You can’t depend completely on blood pressure measurements done only in a doctor’s office because being active, having “white coat syndrome,” (feeling nervous or stressed), or an improper hurried measurement can raise blood pressure considerably. In one study, systolic blood pressure was 7.3 mm Hg higher in a doctor’s office than when measured more precisely in a research setting (JAMA Intern Med, 2020 Dec 1;180(12):1655-1663).
Factors That Can Raise Your Blood Pressure Readings
A study of 2,300,000 blood pressure measurements taken by Kaiser Permanente Southern California showed the wide variety of factors that can falsely raise blood pressure (Permanente Journal, 2009;13(3):51-54), including:
• blood pressure cuff too small
• blood pressure cuff not snug at the start
• blood pressure cuff placed over clothing
• not resting 3-5 minutes before taking the reading
• exercising or eating beforehand
• not supporting arms, legs, feet or back, which can cause muscles to contract and raise blood pressure
• crossing the legs
• holding arms above or below heart level
• feeling excited
• thinking about an emotional situation
• having taken in alcohol or caffeine
• having a full bladder
• having taken certain medicines such as cold remedies or allergy pills
• having eaten certain foods such as those that contain tyramine (fermented, pickled, brined or cured foods)
• room temperature too hot or too cold
How To Take Your Own Blood Pressure Properly
I recommend that everyone should have their own upper-arm blood pressure cuff (wrist cuffs are not very dependable). They are inexpensive and are available at any drug store or online. When and how you check your blood pressure can affect your results.
• Take your blood pressure after lying on your bed for at least five minutes, either before you go to sleep at night or early in the morning before you start moving around.
• Don’t smoke, drink caffeinated beverages or exercise for at least 30 minutes before taking your blood pressure.
• Don’t talk while taking your blood pressure.
• Make sure your bladder is comfortably empty.
• Prop yourself into sitting position on your bed, or sit on a chair with your arm on a table.
• Sit with your back straight and well-supported; do not cross your legs.
• Keep your upper arm where you will place the cuff at heart level.
• Place your elbow on the table or bed with your palm facing up.
• Make sure the cuff fits snugly with no looseness on the upper arm.
• Take two or three readings at least one minute apart. Do this for a week, and average the readings. If the average is over 120/80, your blood pressure is too high.
Lifestyle Changes to Lower High Blood Pressure
Almost 50 percent of North Americans have high blood pressure, which increases risk for heart disease, strokes and kidney disease. Many people don’t know that they have high blood pressure because they may have no symptoms. High blood pressure is defined as anything greater than 130/80 by almost all medical groups, including the American Heart Association and the American College of Cardiology. The numbers used to be 140/90, but that misses a lot of people who could have been saved from a preventable premature death just by making some lifestyle changes (Annals of Internal Medicine, March 6, 2018). A study called the SPRINT TRIAL showed that bringing blood pressure below 120 significantly reduces heart attack and stroke risk (N Engl J Med, 2015; 373:2103-2116). Having a systolic blood pressure over 130 doubles your chances of suffering a heart attack, stroke, or heart or kidney failure, and puts you at increased risk for developing dementia in later life. Known causes of high blood pressure include diabetes, pregnancy, dehydration, cardiovascular disease, obstructive sleep apnea, kidney disease, thyroid problems, nervous system problems, and so forth.
Most patients with a systolic blood pressure between 130–139 mm or diastolic blood pressure between 80–90 mm can reduce their blood pressure to 120/80 or lower without taking medication, by losing weight, eating healthful foods, cutting down on salt, increasing potassium-rich foods, exercising regularly and not smoking or drinking.
Since you can get a false high or low blood pressure reading in a doctor’s office, I think everyone should have their own blood pressure cuff. There are so many things that can raise your blood pressure that the best time to check your blood pressure is after lying in bed for at least five minutes. Follow the instructions above.
If your average systolic blood pressure is over 120 or your average diastolic pressure is over 80, you should immediately make all the lifestyle changes necessary to lower it. Your doctor may feel that you need medications to lower high blood pressure, but lifestyle modifications can often bring your blood pressure to normal so it may not be necessary for you to stay on medication.
Lifestyle changes to lower blood pressure include:
• lose weight if overweight
• eat lots of vegetables, fruits, nuts and beans
• avoid sugared drinks (including fruit juices) and sugar-added foods, red meat, processed meats and fried foods
• get plenty of exercise
• keep your blood levels of hydroxy-vitamin D above 20 ng/mL
Your doctor may prescribe medication until your lifestyle changes bring your blood pressure back to normal. See my report on Blood Pressure Guidelines