Before we look at how to use a home blood pressure digital monitor, and which ones are the best, let’s first consider what the blood pressure readings will mean. These figures are taken from the National Heart, Lung and Blood Institute.

Digital Home Blood Pressure Monitors v Doctor’s sphygmomanometer

When you get your blood pressure measured at the doctor’s office, he/she will place a cuff around your upper arm, level with your heart.

The cuff is inflated, and then, while the doctor listens on his/her stethoscope placed on your arm just below the cuff, the cuff is slowly deflated. the doctor is listening out for the first signs of a "tapping sound" which signals the point when the cuffs pressure is just less than the pressure of your blood, and blood flows intermittently past the cuff during heart beat. At this point, the doctor notes the pressure on the sphygmomanometer. This is your systolic blood pressure.

The cuff continues to be deflated until the "tapping" sound completely disappears. This is the point where full blood flow has been restored, and represents your diastolic blood pressure.

Measurements taken by your doctor are the most accurate, and most reliable. However, due to a phenomenon called "White Coat Syndrome", some patients find their blood pressure raised by the mere act of visiting the doctor. I suffer from this, and find that my blood pressure is significantly lower (even normal) at home, yet at the doctor’s office, it is always high. Because of White Coat Syndrome, more and more doctors are recommending digital home blood pressure monitors for their patients.

If decide to buy a home monitor, you MUST get it checked at your doctor’s office for accuracy. These meters can be extremely accurate, but you need to check that yours is calibrated properly. All you need to do is to go and get the doctor to check your blood pressure, wait 2 minutes, and then take your blood pressure using your digital meter. The two readings should be very similar (they wont be 100% the same as blood pressure varies). Once accuracy is confirmed, you can confidently take your blood pressure at home.

Types of personal blood pressure monitors

I have seen and used two types of home monitors. One has a cuff that goes around your wrist, while the other has a cuff that goes around your upper arm (at the level of your heart). While I have not done extensive testing, I did find the wrist cuff more temperamental and inaccurate. My own recommendation is that you buy a blood pressure monitor with the arm cuff. They are both similarly priced and can be bought for between $50 – $100.

Precautions when taking your own blood pressure

It is important that your are completely relaxed when you measure your blood pressure. There are also a few other guidelines that you should stick to before taking your reading:

1. Empty your bladder before sitting down to take a reading.
2. Don’t drink coffee for at least an hour before measuring your blood pressure.
3. Don’t smoke for at least 1 hour before.
4. Sit for five minutes with your back supported and your feet flat on the ground before taking your blood pressure. Keep your arm supported on a table at heart height.
5. Do not wear tight fitting clothes on your arm. When you fit the cuff, your rolled up sleeve should not be constricting your arm at all. If in doubt, take off your top.
6. Take two readings two minutes apart, and find the average.

Where to Buy Blood Pressure monitors

With these personal monitors being relatively cheap and yet highly accurate, we recommend you buy one to use at home. This will prevent "White Coat Syndrome" where your blood pressure is elevated just because you visit the doctors. However, when you get your, you must visit your doctor to check its accuracy. 

Our recommended supplier of blood pressure monitors usually have a range of wrist and upper arm cuff monitor.  See our guidelines to choosing a blood pressure monitor, and see what is available online:

Choosing a blood pressure monitor

In animals at least, the researchers were able to prevent preeclampsia in pregnant mice leading to excitement that a treatment may be possible for humans.

Source: University of Texas

1. The best option for most people is a digital home blood pressure monitor.  While they are not as accurate as the mercury devices you see at your doctors, they don’t require the use of a stethoscope, and also don’t require any specific training.
2. Digital blood pressure monitors come in three types – arm, wrist & finger.  The most accurate of these is the upper arm cuff model, and it is difficult to recommend any other type UNLESS there is some medical reason why you cannot use an upper arm monitor.
3. Read the instructions for using your monitor – a cuff that is not fitted properly will give inaccurate readings.
4. Look for additional features that you will find useful, e.g. battery operated for portability, reading display size for those with vision problems, memory (so that previous readings are always available to check), and warranty.

A good home blood pressure monitor can alert you to problems.  If you find you do have high blood pressure, do consult your doctor. Below are a list of home blood pressure monitors available online:

Obviously, with the delicate nature of blood vessels, high blood pressure can be a big problem during pregnancy, as it can affect the developing foetus.

In the articles below, we explore issues like pre-eclampsia and HELLP syndrome.

My idea for these experiments was to look at various factors that have been reported as affecting blood pressure.  For those of us with hypertension (high blood pressure), this type of information if very important.

When I started these experiments, my own blood pressure was around 140/100.  Through carefully watching my diet, and increasing the level of exercise, my blood pressure dropped to normal levels.  In fact, its not unusual for my blood pressure to be now be around 100/60.

For all of these experiments, I used a home blood pressure monitor, with the upper arm cuff.  I did test the accuracy of this when I first started using it by comparing the readings with those taken by my doctor.

In this experiment, I wanted to see how exercise affected my blood pressure.

The experiment was simple.

I would do 7 minutes of weight training while seated (this involved shoulder presses).  Immediately afterwards I took my blood pressure twice, with three minutes in between.  I then did another 7 minutes of weights, but this time standing up (bicep curls).  After this 7 minutes I took my blood pressure immediately, and for several minutes afterwards.

Here are my results:

Here are my results in Graphical format:

Note that the arrows in the graph represent 7 minutes of exercise.

The immediate thing to notice is the obvious.  After exercise, my heart rate increases.  Heart rate increases to increase the flow of blood around the body so that increased oxygen uptake and increased release of carbon dioxide from the tissues can take place.

As for blood pressure, there are slight increases in both diastolic (lower) and systolic pressure (upper) pressures.  From rest, until the first measurement after the first 7 minutes of exercise, the systolic increase by 11 mmHg.  That represents a 9.8% increase in systolic pressure over the resting pressure.  The same measurement for diastolic shows the pressure going up 13 mmHg, representing an increase of 19.7% increase over the resting diastolic pressure.  It would therefore seem that in my case, both diastolic and systolic increase after exercise, though diastolic increase more.  Remember that the diastolic pressure is the pressure in my blood vessels BETWEEN heart beats, so my system is under higher pressure when at “rest”, after exercise.

12 minutes after exercise finished both blood pressure and heart rate was still elevated, so it appears that in my case at least, exercise did increase blood pressure, and that the increase lasted for some time after exercise finished, as did my elevated heart rate.

It is very difficult to define exactly what constitutes low blood pressure, since everyone is different. One person may suffer symptoms at 90/60 while another is totally fine at blood pressures which theoretically should have them on their back.

If you have no symptoms there is no reason for concern. Only when blood pressure drops below the level required by your body and cells, is there a real problem. When this happens, you get symptoms.

Symptoms of low blood pressure

• Dizziness
• Lightheadedness
• Fainting

Under severe low pressure, symptoms can include chest pains. Also, without the necessary pressure in the blood, the kidneys cannot filter out the toxins in your blood, and there will be an increase in blood levels of urea and creatine.

Causes of Low Blood Pressure

Low blood pressure can have a variety of causes including:

• Medication, including high blood pressure medicine, and medication for coronary heart disease.
• Anti-anxiety, and anti-depressant drugs.
• Diuretics
• Alcohol
• Dehydration – common when someone has diarrhea and-or vomiting. It is important to drink plenty of fluids (plain water works best) if you are ill with these.
• Slow heart beat
• Inflammation of organs in the body, e.g. acute pancreatitis
• Heart disease – when the walls of the heart become weakened and can no longer pump with the required force.

Should you consult a doctor?

Yes if:

• You lose consciousness when you stand up
• You constantly feel weak, light headed or tired.

Facts on low blood pressure

In younger people, low blood pressure can be a sign of chronic fatigue syndrome.

In older people, low blood pressure can indicate heart disease.

Young women (below 40) may find their blood pressure drops below 90/60 during:

• pregnancy
• hot weather
• dieting

Treatment for Low Blood Pressure

Since any treatment will depend on the cause of your low blood pressure, you must consult your doctor. It may be that some component of your lifestyle has caused the low blood pressure, and simple changes to that can restore your blood pressure to normal.

I used a filter coffee machine to prepare a large cup of coffee, made with decaffeinated ground coffee. The process was exactly the same as my experiment to see if caffeine coffee affected bloood pressure, except for the type of coffee, which in that case was obviously a standard caffeine coffee. In the current experiment, the coffee was decaf.

Here are my results:

Here is the data as a graph showing the effect of de-caffeine coffee on blood pressure:

Before drinking the coffee, my blood pressure was fairly stable at around 125/82. However, at 10:31, around 5 minutes after drinking the decaf coffee, my blood pressure fell to 116/78, and fell even further at 10:36 to 112/75.

For 10:31 to 10:50, my blood pressure was below the starting blood pressure of around 125/82. From 10:58 until the end of my experiment, blood pressure had returned to near the starting level.

It appears from these results that drinking the decaffeinated coffee reduced my blood pressure for a period of around 25 minutes before blood pressure returned to normal.

Now, whether this is due to the decaf coffee itself, or some other factor involved remains to be seen. For example, it may well be that the decaf coffee itself has no effect on blood pressure, and something like the heat in the drink was responsible.

As a follow up experiment, I need to drink an equivalent volume of hot water.

That will be my next experiment.

To prepare for each set of readings, I sat down for 5 minutes before taking the first reading.

The coffee used in this experiment was strong filtered coffee. After taking a few baseline readings, I drank the coffee in one go. The amount was equivalent to 4 small expresso coffees. I then continued to take my blood pressure every few minutes. I then sat as still as possible, taking my blood pressure every three minutes.

Here are my results:

Here is the data as a graph showing the effect of caffeine coffee on blood pressure:

You’ll see that there is an almost immediate increase in systolic pressure, followed by a drop. This then increases again about 10 minutes after drinking the coffee to a maximum measured blood pressure of 138/89 about 23 minutes after the coffee was drunk. The blood pressure then starts dropping again, until normal blood pressure is restored at around 30 minutes after drinking the coffee.

What we see happening is a temporary increase in blood pressure in response to the coffee, which the body then corrects. How caffeine raises blood pressure seems to be unclear, but what is certain in my case is that it did raise my blood pressure, but only for a short period of time.

For those with high blood pressure, it would appear that coffee could be a problem due to the high spike after drinking the coffee. However, since my blood pressure is normal, I wont be switching to decaf.

My next experiment is to see what effect drinking filtered decaffeinated coffee has. Is it the caffeine in the coffee that raised my blood pressure, or something else?  You can see the results of my experiment on the does decaffeinated coffee affect blood pressure page.  The results may surprise you!

To prepare for each set of readings, I got into position, and waited quietly for 5 minutes before taking the first reading.

I then took a minimum of 3 readings for each position, with 3 minutes between each reading. The results I show you below are the average of the readings for each position. I have also included heart rate for the three positions.

Blood pressure when lying down:

Blood Pressure Average: 115/70
Heart Rate: 66

Blood pressure when sitting down:

Blood Pressure Average: 120/79
Heart Rate: 72

Blood pressure when standing :

Blood Pressure Average: 121/78
Heart Rate: 75

As you can see, my blood pressure (and heart rate) was lowest when lying down. This is as expected, since the body is not having to work too hard to pump blood around the body, which is all pretty much in the same horizontal plane.

When the body then sits up, there is an increase in blood pressure and heart rate. Again, this is as I would have expected, since the body is now having to work a little harder to get the blood around the body.

Finally, when standing, there was no noticeable difference in my blood pressure from the sitting position. I had expected to possibly see a slight drop in blood pressure, though no change is not a big surprise. When you stand up, gravity causes blood to naturally wants to pool in your leg veins causing a drop in blood pressure. However, the autonomic nervous system tries to correct this by narrowing your blood vessels (which increases blood pressure) and increasing your heart rate. We did see the increased heart rate. The reason for no apparent drop in blood pressure is probably because the first reading was taken 5 minutes after standing. This would have given the body time to adjust.