- High blood pressure
- Keeping blood pressure stable
What is blood pressure variability?
Our blood pressure (BP) changes all the time. This happens naturally throughout the day due to the various activities and emotions we experience, and is not a cause for concern. However, some people who have high BP may have greater variability—very high sometimes and normal at other times—and may need to be cautious as they appear to have an increased risk of stroke, heart disease and death compared with people whose BP does not vary too much.
The variations in BP that cause concern are those where there are wide fluctuations from one BP reading to another BP reading.
Why does my blood pressure differ in clinic and at home?
If your blood pressure (BP) measurements are higher at home than at your doctor’s office, you have what is called masked hypertension. It may be due to a decrease in stress at your doctor’s office or an error in measuring your BP at home.
Masked hypertension occurs if a calm, quiet environment at your doctor’s office is less stressful than the environment at home.
Additionally, if you have consumed alcohol, caffeine or smoked at home before taking your BP reading, it may cause a spike in the reading as well.
On the other hand, if the opposite is true, you may be experiencing what is known as white-coat hypertension. This occurs because the stress or anxiety of being in your doctor’s office causes your BP to be higher than it normally is at home.
On average the difference between the reading at home and at the clinic is around 10 mmHg for the top (systolic BP) number and 5 mmHg for the bottom (diastolic BP) number. In some people this difference can be greater.
What should I do if my blood pressure reading is always different?
Firstly, make sure that everything is in order with your blood pressure (BP) monitor at home and that you are using the correct technique. If you are not sure of this, share your concerns with your doctor.
Sometimes, BP readings are different because measurements are taken in different arms. Generally, a small difference in BP readings between arms is not a health concern. However, if you notice a difference of more than 10 mmHg for either your systolic or diastolic BP, it may be a sign of underlying problems such as blocked arteries in your arms, kidney disease, diabetes or heart defects.
In any case, your doctor is likely to manage your BP based on the higher BP readings.
Measuring blood pressure accurately
There are many kinds of blood pressure (BP) monitors available. The sphygmomanometer is the device used by your doctor to take your BP reading. It includes an arm cuff, a squeeze bulb to inflate the cuff, a stethoscope, and a gauge to measure the BP or a unit to display the BP reading.
The cuff is inflated around the upper arm and the stethoscope placed on the skin over an artery. The inflating of the cuff temporarily stops flow of blood in the artery. This is when the BP measurement is taken, which is displayed on a circular dial with a needle. The reading on the gauge when blood flow is first heard is the systolic BP, whereas the reading when blood flow can no longer be heard is the diastolic BP.
When choosing a BP monitor for home use, there are several types you can choose from7,8:
How is blood pressure measured at home?
- Blood Pressure UK. Blood pressure news. Large blood pressure variations over months may increase stroke risk. Available at http://www.bloodpressureuk.org/mediacentre/Bloodpressurenewsarchive/Bloodpressurevariationsmatter. Accessed 8 October, 2019.
- WebMD. Big swings in blood pressure could spell trouble. Available at http://www.webmd.com/hypertension-high-blood-pressure/news/20150727/big-swings-in-blood-pressure--could-spell-trouble. Accessed 19 September, 2019.
- Mayo Clinic. High blood pressure (Hypertension). Available at http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/expert-answers/blood-pressure/faq-20057853. Accessed 19 September, 2019.
- Blood Pressure UK. White coat hypertension (and white coat effect). Available at http://www.bloodpressureuk.org/bloodpressureandyou/medicaltests/whitecoateffect. Accessed 19 September, 2019.
- Mayo Clinic. High blood pressure (Hypertension). Available at http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/expert-answers/blood-pressure/faq-20058230. Accessed 19 September, 2019.
- Encyclopedia.com. Sphygmomanometer. Available at http://www.encyclopedia.com/topic/Sphygmomanometer.aspx. Accessed 19 September, 2019.
- WebMD. Home blood pressure test. Available at http://www.webmd.com/hypertension-high-blood-pressure/home-blood-pressure-test. Accessed 19 September, 2019.
- MedlinePlus. Blood pressure monitors for home. Available at https://www.nlm.nih.gov/medlineplus/ency/article/007482.htm. Accessed 19 September, 2019.
- The Blood Pressure Association. Home blood pressure monitoring booklet. Available at http://www.bloodpressureuk.org/BloodPressureandyou/Homemonitoring. Accessed 8 October, 2019.