Knowing your own systolic and diastolic blood pressure readings is vital to your health and could save your life. And now there is overwhelming scientific evidence that using a home blood pressure monitor is superior to blood pressure readings made in the office of your doctor. But just like in the doctor’s office, you must have good blood pressure measuring techniques at home and strictly follow some specified procedures in order for your blood pressure readings to be accurate. According to the American Heart Association, it’s not uncommon to get incorrect home readings, not because the devices themselves are inaccurate, but because the individual using the device is not following good blood pressure measuring procedure. For example, you measure too frequently, use the wrong cuff size, or don’t sit quietly for a few minutes first. Or you take only single measurements or cherry-pick the highest blood pressure readings. All these mistakes can lead to incorrect estimation of your blood pressure at home.
Occasional high blood pressure readings are inevitable
Another reason for incorrect measurement of blood pressure readings at home is anxiety. Just like in the doctor’s office, anxiety can induce an elevation of blood pressure at home. Occasionally, people become obsessed about their need for taking good blood pressure readings as a measure of their health. This not only can cause overestimation of blood pressure, it can end up making hypertension worse overall. The inherent variability of blood pressure means that there will inevitably be some high readings. If you’re anxious, these high readings can exacerbate your anxiety, leading to further increases of blood pressure and setting up a vicious cycle. If this sounds familiar, frequent checking of your blood pressure is discouraged, and in extreme cases it should be discontinued altogether.
The 13 Cardinal Rules for Getting Accurate Blood Pressure Readings at Home
- Do not drink coffee, smoke, or exercise, within 30 minutes before measuring.
- Use an automatic, not manual device. Most devices specifically designed for use by patients in the home are fully automatic, so that the patient only needs to wrap the cuff around the upper arm and press a button for the machine to take the blood pressure readings and display the values for systolic and diastolic pressure on a screen.
- Use an arm cuff rather than a finger or wrist cuff. The arm devices are the most reliable and have the additional advantage that they measure pressure in the same artery that has been used in all the large studies of high BP and its consequences.
- Use a large cuff if your arm is large.
- Use one arm, not both.
- Support your arm on a flat surface so that the upper arm is supported at the level of the heart.
- Your back should be supported, and both feet should be flat on the floor.
- After you put the cuff on, sit for a few minutes before checking blood pressure.
- Take 3 readings rather than just one, 1-2 minutes apart, writing each one down using our Blood Pressure Chart for Monitoring Blood Pressure at Home (see below).
- Don’t take more than three readings.
- Check no more than twice a week except in these cases:
- your hypertension is severe
- you’re changing medications
- you’re getting an initial, reliable estimate of your “true” blood pressure (see below)
- Don’t check only when you think your blood pressure readings will be good or only when you think they will be high; check at random, ordinary times.
- Check you monitor’s accuracy at least once a year at the doctor’s office by comparing it to the office’s manual cuff.
How to get an initial, reliable estimate of your true blood pressure
Your “true blood pressure” is thought to represent your usual blood pressures over long periods of time. Even normal, good blood pressure readings will fluctuate continuously in a 24-hour period, and the variability is influenced by many physiological factors. Keep in mind that even good blood pressure can change by ≥20 mm Hg between readings. You should not be concerned about this.
The American Heart Association, the American Society of Hypertension, the European Society of Hypertension, and other groups all admit the difficulty of determining people’s true level on the basis of one or two measurements at the time of an office visit. These respected organization all recommend home blood pressure monitoring in order to get an initial, reliable estimate of your true blood pressure. Therefore, getting your true blood pressure readings at home is the very best way for you and your doctor to have the necessary information to make the best treatment decisions.
Here’s how to get an initial estimate of your true blood pressure at home, based on recommendations from all three professional organizations:
- Take three morning and three evening readings every day for one week. The morning readings should be taken first thing in the morning before taking any medication, and the evening readings should be taken before bed. After each reading, record the numbers in the chart below as shown in the example. You can download a pdf copy of this chart here.
- Discard the readings of the first day.
- Then calculate the average systolic (upper) and average diastolic (lower) values for all your blood pressure readings for the remaining six days. If you took three readings each morning and another 3 each evening, you should have a total of 36 readings on which to make decisions about diagnosis and treatment.
Blood Pressure Chart for Monitoring Blood Pressure at Home
How to interpret your “true blood pressure readings”
Our blood pressure chart reflects the standard classification system adopted by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (http://www.nhlbi.nih.gov/guidelines/hypertension/) and by the American Heart Association. However, it is now widely acknowledged that average daytime home blood pressure readings are lower than that taken in a doctor’s office. As a result, some authorities have recommended that 135/85 mmHg rather than 140/90 mmHg be used as the cut-off for hypertension.[1,2]You and your doctor should decide which values to use. If you choose the more conservative approach, you should be aware that an average systolic value greater than 135 mmHg or an average diastolic value greater than 85 mmHg represents a high probability that you have true hypertension, and you should consider a plan of action to improve those numbers over a period of time.. On the other hand, if the average is less than 125/76 mmHg, the probability of having true hypertension is quite low. If you fall somewhere between 125-135 mmHg systolic and 76-85 mmHg diastolic, you are in the grey zone in terms of whether you have true hypertension. Starting to follow basic lifestyle recommendations and natural therapies described in our Blood Pressure articles will still be beneficial for you if you fall into this grey zone.
If you do have true hypertension based on this self-measured average blood pressure readings at home approach be encouraged that there very effective and safe natural healing approaches to getting good blood pressure levels back in balance, and these involve addressing the underlying causes. Using natural treatments based on lifestyle changes and natural substances like vitamins and minerals allows your blood pressure readings to come down without negative side effects. Our Blood Pressure articles will give you a snapshot of key natural treatments for achieving a good blood pressure level.
This article was originally published in 2013 and has been updated.