is one in which the systolic, or top number, is less than 120 and the diastolic, or bottom number, is less than 80.
If your blood pressure reading is higher than normal during your office visit, your doctor may recommend that you monitor your blood pressure at home. Analyzing a record of blood pressure readings taken over time can help determine whether the reading during your doctor’s visit is from “white-coat hypertension” or is indicative of chronic HBP.
While home blood pressure monitoring is generally encouraged, it is important to note that home monitoring devices are not recommended for certain patients. For people with an irregular heartbeat, a home-monitoring device may not be the best way to get accurate measurements. It is also important to calibrate your digital device periodically by bringing it to the doctor’s office for simultaneous comparison with the doctor’s manual sphygmomanometer, an instrument used to measure blood pressure.
“For some patients, home blood pressure measurements may be helpful when combined with regular monitoring at your doctor’s office,” says Dr. Azimi. “Ask your doctor about whether taking blood pressure measurements at home is right for you.”